JPH0584470B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a short circuit detection and display device attached to a power distribution line.

(Prior art) Conventionally, when a ground fault occurs in a distribution line, the substation circuit breaker is opened first, and then the substation is shut off, from the viewpoint of early detection of the faulty section, isolation of the faulty section, and early transmission of power to the healthy section. At the same time, power is retransmitted to the healthy section by sequentially turning on the section switches on the power supply side, and when the section reaches the ground fault section, the substation circuit breaker is shut off again. When the circuit breaker of the substation is closed again, the section switch that separates the ground fault fault section is locked in the open state, only the ground fault fault section is isolated, and power is retransmitted only to the healthy section. , searching for ground fault sections. Once a ground fault fault section has been found, the ground fault point is detected by repeatedly measuring the insulation resistance of related power distribution equipment installed on each utility pole in the fault section. As mentioned above, in the past, after the ground fault fault section was identified, the resistance of the related power distribution equipment installed on the utility poles existing in the ground fault fault section was sequentially measured for each utility pole. There was a problem with the work that it took a long time, and there was a problem that it took a long time to detect the ground fault point.

In order to solve the above problems, for example, a patent application filed in 1983-
A short circuit/ground fault direction detection display device such as No. 281323 has been proposed.

In this short circuit/ground fault direction detection display device, a short circuit detection circuit is connected to the current transformers installed in the two sets of distribution lines so that short circuits can be detected. It is designed to output a short circuit current detection signal. Further, a no-voltage detection circuit is provided which detects the voltage state of the distribution line based on the current transformer and outputs a no-voltage detection signal when the circuit breaker at the substation branch is tripped due to the short circuit current.

When both the short circuit current detection signal and the no-voltage detection signal are input, the short circuit/ground fault direction detection display device displays a short circuit.

Furthermore, a similar current transformer is provided on the remaining one-phase distribution line to supply driving current for each of the circuits, and a power supply circuit is provided that is charged by the charging current output from the current transformer. ing.

As mentioned above, one current transformer is used for the power supply circuit, and unlike the other phases, a short circuit detection circuit is not connected to that current transformer because short circuit current flows into the distribution line of that one phase. This is to avoid adverse effects from the power supply circuit in case of

(Problems to be Solved by the Invention) Therefore, the short circuit detection and display device as described above has a problem in that it can only detect short circuits in two-phase distribution lines.

Structure of the Invention (Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems, and the short circuit detection display device of the present invention is designed to prevent short circuit current flowing through the power distribution lines by providing a short circuit current flowing through the power distribution lines. A short-circuit detection circuit detects the current through the current detector and outputs a short-circuit current detection signal, and detects the no-voltage state of the distribution line through the current detector when the substation circuit breaker trips. a no-voltage detection circuit that outputs a voltage detection signal; and a short-circuit detection gate circuit that outputs an operation signal when both the short-circuit current detection signal from the short-circuit detection circuit and the no-voltage detection signal from the no-voltage detection circuit are input. , a short-circuit indicator that operates to display a short-circuit based on the operation signal output by the short-circuit detection gate circuit, and a charging current output from a current detector also installed on the distribution line, and each circuit is A short circuit detection display device comprising a power supply circuit that supplies a drive current, the short circuit detection circuit comprising a photocoupler that converts and outputs an analog signal output by a current detector into a digital signal when a short circuit current flows in a distribution line. , is configured to output a digitized short circuit current detection signal based on the analog signal, and connects the short circuit detection circuit to each current detector provided in each phase distribution line, and connects the power supply circuit to the current detector. The gist is that the short circuit detection circuit is connected to the connected current detector.

(Function) With the above configuration, when a short-circuit current that can trip a substation circuit breaker flows in any of the three-phase distribution lines, the photocoupler converts the analog signal output from the current detector into a digital signal and outputs the short circuit. The detection circuit outputs a digitized short circuit current detection signal. When the circuit breaker of the substation trips, the no-voltage detection circuit detects the no-voltage state of the distribution line via the current detector and outputs a no-voltage detection signal.

The short-circuit detection gate circuit outputs an operation signal when both the short-circuit current detection signal from the short-circuit detection circuit and the no-voltage detection signal from the no-voltage detection circuit are input, and the short-circuit indicator outputs an operation signal from the short-circuit detection gate circuit. The short circuit display operates based on the operation signal output by.

In addition, drive current is supplied to each of the above circuits from the power supply circuit, and the short circuit detection circuit is equipped with a photocoupler, so the power supply circuit is connected to the current transformer to which the short circuit detection circuit is connected. It is considered possible.

(Example) Hereinafter, an example in which the present invention is embodied in a short circuit/ground fault direction detection/display device will be described with reference to FIGS. 1 to 6.

(Detector) In FIG. 1, first, the detector of the short circuit/ground fault direction detection/display device 1 will be explained. second and third current transformer CT1,
CT2, CT3, a zero-sequence current transformer (hereinafter referred to as ZCT) 2 as a zero-sequence current detector that detects the zero-sequence current flowing in the distribution line L, and a zero-sequence voltage detector (hereinafter referred to as
(referred to as ZPD) 3 is provided.

Said first, second and third current transformers CT1, CT
2. CT3 is designed to output a transformed current from its secondary side when a short-circuit current flows through the distribution line.

In addition, P9 and P1 are the output terminals of ZCT2,
P11 and P12 are output terminals of ZPD3.

(Control circuit) The control circuit is roughly divided into a short circuit detection section, a no-voltage detection section, a short circuit discrimination section, a short circuit indicator drive section, a phase comparison discrimination circuit, a ground fault direction indicator drive section, a power supply section, and a time limit section. It is configured.

Each part will be described in detail below with reference to the drawings.

Short Circuit Detection Section The short circuit detection section is composed of first, second, and third short circuit detection circuits Xa, Xb, and Xc.

First, the first short circuit detection circuit Xa will be explained.

A full-wave rectifier 6 as a rectifier circuit is connected between both terminals connected to the first current transformer CT1 via chiyoke coils 5a and 5b.
Further, a surge absorber 7 as a surge absorption circuit is connected between both terminals.

A parallel circuit including a smoothing capacitor C1 and a resistor R1 is connected between the positive and negative terminals of the full-wave rectifier 6. Similarly, between the positive and negative terminals of the full-wave rectifier 6, there is a resistor R2, a selector switch S,
Parallel circuit of resistor R3 and resistor R4 with different resistance values and light emitting diode of photocoupler PC
A series circuit consisting of an LED is connected. By selectively connecting the changeover switch S to the resistor R3 or resistor R4 side, the short circuit ground fault direction detection display device 1 can be attached to the distribution line L through which different steady load currents flow. There is.

Between the output terminal P13 (plus terminal) of the power supply circuit Z (to be described later) and the minus terminal of the full-wave rectifier 6, there is connected the emitter-collector of the switching transistor Tr1 and a resistor R5 via the collector.
A series circuit with is connected. A diode D1 is connected to the collector of the switching transistor Tr1. A resistor R6 and a photocoupler PC are connected between the negative terminal of the full-wave rectifier 6 and the base terminal of the switching transistor Tr1.
The emitter and collector of the phototransistor PTr are connected to each other, and a resistor R7 is connected between the positive terminal of the resistor R6 and the output terminal P13.

Therefore, when a short-circuit current flows through the distribution line L, the first current transformer CT1 outputs a transformed current based on the short-circuit current, and the full-wave rectifier 6 performs full-wave rectification of the transformed current. The photocoupler PC receives the full-wave rectified analog signal and outputs it digitally using a light emitting diode LED and a phototransistor PTr. Furthermore, when the level of the digital signal applied to the base terminal is a predetermined value, the switching transistor Tr1 is turned on and outputs a short circuit current detection signal.

A current discrimination switching circuit 50 in FIG. 2 is constituted by the resistors R1 to R7, photocoupler PC, switching transistor Tr1, and diode D1.

The surge absorption circuit 7, the rectifier circuit 6, and the current discrimination switching circuit 50 constitute a first short circuit detection circuit Xa.

Since the second short-circuit detection circuit Xb and the third short-circuit detection circuit Xc are configured similarly to the first short-circuit detection section, the same configurations are given the same reference numerals and the explanation thereof will be omitted. Note that a resistor R14 is connected between the resistor R1 and the negative terminal of the full-wave rectifier 6 in the third short circuit detection circuit Xc.

No-voltage detection part Next, the no-voltage detection section will be explained.

In the third short circuit detection circuit Xc, a resistor R1
A diode array Da is connected between the negative terminal of the full-wave rectifier 6 and the negative terminal of the full-wave rectifier 6, and resistors R15 and R16 are connected between the positive terminal side of the diodes that constitute the diode array Da and the negative terminal of the full-wave rectifier 6. A series circuit of C2 and a parallel circuit of a capacitor C2 for noise prevention are connected.

Further, a resistor R17 and a collector/emitter of a transistor Tr2 are connected between an output terminal P13 of a power supply circuit to be described later and a negative terminal of a full-wave rectifier 6.
The positive terminal of the resistor R16 is connected to the same transistor.
Connected to the base terminal of Tr2. Further, a capacitor C3 is connected between both terminals of the resistor R16.

The input terminal of the inverter In1 is connected to the collector of the transistor Tr2, and the input terminal of the inverter In1 is connected to the collector of the transistor Tr2.
A knot circuit 13 is connected to the output terminal of.

When the distribution line L is in a steady state, the voltage between the diode arrays is divided between the resistors R15 and R16, and the transistor Tr2 becomes conductive by applying the voltage of the resistor R16 to its base terminal.
The signal between the diode arrays is voltage amplified and applied to the input terminal of the inverter In1.

Therefore, the collector of the transistor Tr2
Since the voltage between the emitters becomes 0, the inverter In
A signal corresponding to a logical value 0 is applied to an input terminal of 1, and a signal corresponding to a logical value 1 is output from the output terminal. Then, the knot circuit 13 outputs a signal corresponding to the logical value 0 based on the signal corresponding to the logical value 1.

In response, when the circuit breaker at the substation trips due to a short circuit accident on the distribution line L, the voltage across the diode array becomes zero, so the transistor Tr
The voltage of the resistor R16 (ie, no voltage) is applied to the base terminal of the transistor Tr2, and the transistor Tr2 is turned off. Then, since the transistor Tr2 is off, the inverter In1
A voltage between the collector and emitter of the transistor Tr2, that is, a signal corresponding to a logic value of 1 is applied to the transistor Tr2. Therefore, a signal corresponding to the logic value 0 is output from the output terminal of the inverter In1, and the knot circuit 13 rectangles the waveform based on the signal corresponding to the logic value 0, and converts the signal corresponding to the logic value 1 (no voltage) into a rectangular waveform. detection signal).

The diode array Da, resistors R15 to R1
7. Capacitors C2, C3, transistor Tr2
A no-voltage detection circuit 51 is configured.

Furthermore, the inverter In1 and the knot circuit 13 constitute a second waveform manipulation circuit 52, and both circuits 51 and 52 constitute a no-voltage detection section.

Short circuit determination section Next, the first to third short circuit detection circuits Xa, Xb,
A description will be given of the short-circuit detection section which inputs the short-circuit detection signal, which is a digital signal outputted from Xc, and the no-voltage detection signal from the no-voltage discrimination circuit 51 via the second waveform manipulation circuit 52.

The negative terminals of the diodes D1 in each of the short circuit detection circuits Xa, Xb, and Xc are connected to each other, and the negative terminals of the diodes D1 are connected to each other for short circuit detection via an AND circuit 8 as a first waveform manipulation circuit and a resistor R9. It is connected to one input terminal of an AND circuit 9 as a gate circuit. A parallel circuit of a resistor R8 and a capacitor C4 is connected between the negative terminal of the diode D1 and the negative terminal of the full-wave rectifier 6, and a logic value 1 is applied to the input terminal of the AND circuit 8 for a predetermined period of time due to the time constant of the CR circuit. A voltage is applied to the resistor R8.

A signal memory circuit 53 is constituted by the resistor R8 and capacitor C4.

Between the output terminal P13 (plus terminal) of the power supply circuit Z and the minus terminal of the full-wave rectifier 6, a series circuit consisting of a resistor R10 connected via the collector/emitter and emitter of the switching transistor Tr3 is connected. A capacitor C5 is connected in parallel between both terminals of R10. The emitter terminal of the switching transistor Tr3 is connected to the gate terminal of a thyristor SCR1, which will be described later, so that a voltage of a resistor R10 is applied thereto.

And the switching transistor Tr3
The base terminal of the AND circuit 8 is connected to the output terminal of the AND circuit 8 via R11. Moreover, the resistance R
A resistor R12 is connected between the negative terminal of the full-wave rectifier 11 and the negative terminal of the full-wave rectifier 6, and the voltage of the resistor R12 is applied to the base terminal of the switching transistor Tr3.

Therefore, when a signal corresponding to a logical value 1 is input to the AND circuit 8 for a predetermined period of time, the AND circuit 8 receives a signal corresponding to the logical value 1 (short circuit current detection) which is a rectangular wave in response to the logical value 1. signal) and circuit 9
Output to. The AND circuit 9 operates when a signal corresponding to a logic value 1 (non-voltage detection signal) from the no-voltage detection circuit 51 is applied while a signal corresponding to a logic value 1 from the AND circuit 8 is applied. , and output a first switch signal corresponding to a logical value of 1 based on both signals. Then, the voltage of the resistor R12 is applied to the base terminal of the switching transistor Tr3 based on the first switch signal, so that the switching transistor Tr3 is turned on (conducted).

The signal memory circuit 53, the AND circuit (first waveform manipulation circuit) 8, and the AND circuit (gate circuit for short circuit detection) 9 constitute a short circuit determination section.

Short circuit indicator drive Next, the driving section of the short circuit indicator Ha will be explained.

A diode D2, a charging resistor R13, and a capacitor C6 as a driving power source are connected between the output terminal P13 (plus terminal) of the power supply circuit Z (described later) and the minus terminal of the full-wave rectifier 6 in the first short circuit detection circuit Xa.
are connected in series to constantly charge the capacitor C6. Between the positive terminal of the capacitor C6 and the negative terminal of the full-wave rectifier 6 of the first detection circuit Xa are the anode and cathode of the thyristor SCR1, the diode D3, and the short circuit indicator
A series circuit of a set terminal 10 and a common terminal 11 of Ha is connected. Further, a driving flywheel diode D4 is connected between the set terminal 10 and the common terminal 11 of the short circuit indicator Ha.

Therefore, when the switching transistor Tr3 turns on (conducts), a voltage is applied to the capacitor C5 and the resistor R10. As a result, from capacitor C5 and resistor R10 the thyristor SCR1
By applying a voltage to the gate terminal of the thyristor,
It is designed to make SCR1 conductive. and,
Due to conduction of thyristor SCR1, capacitor C
6 is discharged, and a short circuit display drive current is output to the short circuit display Ha.

The diode D2, the charging resistor R13, and the capacitor C6 constitute a display driving power supply charging circuit 54, and the resistor R10, the capacitor C5, and the thyristor SCR1 constitute a first switching circuit 55 (see FIG. 2). ing.

A resistor R18 and a series circuit of the collector and emitter of the switching transistor Tr4 are connected between the output terminal P13 (plus terminal) of the power supply circuit Z (described later) and the minus terminal of the full-wave rectifier 6 in the first short circuit detection circuit Xa. There is. The base terminal of the switching transistor Tr4 and the thyristor
Diode D5 is connected between the cathode terminal of SCR1,
A series circuit of resistor R19 is connected. Furthermore, a resistor R20 is connected between the negative terminal of the resistor R19 and the negative terminal of the full-wave rectifier 6, so that the voltage of the resistor R20 is applied to the base terminal of the switching transistor Tr4.

Between the output terminal P13 (plus terminal) of the power supply circuit Z (to be described later) and the minus terminal of the full-wave rectifier 6 in the first short-circuit detection circuit Xa, the emitter and collector of the switching transistor Tr5 and the resistor R21 are connected.
series circuit is connected. Further, a capacitor C7 is connected between both terminals of the resistor R21, and the positive terminal of the capacitor C7 is connected to a clear terminal 22 of an IC 14 of a time limit circuit T, which will be described later, via a diode D13.

A resistor R22 is connected between the base terminal of the switching transistor Tr5 and the collector terminal of the switching transistor Tr4, and controls the voltage between the collector and emitter of the switching transistor Tr4.
The voltage is applied to the base terminal of No. 5.

Therefore, when the thyristor SCR1 is not conductive, the switching transistors Tr4,
And the switching transistor Tr5 is in an off state. When the thyristor SCR1 becomes conductive, the voltage of the resistor R20 is applied to the base terminal of the switching transistor Tr4, so that the switching transistor Tr4 is turned on (conducted). Then, the switching transistor
The potential at the base terminal of Tr5 decreases, and the switching transistor Tr5 turns on. Then,
A clear control signal SG1 is output from the capacitor C7 and the resistor R21 to the clear terminal 22 of the IC14 of the time limit circuit T1 according to the time constant of the CR circuit.

A voltage amplification circuit 56 is constituted by the diode D5, resistors R18 to R22, and switching transistors Tr4 and Tr5.

The positive terminal of the capacitor C6 and the short circuit indicator
A thyristor SCR2 is connected between the reset terminal 12 of Ha.
A series circuit of the anode and cathode of and a diode D6 are connected. Further, a return drive flywheel diode D7 is connected between the reset terminal 12 and the common terminal 11 of the short circuit indicator Ha.
A Schmitt trigger circuit SC of a time limit circuit T to be described later is connected to the gate terminal of the thyristor SCR2 via a resistor R23 and a diode D8. Furthermore, a resistor R2 is connected between the gate terminal of the thyristor SCR2 and the negative terminal of the full-wave rectifier 6.
4 and a parallel circuit of capacitor C8 are connected.

Therefore, when the display return signal Sig4 is output from the Schmitt trigger circuit SC, a voltage is applied to the capacitor C8 and the resistor R24. the result,
From capacitor C8 and resistor R24 to the thyristor
A voltage is applied to the gate terminal of SCR2 to make the thyristor SCR2 conductive. As the thyristor SCR2 becomes conductive, the charge in the capacitor C6 is discharged, and a return drive current is output to the short circuit indicator Ha.

Said resistor R24, capacitor C8, thyristor
A switching circuit 57 (see FIG. 2) is constituted by the SCR2.

Short Circuit Indicator The short circuit indicator Ha will now be explained in detail with reference to FIGS. 4 to 6.

The short circuit indicator Ha is composed of a plurality of magnetic reversal indicators. In one magnetic reversal display, a disk 15 whose both ends are magnetized to N and S poles is connected to a rotating shaft 16.
A round bar-shaped stator 17 is formed to have a magnetic pole part 17a corresponding to the south pole of the disk 15 and a magnetic pole part 17b corresponding to the north pole of the disk 15. Note that the stator 17 is preferably formed of a material with low coercive force. Both ends of the magnetic pole parts 17a and 17b are connected to the common terminal 11 and the set terminal 10 so that the magnetic pole parts 17a and 17b are magnetized with the same polarity with respect to the magnetic poles at both ends of the disk 15 in the state shown in FIG. A driving coil 18 is wound thereon.

Also, adjacent to the drive coil 18 and between the two magnetic pole portions 17a and 17b, there are magnetic pole portions 17a and 17b.
A return drive coil 19 connected to the common terminal 11 and the reset terminal 12 is wound so that it is magnetized to the same polarity as the magnetic poles at both ends of the disk 15 in the state shown in FIG.

Front surface 15a and back surface 15b of the disk 15
Labels of different colors (in this embodiment, the front side 15a is black and the back side 15b is red) are displayed on the .

The drive coil 18 and return drive coil 19 of each magnetic reversal display are connected in parallel to each other (see FIG. 6).

Therefore, when a short circuit display drive current flows through the short circuit display Ha through the set terminal 10, each drive coil 18 is excited, and the magnetic pole portion 17 is energized as shown in FIG.
a is magnetized as an S pole, and the magnetic pole part 17b is magnetized as an N pole, and the N pole of each disk 15 is magnetized as the magnetic pole part 17a (S pole).
Then, the S pole is reversely rotated so that it faces the magnetic pole part 17b (N pole), and the back surface 15 of each disk 15 is rotated.
The signs attached to b are displayed all at once to the outside (short-circuit display).

In addition, on the contrary, reset terminal 12 is connected to the short circuit indicator Ha.
When the return drive current flows through the return drive coils 19, each return drive coil 19 is excited, and as shown in FIG. The pole is the magnetic pole part 17a
(N pole) and the S pole thereof faces the magnetic pole part 17b (S pole), and the marks attached to the surface 21a of each disk 15 are constantly displayed to the outside all at once.

Phase comparison discrimination circuit Next, the phase comparison and discrimination circuit 20 will be explained.

The phase comparison and discrimination circuit 20 is connected to the output terminals P9 and P10 of the ZCT2, and also connected to the output terminals P9 and P10 of the ZCT2.
is connected to output terminals P11 and P12 of.

In FIG. 2, the in-phase comparison and discrimination circuit 11 is
A zero-sequence current detection signal outputted via the surge absorption circuit 58 when the ZCT2 detects a zero-sequence current;
When the zero-sequence voltage detection signal that is output via the surge absorption circuit 59 when the ZPD 3 detects the zero-sequence voltage is input, the phase comparison circuit 60 compares the phases of the zero-sequence current and zero-sequence voltage based on both signals. I'm starting to do it.

Then, as a result of the phase comparison of the phase comparison circuit 60, the phase discrimination circuit 61 determines that if the phase of the zero-sequence current is close to leading by 0 to 110 degrees with respect to the phase of the zero-sequence voltage as a reference, the ground fault fault point is on the right side of the display. It is designed to output a control signal. On the contrary, when the phase comparison of the phase comparison circuit 60 shows that the phase of the zero-sequence current is shifted by 180 degrees, the phase discrimination circuit 61 determines that the ground fault point is on the left side of the display and outputs a control signal. ing.

Further, the switching circuit 62 is turned on based on the control signal from the phase discrimination circuit 61. Further, the signal memory circuit 63 responds to the ON operation of the switching circuit 62, and outputs a judgment signal corresponding to the logical value 1 from the right display output terminal P14 for a certain period of time when the phase of the zero-sequence current is close to leading by 0 to 110 degrees. It is now output. In addition, the signal memory circuit 63 responds to the ON operation of the switching circuit 62, and when the phase of the zero-sequence current is 180 degrees out of phase, the signal memory circuit 63 assumes that the ground fault point is on the left side of the display and outputs a logical value from the left display output terminal P15. A determination signal corresponding to 1 is output for a certain period of time.

The surge absorption circuits 58 and 59, the phase comparison circuit 60, the phase discrimination circuit 61, and the switching circuit 62
and the signal memory circuit 63 constitute the phase comparison and discrimination circuit 20.

Driving unit of ground fault direction indicator The input terminal of an AND circuit 21 as a gate circuit for ground fault detection is connected to the right display output terminal P14, and a judgment signal corresponding to a logical value of 1 is input from the right display output terminal P14. Then, a second switch signal corresponding to the logical value 1 is applied from the output terminal.

A series circuit of a diode D9, a charging resistor R25, and a capacitor C9 as a drive power source is connected between the output terminal P13 (plus terminal) of the power supply circuit Z and the ground terminal P16, so that the capacitor C9 is constantly charged.

The diode D9, charging resistor R25, and capacitor C9 constitute a display drive power supply charging circuit 64 in FIG.

A series circuit of a thyristor SCR3 and a diode D10 is connected between the positive terminal of the capacitor C9 and the set terminal 10 of the right direction indicator Hb1 that displays the right direction, and the negative terminal of the capacitor C9 is connected to the common terminal 11 of the right direction indicator Hb1. It is connected to the. Further, a driving flywheel diode D11 is connected between the set terminal 10 and the common terminal 11 of the right direction indicator Hb1.

A series circuit of a resistor R26 connected to the collector and emitter of a switching transistor Tr6 via the emitter is connected between the output terminal P13 (plus terminal) of the power supply circuit Z and the ground terminal P16. A capacitor C is connected to both terminals of the resistor R26.
10 are connected in parallel. The switching transistor Tr6 has its emitter terminal connected to the gate terminal of the thyristor SCR3, and its base terminal connected to the output terminal of the AND circuit 21 via a resistor R27. Further, a resistor R28 is connected between the negative terminal of the resistor R27 and the ground terminal P16, and applies a voltage to the base terminal of the switching transistor Tr6.

Therefore, when the second switch signal corresponding to the logical value 1 is output from the AND circuit 21, the resistor R
A voltage of 28 is applied to the base terminal of the switching transistor Tr6. As a result, the switching transistor Tr6 is turned on (conducted),
A voltage is applied to the capacitor C10 and the resistor R26. As a result, capacitor C10 and resistor R2
A voltage is applied from 6 to the gate terminal of the thyristor SCR3 to make the thyristor SCR3 conductive.
As the thyristor SCR3 becomes conductive, the charge in the capacitor C9 is discharged, and a ground fault display drive current as a ground fault direction display signal is outputted to the right direction indicator Hb1.

A second switching circuit 65 in FIG. 2 is constituted by the resistors R26 to R28, the switching transistor Tr6, the capacitor C10, and the thyristor SCR3.

In addition, a resistor R2 is connected between the output terminal P13 (positive terminal) of the power supply circuit Z to be described later and the earth terminal P16.
9. A series circuit of the collector and emitter of the switching transistor Tr7 is connected. A series circuit of a diode D12 and a resistor R30 is connected between the base terminal of the switching transistor Tr7 and the cathode terminal of the thyristor SCR3. Furthermore, a resistor R31 is connected between the negative terminal of the resistor R30 and the ground terminal P16, and the voltage of the resistor R31 is applied to the base terminal of the switching transistor Tr7.

A series circuit consisting of the emitter and collector of a switching transistor Tr8 and a resistor R32 is connected between an output terminal P13 (plus terminal) of a power supply circuit Z (to be described later) and a ground terminal. Furthermore, the resistance R
A capacitor C11 is connected between both terminals of the capacitor C11, and a clear terminal 22 of an IC14 of a time limit circuit T, which will be described later, is connected to the positive terminal of the capacitor C11 via a diode D14.

A resistor R33 is connected between the base terminal of the switching transistor Tr8 and the collector terminal of the switching transistor Tr7, and controls the voltage between the collector and emitter of the switching transistor Tr7.
The voltage is applied to the base terminal of No. 8.

Therefore, when the thyristor SCR3 is not conductive, the switching transistor Tr7 and the switching transistor Tr8 are in an off state. When the thyristor SCR3 becomes conductive, the voltage of the resistor R31 is applied to the base terminal of the switching transistor Tr7, so that the switching transistor Tr7 turns on (conducts).
do.

Then, the potential at the base terminal of the switching transistor Tr8 decreases, and the switching transistor Tr8 turns on. Then, the clear control signal SG2 is output from the capacitor C11 and the resistor R32 to the IC of the time limit circuit T by the time constant of the CR circuit.
The signal is output to the clear terminal 22 of 14.

The diode D12, the resistors R29 to R33,
An output voltage amplification circuit 66 is constituted by switching transistors Tr7 and Tr8.

A diode D20, a charging resistor R43, and a capacitor C as a return drive power source are connected between the output terminal P13 (positive terminal) of the power supply circuit Z and the ground terminal P16.
15 series circuits are connected, and the capacitor C1 is always connected.
5 is now charged.

The diode D20, the charging resistor R43, and the capacitor C15 constitute a recovery drive power supply charging circuit 67 in FIG.

A series circuit consisting of the anode and cathode of the thyristor SCR5 and a diode D21 is connected between the positive terminal of the capacitor C15 and the reset terminal 12 of the right direction indicator Hb1. In addition, the reset terminal 12 and common terminal 1 of the right direction indicator Ha
Between 1 and 1 is a flywheel diode D for return drive.
22 are connected. Said thyristor SCR5
The Schmitt trigger circuit SC of the time limit circuit T, which will be described later, is connected to the gate terminal of the resistor R23 and the diode D.
23. Furthermore, the gate terminal of the thyristor SCR5 and the ground terminal P16
A parallel circuit of a resistor R44 and a capacitor C16 is connected between them.

Therefore, when the display return signal Sig4 is output from the Schmitt trigger circuit SC, a voltage is applied to the capacitor C16 and the resistor R44. As a result, a voltage is applied from the capacitor C16 and the resistor R44 to the gate terminal of the thyristor SCR5, thereby making the thyristor SCR5 conductive. Then, due to conduction of thyristor SCR5,
The charge in the capacitor C15 is discharged, and a return drive current is output to the right direction indicator Hb1.

A switching circuit 68 in FIG. 2 is constituted by the resistor R44, capacitor C16, and thyristor SCR5.

Further, the positive terminal of the capacitor C11 is connected to the diode D24 to the gate terminal of a thyristor SCR6 for return drive for the left direction indicator Hb2, which will be described later.
connected via. Then, when the switching transistor Tr8 is turned on, a gate trigger voltage is applied that turns on the thyristor SCR6.

Similarly, the input terminal of an AND circuit 23 serving as a gate circuit for ground fault detection is connected to the left display output terminal P15. That is, when this AND circuit 23 receives a determination signal corresponding to a logical value 1 from the left display output terminal P15, it applies a second switch signal corresponding to a logical value 1 from its output terminal.

A diode D15, a charging resistor R34, and a capacitor C12 as a driving power source are connected between the output terminal P13 (positive terminal) of the power supply circuit Z and the ground terminal P16.
are connected in series to constantly charge the capacitor C12.

The diode D15, charging resistor R34, and capacitor C12 constitute a display drive power supply charging circuit 69 in FIG.

A series circuit of a thyristor SCR4 and a diode D16 is connected between the positive terminal of the capacitor C12 and the set terminal 10 of the left direction indicator Hb2 which displays the left direction, and the negative terminal of the capacitor 12 is connected to the common terminal 11 of the left direction indicator Hb2. It is connected to the. Further, a driving flywheel diode D17 is connected between the set terminal 10 and the common terminal 11 of the left direction indicator Hb2.

A series circuit including a resistor R35 connected via the collector-emitter and emitter of a switching transistor Tr9 is connected between the output terminal P13 (plus terminal) of the power supply circuit Z and the earth terminal P16. A capacitor C is connected to both terminals of the resistor R35.
13 are connected in parallel. The switching transistor Tr9 has its emitter terminal connected to the gate terminal of the thyristor SCR4, and its base terminal connected to the output terminal of the AND circuit 23 via a resistor R36. Further, a resistor R37 is connected between the negative terminal of the resistor R36 and the ground terminal P16, and applies a voltage to the base terminal of the switching transistor Tr9.

Therefore, when the second switch signal corresponding to the logical value 1 is output from the AND circuit 23, the voltage of the resistor R37 is applied to the base terminal of the switching transistor Tr9 based on the second switch signal. As a result, the switching transistor Tr9 is turned on (conducted), and a voltage is applied to the capacitor C13 and the resistor R35. As a result, a voltage is applied from the capacitor C13 and the resistor R35 to the gate terminal of the thyristor SCR4,
The same thyristor SCR4 is made conductive. Then, due to conduction of thyristor SCR4, capacitor C1
2 is discharged and the left direction indicator Hb2
A ground fault display drive current is output as a ground fault direction display signal.

A second switching circuit 70 in FIG. 2 is constituted by the resistors R35 to R37, the switching transistor Tr9, the capacitor C13, and the thyristor SCR4.

In addition, a resistor R3 is connected between the output terminal P13 (positive terminal) of the power supply circuit Z to be described later and the earth terminal P16.
8. A series circuit of the collector and emitter of the switching transistor Tr10 is connected. A series circuit of a diode D18 and a resistor R39 is connected between the base terminal of the switching transistor Tr10 and the cathode terminal of the thyristor SCR4. Furthermore, a resistor R40 is connected between the negative terminal of the resistor R39 and the ground terminal P16, and the voltage of the resistor R40 is applied to the base terminal of the switching transistor Tr10.

Between the output terminal P13 (positive terminal) of the power supply circuit Z (to be described later) and the ground terminal, the emitter and collector of the switching transistor Tr11 and the resistor R41 are connected.
series circuit is connected. Further, a capacitor C14 is connected between both terminals of the resistor R41, and the positive terminal of the capacitor C14 is connected to a clear terminal 22 of an IC14 of a time limit circuit T, which will be described later, via a diode D19.

The base terminal of the switching transistor Tr11 and the switching transistor Tr10
A resistor R42 is connected between the collector terminals of the switching transistor Tr10, and applies the voltage between the collector and emitter of the switching transistor Tr10 to the base terminal of the switching transistor Tr11.

Therefore, when the thyristor SCR4 is not conductive, the switching transistors Tr10,
The switching transistor Tr11 is in an off state. When the thyristor SCR4 becomes conductive, the voltage of the resistor R40 is applied to the base terminal of the switching transistor Tr10, so that the switching transistor Tr10 is turned on.

Then, the potential at the base terminal of the switching transistor Tr11 decreases, and the switching transistor Tr11 is turned on. Then, the clear control signal SG3 is output from the capacitor C14 and the resistor R41 to the time limit circuit T by the time constant of the CR circuit.
output to the clear terminal 22 of the IC 14.

The diode D18, the resistors R38 to R41,
A voltage amplification circuit 71 is constituted by switching transistors Tr10 and Tr11.

A diode D25, a charging resistor R45, and a capacitor C as a return drive power source are connected between the output terminal P13 (positive terminal) of the power supply circuit Z and the ground terminal P16.
17 series circuits are connected, and the capacitor C1 is always connected.
7 is now charging.

The diode D25, the charging resistor R45, and the capacitor C17 constitute the recovery drive power supply charging circuit 72 in FIG.

A series circuit consisting of the anode and cathode of the thyristor SCR6 and a diode D26 is connected between the positive terminal of the capacitor C17 and the reset terminal 12 of the left direction indicator Hb2. Further, a return driving flywheel diode D27 is connected between the reset terminal 12 and the common terminal 11 of the left direction indicator Hb2. Said thyristor SCR
A Schmitt trigger circuit SC of a time limit circuit T, which will be described later, is connected to the base terminal of 6 through a resistor R23 and a diode D28. Furthermore, the gate terminal of the thyristor SCR6 and the ground terminal P1
6, a parallel circuit of a resistor R46 and a capacitor C18 is connected.

Therefore, when the display return signal Sig4 is output from the Schmitt trigger circuit SC, a voltage is applied to the capacitor C18 and the resistor R46. As a result, a voltage is applied from the capacitor C18 and the resistor R46 to the gate terminal of the thyristor SCR6, making the thyristor SCR6 conductive. Then, due to conduction of thyristor SCR6,
The charge in the capacitor C17 is discharged, and a return drive current is output to the left direction indicator Hb2.

A switching circuit 73 in FIG. 2 is constituted by the resistor R46, capacitor C18, and thyristor SCR6.

Further, the positive terminal of the capacitor C14 is connected to the gate terminal of a thyristor SCR5 for the right direction indicator Hb1, which will be described later, via a diode D29. and switching transistor
When Tr11 turns on, thyristor SCR5
A gate trigger voltage is applied to turn on the gate.

Ground fault direction indicator The pair of right direction indicator Hb1 and left direction indicator Hb2 that constitute the ground fault direction indicator are the short circuit indicators.
It has the same configuration as Ha, and both displays Hb1,
When a ground fault display drive current flows through Hb2 through the set terminal 10, each drive coil (not shown) is energized, so that the marks attached to the back of each disk are displayed simultaneously to the outside (earth fault direction Is displayed.

Conversely, when a return drive current flows through the reset terminals 12 to both indicators Hb1 and Hb2, each return drive coil (not shown) is energized, so that the mark attached to the surface of each disk is are constantly displayed all at once.

time limit part Next, the time limit circuit T will be explained.

IC14 has a resistor R50, a capacitor C20,
An oscillation circuit 74 consisting of a resistor R51 is connected and
The IC 14 is adapted to divide the number of oscillations of its oscillation circuit 74.

Between the output terminal P13 (plus terminal) of the power supply circuit Z and the minus terminal of the IC14, there are connected the collector and emitter of the switching transistor Tr12,
A series circuit with a resistor R52 connected via an emitter is connected. Note that the capacitor C21 connected to both terminals of the resistor R52 is for noise prevention.

The output terminal of IC14 is connected to the base terminal of the switching transistor Tr12 via a resistor R53.
12 base terminal and the third short circuit detection circuit Xc
A resistor R54 is connected between the negative terminals of the full-wave rectifier 6, and the voltage of the resistor R54 is applied to the base terminal of the switching transistor Tr12.

In addition, a resistor R is connected between the output terminal P13 (positive terminal) of the power supply circuit Z and the negative terminal of the IC14.
55 and the collector/emitter of the switching transistor Tr13 are connected in series.
A capacitor C22 is connected between the positive terminal of the resistor R52 and the base terminal of the switching transistor Tr13, and a capacitor C22 is connected between the base terminal of the switching transistor Tr13 and the negative terminal of the full-wave rectifier 6 in the third short circuit detection circuit Xc. is connected to resistor R56. A differentiation circuit is constituted by the capacitor C22 and the resistor R56.

Note that the diodes D13, D19, D14
A resistor R57 is connected between the negative terminal of the full-wave rectifier 6 in the third short-circuit detection circuit Xc.
is connected.

The switching transistors Tr12 and Tr1
3. Capacitor C21, resistor R23, resistor R53
.about.R56 and the Schmitt trigger circuit SC constitute a display return signal generation circuit 75 in FIG.

When this IC 14 receives clear control signals Sig1, Sig2, and Sig3 from the respective circuits, it clears the division of the number of oscillations of the oscillation circuit and starts re-dividing the number of oscillations. When the IC 14 is divided into a predetermined number of parts, that is, after a predetermined time has elapsed, a time-up signal is applied from its output terminal for a predetermined time via the resistor R53. Then, the resistance R
The voltage of 54 is applied to the switching transistor Tr12.
Since the voltage is applied to the base terminal of the switching transistor Tr12, the switching transistor Tr12 is turned on (conducted) while the time-up signal is applied, and a voltage is applied to the differentiation circuit of the capacitor C22 and the resistor R56.

As a result, since a voltage is applied from the differentiating circuit to the gate terminal of the switching transistor Tr13 at the rise of the time-up signal for a predetermined period of time, the switching transistor Tr13 is turned on for the time constant of the capacitor C22 and the resistor R56 ( conduction). Then, the switching transistor Tr13 is turned on.
Schmitt trigger circuit based on off operation
SC waveforms the signal applied to the same Schmitt trigger circuit SC, and each display Ha, Hb1, Hb2
The display return signal Sig4 is outputted.

Power Supply Section Next, the power supply section will be explained. The power supply section is composed of a power supply circuit Z and a power supply voltage check circuit 78.

The power supply circuit Z is provided in the full-wave rectifier 6 in the third short-circuit detection circuit Xc. That is,
A series circuit of a transistor Tr14, a diode D30, and a rechargeable battery B is connected between both terminals of the diode array Da. Further, a resistor R58 is connected between the collector terminal and the base terminal of the transistor Tr14, and a Zener diode ZD is connected between the base terminal of the transistor Tr14 and the negative terminal of the full-wave rectifier 6.

The diode array Da constitutes a first constant voltage circuit 76 in FIG. 2, and a second constant voltage circuit 77 is constituted by a resistor R58, a transistor Tr14, and a Zener diode ZD.

This power supply circuit Z further stabilizes the forward voltage across the diode array Da2 using the transistor Tr14, the Zener diode ZD, etc., and charges the battery B.

When a steady load current is flowing through the distribution line L, the backup battery B is not consumed, and the load current is used to supply drive current to the various parts. When the substation circuit breaker trips and load current no longer flows through the distribution line L, the backup battery B supplies the necessary drive current to each part from the output terminal P13.

The power supply voltage check circuit 78 will be explained.

A series circuit of a resistor R59 and the collector-emitter of a transistor Tr15 is connected between both terminals of the battery B, and a resistor R60 and a resistor R
61 series circuits are connected. A capacitor C23 is connected to both terminals of the resistor R61, and the positive terminal of the resistor R61 is connected to the base terminal of the transistor Tr15 so that the voltage of the resistor R61 is applied to the base terminal of the transistor Tr15. It's summery.

A diode D3 is connected between both terminals of the battery B.
1. Resistor R62, battery check indicator Hc common terminal 28/set terminal 29, diode D3
2 and the collector and emitter of the switching transistor Tr16 are connected. Furthermore, a freewheel diode D33 is connected between the set terminal 29 and the common terminal of the battery check indicator Hc.

A series circuit consisting of an inverter In2, a NOT circuit 25, a capacitor C24, a resistor R63, an AND circuit 26, and a resistor R64 is connected between the collector terminal of the transistor Tr15 and the base terminal of the switching transistor Tr16. A resistor R65 is connected between the positive terminal of the resistor R63 and the negative terminal of the battery B, and
A resistor R6 is connected between the base terminal of the switching transistor Tr16 and the negative terminal of the battery B.
6 is connected.

Therefore, when the battery B holds a predetermined voltage, the transistor Tr15 is turned on because the voltage divided by the resistor R61 is applied to its base terminal. In this state, inverter In2
A signal corresponding to a logical value of 0 is input to. Then, a signal corresponding to the logical value 1 is applied from the inverter In2 to the not circuit 25, and the not circuit 25
Based on the signal corresponding to the logical value 1, the signal corresponding to the logical value 0 is connected to the capacitor C24 and the resistor R6.
5, apply to R63. The AND circuit 26 is
Input the signal corresponding to the logic value 0 from the CR circuit,
Based on the signal, a signal corresponding to the logical value 0 is applied to the base terminal of the switching transistor Tr16.
16 is in the off state.

On the other hand, when the battery B becomes lower than the predetermined voltage, the base terminal of the transistor Tr15 is turned off because the predetermined base voltage is not applied to the base terminal. Then, a signal corresponding to the logical value 1 is input to the inverter In2, and based on that signal, the inverter In2 applies a signal corresponding to the logical value 0 to the not circuit 25, and the not circuit 25 converts the logical value to 0. A signal corresponding to the logical value 1 is applied to the capacitor C24 and the resistors R65 and R63 based on the corresponding signal. The AND circuit 26 inputs the signal corresponding to the logic value 1 from the CR differentiation circuit, and based on that signal, applies the signal corresponding to the logic value 1 to the base terminal of the switching transistor Tr16. Tr16 is turned on.

A diode D34 and a switching transistor Tr1 are connected between the reset terminal 30 of the battery check indicator Hc and the negative terminal of the battery B.
7 collector emitters are connected.

Between the output terminal of the inverter In2 and the base terminal of the switching transistor Tr17,
A series circuit consisting of knot circuits 32 and 33, a capacitor C25, a resistor R67, an AND circuit 34, and a resistor R68 is connected, and a resistor R69 is connected between the positive terminal of the resistor R67 and the negative terminal of the battery B. Further, the switching transistor
A resistor R70 is connected between the base terminal of Tr17 and the negative terminal of battery B. and,
Battery check indicator Hc reset terminal 30
A freewheeling diode D3 is connected between the
5 is connected.

Therefore, the knot circuit 32 connects the inverter In2.
When a signal corresponding to a logical value 1 is input from the not circuit 32, the not circuit 32 inputs a signal corresponding to a logical value 0 to the not circuit 33 based on the signal corresponding to the logical value 1.
Based on the same signal, the NOT circuit 32 applies a signal corresponding to the logical value 1 to the capacitor C25 and the resistors R67 and R69. The AND circuit 34 inputs the signal corresponding to the logic value 1 from the CR differentiation circuit, and based on that signal, applies the signal corresponding to the logic value 1 to the base terminal of the switching transistor Tr16. Tr16 is turned on.

Conversely, when the inverter In2 outputs a signal corresponding to a logical value of 0 to the NOT circuit 32, the NOT circuit 32 outputs a signal corresponding to a logical value of 1 to the NOT circuit 33 based on the signal corresponding to the logical value of 0. , the same knot circuit 33 sends a signal corresponding to the logical value 0 to the capacitor C25 and the resistor R6 based on the same signal.
7, apply to R69. The AND circuit 34 is
Input the signal corresponding to the logic value 0 from the CR circuit,
Based on the signal, a signal corresponding to the logical value 0 is applied to the base terminal of the switching transistor Tr16.
16 is in the off state.

Battery Check Indicator The battery check indicator Hc has almost the same configuration as the short circuit indicator Ha, and when a display drive current flows through the common terminal 28 and the set terminal 29, a drive coil (not shown) is activated. By being excited, a mark attached to the back surface of the disk is displayed to the outside to indicate that the voltage of battery B has decreased.

Conversely, when a reset drive current flows through the common terminal 28 and the reset terminal 12, the battery check indicator Hc is activated by a return drive coil (not shown).
When B is excited, a mark attached to the surface of the disk is displayed to the outside, indicating that battery B maintains a predetermined voltage value.

Operation of the Embodiment The operation of the control circuit of the short-circuit/ground fault direction detection and display device configured as described above will be explained.

Now, when a steady load current is flowing through the distribution line L, the third current transformer is used in the power supply circuit Z.
A small amount of transformed current is output from the CT 3, and the transformed current is full-wave rectified by the full-wave rectifier 6 to charge the battery B of the power supply circuit Z. Furthermore, the power supply circuit Z is connected to capacitors C6, C9, and C as a driving power source for each circuit Xa,
12, C15, and C17.

Also, at this time, the first and second short circuit detection circuits Xa,
In Xb, the first and second current transformer CT
1. A small amount of metamorphic current is also output from CT2,
After the transformed current is full-wave rectified by the full-wave rectifier 6, most of it is consumed by the resistor R1, while in the third short-circuit detection circuit Xc, the resistor R1, resistor R14, and diode array Da consumed.

In this state, the current does not trip in the substation circuit breaker, and the thyristor in each circuit
SCR1 to thyristor SCR6 are in the off state.

In this state, for example, if a short circuit current that can trip a substation circuit breaker flows through the distribution line L to which the first current transformer CT1 is attached, the first current transformer
A transformed current is output from CT1 to the first short circuit detection circuit Xa. Then, this transformed current is passed through the full-wave rectifier 6
The full-wave rectified analog signal is input to the photocoupler PC, and digitally outputted by the light-emitting diode LED and the phototransistor PTr. Then, the switching transistor Tr1 is turned on when the level of the digital signal applied to the base terminal is equal to or higher than a predetermined value. As a result, the CR of resistor R8 and capacitor C4 is
Due to the time constant of the circuit, the voltage of the resistor R8 is applied to the AND circuit 8 for a predetermined period of time as a signal corresponding to a logical value of 1.

Therefore, the AND circuit 8 outputs a rectangular wave signal (short-circuit current detection signal) corresponding to the logic value 1 to the AND circuit 9 in response to the logic value 1.

On the other hand, when the circuit breaker of the substation is tripped by the short circuit current, and as a result, the distribution line L becomes voltageless, the voltage across the diode array Da in the third short circuit detection circuit Xc becomes voltageless, so that the transistor Tr2 The voltage of the resistor R16 (ie, no voltage) is applied to the base terminal of the transistor Tr2, and the transistor Tr2 is turned off. Then, the transistor
Since Tr2 is in an off state, a voltage between the collector and emitter of transistor Tr2, that is, a signal corresponding to a logic value of 1 is applied to the inverter In1.

Therefore, a signal corresponding to the logic value 0 is output from the output terminal of the inverter In1, and the not circuit 13
rectangles the waveform based on the signal corresponding to the logical value 0, and outputs a signal (no-voltage detection signal) corresponding to the logical value 1.

The AND circuit 9 receives a signal (no-voltage detection signal) corresponding to a logic value 1 from the no-voltage detection circuit 51 while a signal corresponding to a logic value 1 from the AND circuit 8 is applied. Based on both signals, the first switch signal corresponding to the logic value 1 is output. Then, the voltage of the resistor R12 is applied to the base terminal of the switching transistor Tr3 based on the first switch signal, so that the switching transistor Tr3 is turned on (conducted).

Then, a voltage is applied to the capacitor C5 and the resistor R10. As a result, a voltage is applied from the capacitor C5 and the resistor R10 to the gate terminal of the thyristor SCR1, making the thyristor SCR1 conductive. Then, due to conduction of thyristor SCR1,
The charge on capacitor C6 is discharged and the short circuit indicator
Outputs the short circuit display drive current to Ha.

This short circuit display drive current causes the short circuit indicator Ha to display a short circuit.

Furthermore, when the thyristor SCR1 becomes conductive, the voltage across the resistor R20 is applied to the switching transistor Tr.
Since the voltage is applied to the base terminal of the switching transistor Tr4, the switching transistor Tr4 is turned on (conducted).
Then, a voltage is applied to the base terminal of the switching transistor Tr5, and the switching transistor Tr5 is turned on. Then, a clear control signal is output from the capacitor C9 and the resistor R21 to the clear terminal 22 of the IC14 of the time limit circuit T according to the time constant of the CR circuit.

When IC14 inputs the clear control signal,
Clear the division of the oscillation number of the oscillation circuit and start re-division of the oscillation number. When a predetermined time has elapsed, the IC 14 applies a time-up signal for a predetermined time from its output terminal via the resistor R53. Then, since the voltage of the resistor R54 is applied to the base terminal of the switching transistor Tr12, the switching transistor Tr12 is turned on (conducted) while the time-up signal is applied, and the differential circuit of the capacitor 22 and the resistor R56 is activated. A voltage is applied to.

As a result, a voltage is applied from the differentiating circuit to the gate terminal of the switching transistor Tr13, so that the switching transistor Tr13
is turned on (conducted) only for the differential time constant time of capacitor C22 and resistor R56. Then, based on the on/off operation of the switching transistor Tr13, the Schmitt trigger circuit SC shapes the signal applied to the Schmitt trigger circuit SC into a waveform, and outputs a display return signal Sig4 to the display Ha.

Display return signal from Schmitt trigger circuit SC
When Sig4 is output, a voltage is applied to the capacitor C8 and resistor R24. As a result, from capacitor C8 and resistor R24 the thyristor SCR2
A voltage is applied to the gate terminal of the thyristor.
Make SCR2 conductive. And thyristor SCR
2 conducts, the charge in the capacitor C6 is discharged, and a return drive current is output to the short circuit indicator Ha.

This return drive current resets the short circuit indicator Ha and returns to the steady display state.

Also, if a short circuit current that can trip the substation circuit breaker flows in the distribution line L to which the second and third current transformers CT2 and CT3 are attached, the short circuit indicator Ha will be activated in the same way as above. A short circuit is displayed and the normal display state is restored after a certain period of time.

Next, when a ground fault occurs in the distribution line L, the phase comparison and discrimination circuit 20 detects the zero-sequence current and zero-sequence voltage flowing in the distribution line L via ZCT2 and ZPD3, and Perform voltage phase comparison.

Then, the phase comparison and discrimination circuit 20 detects that the phase of the zero-sequence current is, for example, 0 to 110, with the phase of the zero-sequence voltage as a reference.
If it is close to the degree advance, it is assumed that the ground fault point is on the right side, and a determination signal corresponding to the logical value 1 is output from the right display output terminal P14 to the AND circuit 21 for a certain period of time.

When the AND circuit 21 receives the determination signal,
A second switch signal corresponding to the logic value 1 is output from the output terminal, and the switching transistor
The voltage of resistor R28 is applied to the base terminal of Tr6 based on the second switch signal. As a result, the switching transistor Tr6 is turned on (conducted), and the capacitor C10 and the resistor R
A voltage is applied to 26. Then, capacitor C
10 and resistor R26 to the gate terminal of the thyristor SCR3.
3 becomes conductive. Then, due to conduction of thyristor SCR3, the charge of capacitor C9 is discharged,
A ground fault display drive current as a ground fault direction display signal is output to the right direction indicator Hb1.

Then, the right direction indicator Hb1 displays the right direction.

On the other hand, when the thyristor SCR3 becomes conductive,
The voltage of resistor R31 is the switching transistor
Since the voltage is applied to the base terminal of Tr7, the switching transistor Tr7 is turned on (conducted).

Then, the potential at the base terminal of the switching transistor Tr8 decreases, and the switching transistor Tr8 turns on. As a result, a clear control signal is output from the capacitor C11 and the resistor R32 to IC1 of the time circuit T by the time constant of the CR circuit.
The voltage is applied to the clear terminal 22 of No. 4.

Then, the time limit circuit T applies the display return signal Sig4 from the Schmitt trigger circuit SC after a certain period of time, similarly to the short circuit display, and applies a voltage to the capacitor C16 and the resistor R44. As a result, from capacitor C16 and resistor R44 the thyristor SCR is
Applying voltage to the gate terminal of 5, the same thyristor
SCR5 becomes conductive. As a result, capacitor C1
5 is discharged, and a return drive current is output to the right direction indicator Hb1.

This return drive current causes the right direction indicator Hb1 to
is reset and returns to the steady display state after a certain period of time.

In addition, when the switching transistor Tr8 turns on, the capacitor C11 and the resistor R32 connect to the gate terminal of the thyristor SCR6.
A gate trigger voltage is applied according to the time constant of the CR circuit, turning on the thyristor SCR6. Then, the charge in the capacitor C17 is discharged, and a return drive current is output to the left direction indicator Hb2.

At this time, if the left direction indicator Hb2 is showing normal display, even if the return drive coil is excited by the return drive current, the magnetic pole part of the stator does not change the magnetic pole, so the disk continues to maintain the normal display state. .

On the other hand, when the left direction indicator Hb2 is in the ground fault direction display state, the magnetic pole part of the stator is at the opposite magnetic pole from that in the normal display state, so the return drive coil is excited by the return drive current. At this time, the magnetic poles of the stator are replaced by the opposite magnetic poles, so that the disk rotates back to normal display.

On the other hand, when the phase of the zero-sequence current is out of phase by, for example, 180 to 290 degrees, the phase comparison/discrimination circuit 11 determines that the ground fault point is on the left side and outputs the left display output terminal P15.
The judgment signal corresponding to the logical value 1 is sent to the AND circuit 2.
3 for a certain period of time.

Then, when the second switch signal corresponding to the logical value 1 is output from the AND circuit 23, the voltage of the resistor R37 is applied to the base terminal of the switching transistor Tr9 based on the second switch signal. As a result, the switching transistor Tr9 is turned on (conducted), and a voltage is applied to the capacitor C13 and the resistor R35. As a result, a voltage is applied from the capacitor C13 and the resistor R35 to the gate terminal of the thyristor SCR4,
The same thyristor SCR4 is made conductive. Then, due to conduction of thyristor SCR4, capacitor C1
2 is discharged and the left direction indicator Hb2
A ground fault display drive current is output as a ground fault direction display signal.

Then, the left direction indicator Hb2 displays the left direction.

On the other hand, when the thyristor SCR4 becomes conductive,
The voltage of resistor R40 is the switching transistor
Since the voltage is applied to the base terminal of Tr10, the switching transistor Tr10 is turned on.

Then, the potential at the base terminal of the switching transistor Tr11 decreases, and the switching transistor Tr11 is turned on. Then, a clear control signal is sent from the capacitor C14 and the resistor R41 to the IC of the time limit circuit T by the time constant of the CR circuit.
14 clear terminal 22.

Then, the timer circuit T applies the display return signal Sig4 from the Schmitt trigger circuit SC after a certain period of time, similarly to the short-circuit display, and applies a voltage to the capacitor C18 and the resistor R46. As a result, from capacitor C18 and resistor R46 the thyristor SCR is
By applying a voltage to the gate terminal of the thyristor,
SCR6 becomes conductive. And thyristor SCR6
As a result of the conduction, the charge in the capacitor C17 is discharged, and a return drive current is output to the left direction indicator Hb2. This return drive current causes the left direction indicator to
Hb2 is reset and returns to a steady display state after a certain period of time.

In addition, when the switching transistor Tr11 turns on, a gate trigger voltage is applied to the gate terminal of the thyristor SCR5 from the capacitor C14 and the resistor R41 according to the time constant of the CR circuit, turning on the thyristor SCR5.
Then, the charge in the capacitor C15 is discharged, and a return drive current is output to the right direction indicator Hb1.

At this time, if the right direction indicator Hb1 is showing normal display, even if the return drive coil is excited by the return drive current, the magnetic pole part of the stator does not change in magnetic pole, so the disk continues to maintain the normal display state. .

On the other hand, when the right side direction indicator Hb1 is in the ground fault direction display state, the magnetic pole part of the stator is the opposite magnetic pole to that in the normal display state, so the return drive coil is excited by the return drive current. At this time, the magnetic poles of the stator are replaced by the opposite magnetic poles, so that the disk rotates back to normal display.

Next, the operation of the power supply voltage check circuit 78 will be explained.

When the battery B maintains a predetermined voltage, the battery check indicator Hc indicates a normal state.

When the battery B becomes lower than the predetermined voltage from this state, the predetermined base voltage is not applied to the base terminal of the transistor Tr15, so the transistor Tr15 enters an off state. Then, a signal corresponding to the logical value 1 is inputted to the inverter In2, and based on that signal, the inverter In2 outputs a signal corresponding to the logical value 0 to the not circuit 25, and the not circuit 25 outputs the signal corresponding to the logical value 0.
A signal corresponding to the logical value 0 is applied to the capacitor C24 and the resistors R65 and R63 based on the signal corresponding to the logic value 0. The AND circuit 26 inputs the signal corresponding to the logic value 1 from the CR differentiation circuit, and based on that signal, applies the signal corresponding to the logic value 1 to the base terminal of the switching transistor Tr16. Tr16 is turned on.

As a result, a display drive current flows through the battery check display Hc through its common terminal 28 and set terminal 29, so that the drive coil (not shown) is energized, and the label attached to the back of the disk is displayed externally. is displayed to indicate that the voltage of battery B has decreased.

Note that when the inverter In2 outputs a signal corresponding to the logical value 0 to the NOT circuit 32, the NOT circuit 3
2 outputs a signal corresponding to the logical value 1 to the not circuit 33 based on the signal corresponding to the logical value 0,
Based on the same signal, the note circuit 33 sends a signal corresponding to the logical value 0 to the capacitor C25, the resistor R67,
Apply to R69. The AND circuit 34 inputs the signal corresponding to the logic value 0 from the CR differentiation circuit,
Based on the signal, a signal corresponding to the logical value 0 is applied to the base terminal of the switching transistor Tr17.
17 is in an off state.

As mentioned above, if the battery check indicator Hc indicates a drop in battery voltage, the battery B
Since it can be confirmed that the battery B has deteriorated, replace the deteriorated battery B with a new battery B.

When battery B is replaced with a new one, the battery B maintains the specified voltage, so the transistor
The voltage divided by the resistor R61 is applied to the base terminal of Tr15, and the transistor is turned on. Then, inverter In2
A signal corresponding to a logical value of 0 is inputted to the inverter In2, and a signal corresponding to a logical value of 1 is applied to the NOT circuit 32 from the inverter In2.

Therefore, the NOT circuit 32 outputs the signal corresponding to the logical value 0 to the NOT circuit 33 based on the signal corresponding to the logical value 1, and the NOT circuit 33 outputs the signal corresponding to the logical value 1 based on the signal. is applied to capacitor C25 and resistors R67 and R69. The AND circuit 34 inputs the signal corresponding to the logic value 1 from the CR differentiation circuit, and based on the input signal, the signal corresponding to the logic value 1 is applied to the switching transistor.
Since the voltage is applied to the base terminal of Tr17, the switching transistor Tr17 is turned on.

As a result, since the reset drive current flows through the common terminal 28 and the reset terminal 12, the battery check indicator Hc
When Hc is excited, a return drive coil (not shown) is energized, and a mark attached to the surface of the disk is displayed to the outside, indicating that battery B maintains a predetermined voltage value.

Note that when the inverter In2 outputs a signal corresponding to the logical value 1 to the not circuit 25, the not circuit 25 outputs the signal corresponding to the logical value 0 to the capacitor C24, the resistor R65, based on the signal corresponding to the logical value 1. Apply to R63. The AND circuit 26 inputs the signal corresponding to the logic value 0 from the CR differentiation circuit, and based on that signal, applies the signal corresponding to the logic value 0 to the base terminal of the switching transistor Tr16. Tr16 is in an off state.

In this way, in this embodiment, the forward voltage across the diode array Da detected by the current transformer CT is made constant, and the internal power supply type is used to charge the battery B, so that a separate power supply is not required.

In addition, the third short-circuit detection circuit Xc detects no voltage based on the presence or absence of forward voltage across the diode array Da, so there is no need to detect the potential between PT or ground, which may pose a risk to insulation performance. There is no.

Furthermore, in the short-circuit detection circuit Xc, the photocoupler PC inputs analog signals based on the short-circuit current, and the same photocoupler PC outputs digital signals. The resistance value of the resistor R1 can be reduced, thereby reducing the heat generated by the resistor R1.

In addition, in the third short circuit detection circuit Xc, a diode array is connected in series to the digital output and the short circuit detection circuit by the photocoupler PC.
Da can be isolated, thereby enabling a configuration in which the short circuit detection circuit Xc, power supply circuit Z, and no-voltage detection circuit 51 are connected to one current transformer CT. Therefore, unlike in the past, the power supply circuit Z
The distribution line L of one of the three phases is used just to connect the
It is no longer necessary to secure a current transformer CT installed in each phase, and each current transformer installed in each distribution line L of each phase
Short circuits can be detected for all three-phase distribution lines L via CT1, CT2, CT3 and the corresponding short circuit detection circuits Xa, Xb, and Xc.

Further, in the short circuit detection circuits Xa, Xb, and Xc, the short circuit indicator Ha is driven to display by discharging the capacitor C6, so that almost no current for driving needs to be consumed.

In addition, in this embodiment, the short circuit indicator Ha and the direction indicators Hb1 and Hb2 are constructed by electrically connecting magnetic reversal indicators in parallel, so the circuit impedance is reduced and the capacitor used as the drive power source is C6, C9, C12, C15, C1
7 improves the discharge efficiency and ensures reliable display driving.

Also, in this embodiment, the time limit circuit T connects the time-up signal from the IC 14 to the switching transistor.
Since it is amplified by Tr13 and employs a Schmitt trigger circuit SC, operational reliability can be improved, and the switching circuit 57,
68, 73 multiple thyristors SCR2, SCR5,
Can drive SCR6.

Furthermore, since the control circuit uses an IC as described above, there is an advantage that the current consumption of the control circuit is small.

Further, in this embodiment, when the battery B does not hold a predetermined voltage, the power supply voltage check circuit 78
operates and displays the battery check indicator Hc, making it easy to check the voltage of battery B.

Furthermore, in this embodiment, a right direction indicator Hb1 and a left direction indicator Hb2, which constitute the ground fault direction indicator, are
If a further ground fault occurs while the ground fault direction is already being displayed, the old ground fault fault display can be restored to its original normal display state and the latest ground fault fault display can be displayed.

Next, a second embodiment will be explained with reference to FIGS. 7 and 8.

This embodiment differs greatly from the first embodiment in that the time limit circuit T is provided with a fault current detection and holding circuit 81, an AND circuit 82 as a gate circuit, an oscillation holding circuit 83, and a holding release circuit 84.

Each of the above circuits will be explained in detail below. Note that the same reference numerals are given to the same or corresponding configurations as those of the first embodiment, and the explanation thereof will be omitted.

As shown in FIG. 7, the fault current detection signal holding circuit 81 outputs a signal corresponding to a logical value of 0 from its output terminal when the distribution line L is steady, and also outputs a clear control signal when a fault current is detected. Sig
If you enter one of 1, Sig2, or Sig3,
A signal corresponding to the logical value 1 is continuously output from the output side to the next stage.

Further, while this fault current detection signal holding circuit 81 is continuously outputting a signal corresponding to a logical value 1 as described above, when a signal corresponding to a logical value 1 is inputted from a holding release circuit 84 (to be described later), A signal corresponding to a logical value of 0 is output from its output side.

Specifically, this fault current detection signal holding circuit 81 is constructed as shown in FIG.

That is, clear control signals Sig1, Sig2, Sig
One input terminal of an OR circuit 86 is connected to the output terminal of the OR circuit 85 which inputs 3, and the output terminal of the OR circuit 86 is connected to one input terminal a of an AND circuit 87. Furthermore, the AND circuit 8
The output terminal of 7 is connected to the other input terminal of the OR circuit 86, and is also connected to one input terminal a of the AND circuit 82. Further, the other input terminal of the AND circuit 87 is connected to an output terminal of an AND circuit 93 of the hold/release circuit 84, which will be described later, via an inverter In10.

The OR circuit 86, the AND circuit 87, and the inverter In10 form a fault current detection signal holding circuit 81.

Note that the other input terminal b of the AND circuit 82
is connected to the output terminal of the inverter In1 of the no-voltage detection section.

Next, as shown in FIG. 7, when the AND circuit 82 is outputting a signal corresponding to a logical value 0, the oscillation holding circuit 83 outputs a signal corresponding to a logical value 1 based on the signal corresponding to a logical value 0. Also, when the AND circuit 82 outputs a signal corresponding to the logical value 0→1, the signal corresponding to the logical value 1→0 is output to the IC based on that signal.
The signal is output to the clear terminal 22 of the IC 14 to cause the IC 14 to start oscillating.

Further, while this oscillation holding circuit 83 is outputting a signal corresponding to a logical value 0 as described above, a holding release circuit 84 (to be described later) outputs a signal corresponding to a logical value 1.

Specifically, the oscillation holding circuit 83 is constructed as shown in FIG.

That is, the output terminal of the AND circuit 82 is connected to one input terminal of an OR circuit 88, and the output terminal of the OR circuit 88 is connected to one input terminal of an AND circuit 89. The other input terminal of the AND circuit 89 is connected to the output terminal of an AND circuit 93 of the holding release circuit 84, which will be described later, via an inverter In11. Further, the output terminal of the AND circuit 89 is connected to the clear terminal 22 of the IC 14 via a NOT circuit 90.

An oscillation holding circuit 83 is constituted by the OR circuit 88, the AND circuit 89, the NOT circuit 90, and the inverter In11.

Further, one input terminal of a NAND circuit 91 is connected to the output terminal of the IC14, and the other input terminal of the NAND circuit 91 is connected to a series circuit of resistors R100, R101 and an inverter In12, and the positive terminal of the resistor R101 is connected to the output terminal of the IC14. A capacitor C100 is connected between the ground line E and the ground line E. Further, the output terminal of the NAND circuit 91 is connected to the gate terminals of thyristors SCR1, SCR5, and SCR6 via an inverter In13 and diodes D8, D23, and D28, respectively.

Said IC14, resistors R50, R51, capacitor C20, NAND circuit 91, resistors R100, R1
01, capacitor C100, inverter In12,
In13 constitutes a time limit circuit T.

This IC14 receives a logic value of 0 from the oscillation holding circuit 83.
When a signal corresponding to is input, the oscillation circuit 74 starts oscillating. And IC1
When a signal corresponding to a logical value 1 is output after a predetermined time from 4, one pulse signal corresponding to a logical value 0 is output from the NAND circuit 91, and thereby, the inverter In13 corresponds to a logical value 1 as a display return signal Sig4. A signal is output to apply a gate trigger voltage sufficient to turn on the thyristors to the gate terminals of the thyristors SCR1, SCR5, and SCR6.

Next, when the IC 14 continues to stop oscillation, the holding release circuit 84 sends a signal corresponding to the logic value 0 from its output side to the fault current detection holding circuit 84.
1 and is output to the oscillation holding circuit 83. Further, when a signal corresponding to a logical value 1 is inputted from the inverter In13, a signal corresponding to a logical value 1 is outputted from its output side.

Specifically, this hold/release circuit 84 is constructed as shown in FIG. That is, inverter In1
3 is connected to the input terminal of the AND circuit 92, and the output terminal of the AND circuit 92 is connected to the resistor R10.
2, AND circuit 93 via the series circuit of R103
is connected to the output terminal of Also, the resistor R1
A resistor R104 and a diode D1 are connected to both terminals of 02.
00 series circuits are connected in parallel, resistor R102
The negative terminal of is connected to the ground wire E via the capacitor C101.

The AND circuits 92, 93, resistors R102, R
103, R104, a diode D100, and a capacitor C101 constitute a holding release circuit 84.

In addition, a resistor R is connected between the emitter of the transistor Tr14 of the power supply circuit Z and the negative terminal of the full-wave rectifier 6.
A series circuit of a diode D101 and a capacitor C102 is connected through the capacitor C105.
By connecting the positive terminal of C102 to each circuit of the fault current detection signal holding circuit 81, the capacitor C102 is connected to the fault current detection signal holding circuit 81.
It is used as a power source. And this capacitor C1
02, even if the distribution line L is in a no-voltage state, voltage is applied to the fault current detection signal holding circuit 81.

In this embodiment, a capacitor C103 is used in place of the battery B of the first embodiment.

Now, in the short circuit/ground fault direction detection and display device configured as described above, when the distribution line L is in a steady state, a signal corresponding to the logic value 1 is output from the inverter In1 of the no-voltage detection section. A signal corresponding to the logic value 1 is input to the input terminal b of the circuit 82. That is, the AND circuit 82 receives a signal corresponding to the logical value 1 at its input terminal b, and inputs a signal corresponding to the logical value 0 at one input terminal a of the AND circuit 82, so the AND circuit 82 receives the logical value 1. A signal corresponding to 0 is output to the next stage.

Since the oscillation holding circuit 83 receives a signal corresponding to the logical value 0, it outputs a signal corresponding to the logical value 1 from its output side to the clear terminal 22 of the IC 14, and as a result, the IC 14 continues to stop oscillating. do.

Next, for example, a short circuit failure that can trip a substation breaker occurs in the distribution line L, and as a result, the short circuit indicator Ha is displayed as in the first embodiment, and
Correspondingly, from the voltage amplification circuit 56 to the OR circuit 8
When the fault current detection signal holding circuit 81 receives the clearing control signal Sig1 of 5, the signal corresponding to the logic value 1 is continuously output from the output side to the input terminal a of the AND circuit 82. When the substation circuit breaker trips due to the short circuit fault and the distribution line L becomes a no-voltage embodiment, the inverter In1 of the no-voltage detection section
A signal corresponding to the logic value 0 is outputted from the AND circuit 82, and the signal corresponding to the logic value 0 is input to the input terminal b of the AND circuit 82.

That is, since the signal corresponding to the logical value 1 is input to the input terminal b of the AND circuit 82, the AND circuit 82 outputs the signal corresponding to the logical value 0 to the oscillation holding circuit 83. Furthermore, if the retransmission of power from the substation to the distribution line L is successful after this, a signal corresponding to the logic value 1 is output from the inverter In1 of the no-voltage detection section, and as a result, the signal corresponding to the logic value 1 is output to the input terminal b of the AND circuit 82. Since the signal corresponding to the logical value 1 is inputted, that is, the signal corresponding to the logical value 1 is inputted to the AND circuit 82, the AND circuit 82 outputs the signal corresponding to the logical value 1 to the oscillation holding circuit 83. do.

As a result, the oscillation holding circuit 83 is connected to the AND circuit 82.
Since a signal corresponding to the logical value 0 → 1 is input from , the oscillation holding circuit 83 outputs a signal corresponding to the logical value 1 → 0 to the clear terminal 22 of the IC 14 based on the signal, causing the oscillation circuit 74 to oscillate. Let it start.

After a predetermined period of time has elapsed, the IC 14 outputs a signal corresponding to a logic value of 1 from its output terminal. As a result, 1 corresponding to the logical value 0 is output from the NAND circuit 91.
As a result, the inverter In13 outputs a signal corresponding to the logic value 1 as the display return signal Sig4, and the thyristor
Apply a gate trigger voltage sufficient to turn on thyristor SCR1 to the gate terminal of SCR1,
Thereafter, the short circuit indicator Ha is returned to display in the same manner as in the first embodiment.

At the same time, when the hold release circuit 84 receives a signal corresponding to the logical value 1 from the inverter In13,
Based on this signal, the holding release circuit 84 outputs a signal corresponding to the logical value 1 from its output side to the fault current detection signal holding circuit 81 and the oscillation holding circuit 83. Then, the fault current detection signal holding circuit 81 outputs a signal corresponding to a logical value 0 from its output side based on that signal, while the oscillation holding circuit 83 outputs a signal corresponding to a logical value 1 based on that signal. Output. As a result, the IC 14 stops the oscillation of the oscillation circuit 74. That is, the fault current detection holding circuit 81 and the oscillation holding circuit 83 return to their original states.

Note that even if a ground fault that can trip the substation circuit breaker occurs in the distribution line L, each circuit operates in the same manner as in the case of the short circuit fault.

In addition, if the distribution line L goes into a no-voltage state due to the substation breaker tripping for reasons other than short circuits and fault currents due to ground faults, and if power is successfully retransmitted to the distribution line L after this, input terminal b of the AND circuit 82 A signal corresponding to the logical value 1→0→1 is input by the no-voltage detection section. However, the fault current detection signal holding circuit 81
Since the clear control signals Sig1, Sig2, and Sig3 are not input to the fault current detection signal holding circuit 81, the output side of the fault current detection signal holding circuit 81 outputs a signal corresponding to the logic value 0 when the distribution line L is in a steady state. Since the IC 14 outputs a signal corresponding to the value 0, and thereby the oscillation holding circuit 83 outputs a signal corresponding to the logical value 1, the IC 14 remains in a state in which oscillation is stopped.

In this way, in this second embodiment, the signal output from the fault current and the AND condition of no voltage on the distribution line L, and the AND condition when the substation retransmits power.
IC14 is operated by a timer, and after a certain period of time, IC1
4 stops the oscillation of the oscillation circuit 74.

Other effects are similar to those of the first embodiment.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be modified as desired without departing from the spirit of the present invention.

Effects of the Invention As described above, in the short-circuit detection circuit of the present invention, a photocoupler is used to input an analog signal based on a short-circuit current, and the photocoupler is used to output a digital signal. Depending on the performance, the resistance value of the resistor in the short-circuit detection circuit can be reduced, and thereby the heat generation of the resistor can be reduced.

In addition, in the short circuit detection circuit, the photocoupler allows the elements connected in series to the digital output and the short circuit detection circuit to be isolated, thereby making it possible to isolate the power supply circuit and the short circuit detection circuit for the same current detector. It is possible to connect together,
Unlike the conventional method, which could only detect short circuits in two of the three phases, this system has the excellent effect of being able to detect short circuits in all three phase distribution lines while charging the power supply circuit using the charging current from the distribution lines. play.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a short-circuit/ground fault direction detection/display device according to an embodiment of the present invention, and FIG. 2 is an electrical block circuit diagram of the short-circuit/ground fault direction detection/display device, where a indicates a circuit other than a time-limited circuit. electrical block circuit diagram,
b is an electrical block circuit diagram of a time-limited circuit, FIG. 3 is an electrical circuit diagram of a short-circuit/ground fault direction detection display device, FIG. 4 is a schematic diagram of a short-circuit indicator, and FIG. 5 is an explanatory diagram for showing the same function. , FIG. 6 is an electric circuit diagram of the short circuit indicator, FIG. 7 is an electric block circuit diagram of the main part of the second embodiment, and FIG. 8 is an electric circuit diagram embodying the block of FIG. 7. DESCRIPTION OF SYMBOLS 1...Short circuit ground fault direction detection display device, 2...Zero-sequence current transformer, 3...Zero-sequence voltage detector, 6...Full-wave rectifier, 8...AND circuit (first waveform manipulation circuit), 9...AND circuit (short circuit gate circuit), 1
3...Knot circuit, 14...IC, 20...Phase comparison/discrimination circuit, 21, 23...AND circuit (ground fault detection gate circuit), 25...Knot circuit, 26
...AND circuit, 32,33...NOT circuit, 3
4...AND circuit, 51...No voltage detection circuit, 5
2...Second waveform manipulation circuit, 55...First switching circuit, 65, 70...Second switching circuit, Xa...First short circuit detection circuit, Xb...Second short circuit detection circuit, Xc...Third short circuit detection circuit,
Z...power supply circuit, T...time limit circuit, Ha...short circuit indicator, Hb1...right direction indicator, Hb2...left direction indicator, Hc...battery check indicator,
CT1...first current transformer, CT2...second current transformer, CT3...third current transformer, L...
distribution line.

Claims (1)

[Claims] 1. A short-circuit detection circuit that detects a short-circuit current flowing through a distribution line via a current detector installed in the distribution line and outputs a short-circuit current detection signal, and when a circuit breaker in a substation trips. a no-voltage detection circuit that detects a no-voltage state of the distribution line via the current detector and outputs a no-voltage detection signal; a short-circuit current detection signal from the short-circuit detection circuit;
a short-circuit detection gate circuit that outputs an operation signal when a no-voltage detection signal from a no-voltage detection circuit is input together; and a short-circuit indicator that operates to indicate a short circuit based on the operation signal output from the short-circuit detection gate circuit. , a short circuit detection display device comprising a power supply circuit that is charged by a charging current output from a current detector provided on a power distribution line and supplies a driving current to each of the circuits, wherein the short circuit detection circuit is arranged in a power supply circuit. Equipped with a photocoupler that converts the analog signal output by the current detector into a digital signal when a short-circuit current flows through the wire,
The circuit is configured to output a digitized short-circuit current detection signal based on the analog signal, and connects the short-circuit detection circuit to each current detector provided in each phase distribution line, and short-circuits the power supply circuit. A short circuit detection display device characterized in that a detection circuit is connected to a connected current detector.