JPS5850499B2 - Electrical device for producing a given voltage vs. time response - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improved electrical device for providing a predetermined voltage vs. time response, and in particular to an overcurrent relay having inverse timing characteristics with respect to the magnitude of the human input signal.

Conventional static delay relay circuits typically employ curve shapers to provide relay characteristics similar to conventionally widely used electromechanical devices.

Curve shapers are disclosed in U.S. Pat. Nos. 3,496,417 and 3,544,846.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved electrical device for providing a predetermined current vs. time response in order to overcome the drawbacks of the prior art.

The present invention comprises an input means for receiving a DC voltage, and a delay detection circuit connected to the input means and supplying an output quantity of electricity with a delay time dependent on the magnitude of the DC voltage, in order to perform a predetermined voltage versus time response. This delay detection circuit is equipped with
an RC delay circuit, a pulse generation circuit, and a counting circuit having at least one branch connected between an input terminal and an output terminal, the RC delay circuit having the input terminal supplied from the input means; The pulse generation circuit generates a pulse when the output of the RC delay circuit reaches a predetermined value. This pulse causes the counting circuit to count up,
Further, the RC delay circuit is reset to respond to the DC voltage again, and the counting circuit is configured to supply the output quantity of electricity when receiving a predetermined number of pulses from the pulse generating circuit. It is an electrical device for making a voltage versus time response.

The invention will become more easily apparent from the following illustrative description with reference to the accompanying drawings.

FIG. 1 shows an example of a electrical quantity response device, ie, a protective relay, in which the electrical device of the invention is incorporated and combined with an electrical circuit to be protected.

This electrical circuit can be of any type that has the conditions to which the electrical quantity responsive device is intended to respond.

In the present invention, the electrical circuit is assumed to be a three-phase alternating circuit operating at a frequency of 60 Hertz and represented by line conductors Ll, L2 and L3.

These line conductors transmit alternating current from suitable wires through a circuit breaker 4 having a trip coil 6 to the load.

The circuit breaker 4 has a plurality of separable line contacts 8, 10.
It further has $- and 12.

These contacts close when the circuit breaker 4 is closed and open when the circuit breaker 4 is tripped.

When the circuit breaker 4 is closed, the trip coil 6
When the circuit breaker 4 is energized, the circuit breaker 4 performs a tripping operation, that is, an opening operation.

Although the invention is illustrated for polyphase circuits, it should be clearly understood that it is equally applicable to single-phase circuits.

The invention can be used to monitor the total current of a single-phase circuit or a multi-phase circuit, depending on the circuit that combines the outputs of the sensing windings of current transformers.

In the present invention, a current relay is responsive to the magnitude of line current flowing through line conductors L1, L2, and L3 and is responsive to the magnitude of line current flowing through line conductors L1, L2, and L3. Responsive to the maximum current value of L2 and L3.

When the magnitude of this current exceeds a predetermined value for a time interval dependent thereon, the relay energizes the trip coil 6 virtually instantaneously or after a predetermined delay time depending on the magnitude of the current. Trip circuit breaker 4.

As shown in FIG. 2, input circuit 100 comprises a plurality of virtually identical current transformers CTI, CT2 and CTa.

The input windings or primary windings 102 of these current transformers are:
Line conductors L1, L2, respectively. Individually energized by the line current of L3.

Each current transformer has a first output winding 104, called the power winding.
and a second output winding 106 called the information winding.

Both output windings are connected with the same magnetic flux, but the number of turns N1 in each power winding is less than the number N2 of turns in each information winding.

For simplicity of explanation, only the operation of the current transformer CTI and its associated circuitry will be described in detail.

All three current transformers and their associated circuits operate in the same manner, each producing a first quantity of electricity, i.e. a first output current o
1 and a second quantity of electricity, that is, a second output current ■o2.

These output currents are proportional to the line current energizing the respective current transformer.

Current transformer CT1 is energized in response to the line current flowing through line conductor L1 in its human powered winding 102.

The power winding 104 and the information winding 106 are connected to a full wave rectifier bridge RE 108. having output terminals 112-114, 116-118, respectively. Connected to the input terminal of REl 10.

Output terminals 112 and 116 are connected to a common busbar, shown as ground.

Output terminals 114 and 118 are connected to a first input terminal and a second input terminal of control circuit 120, respectively.

The control circuit 120 includes a voltage-operated element shown as a Zener diode Z122, a first switching element T124 shown as a PNP transistor, a plurality of diodes D126, D121- and D130, and a second switching element shown as a thyristor. 5CR13
6, capacitors C137, C166 and C168, and multiple resistors R138, R140, R142°R14
4 and R146.

Control circuit 120 includes power winding 104 and information winding 10
6. Perform the sequential operations.

Hereinafter, the term "thyristor" will be used to mean any switching element having a first terminal or anode, a second terminal or cathode and a third terminal or gate.

Once conducting, the thyristor will not become non-conducting unless the current flowing into the anode decreases and remains less than a predetermined magnitude for at least a minimum period of time (this is called the minimum shaft-off time).

Following each zero crossing of the line current flowing through the line conductor L1, the input ampere turns are balanced by the output type 1Io1 flowing through the power winding 104.

During this time, the information winding 106 remains open and is inoperable because the thyristor 5CR136 is in an immobile conducting state acting as an open switch.

The output current Io1 is rectified by the full-wave rectifier bridge RE108 and used to charge the power supply circuit 148.

A portion of the output current o1 is diverted between output terminals 112 and 114 through a diode D126 and an energy storage element or capacitor C150, providing a positive (relative to ground) voltage V8+ at output terminal 152.

A part of the music of the rectified output current ■o1 is connected to the output terminal 11.
2 and 114 through the diode D128 and the energy storage element or capacitor C162, thereby providing a virtually ripple-free regulated voltage between the output terminal 156 and ground, i.e., the reference voltage having the reference voltage 8. Power is supplied to the supply circuit 154.

This reference voltage supply circuit 154 is used to supply power for the small current drain.

A reference voltage supply circuit 154 is connected in parallel with a capacitor C150, and is connected in series with R158 and a rheostat R160.
Consists of.

Adjusting resistor R160 connects capacitor 1 via resistor R158.
62.

A movable arm of rheostat R160 is connected to output terminal 156.

Filter capacitor C164 is connected between the movable arm of Calo-reducing resistor R160 and ground.

The voltage between the output terminal 114 and the ground is the breakover voltage VZt□2 of the temperature compensation Zener diode Z122.
When lower than , the small output type 1Io1 is the transistor T
124 and exits through resistor R140.

The rectified output current Io is connected to capacitors C150 and C1.
62, the voltage at each of its terminals rises by 1 approaching a magnitude equal to VZI□2, which is the regulated output voltage ■8.

Apart from preventing discharge of capacitors cisoi- and C162, diodes D126 and D128 provide temperature compensation of the regulated voltage as they seek to balance the base-emitter junction temperature effects of transistor T124.

The terminal voltage of capacitors C150 and C162 is virtually ■2
When 12□ is reached, Zener diode z122 booms over and conducts current through resistor R138.

This lowers the base voltage of transistor T124, and the base drive current flows, causing transistor T124 to conduct, causing current to flow through its emitter-collector circuit, diode D130, and resistor R142.
Energize the gate of thyristor 5CR136.

In FIG. 2, resistor R144 and capacitors C166 and C168 are connected to thyristor 5C by a noise signal that may occur at the gate or by a temperature-related leakage current at the anode.
Connected to prevent R136 from being energized.

When the gate is energized, thyristor 5CR136 conducts and thyristor 5C is connected between output terminals 116 and 118.
The current path of the rectified output current Io2 through the anode and cathode of R136, resistor R146 and the common bus is completed.

This causes Io2. across resistor R146. Generates a voltage equal to R146.

Since power winding 104 and information winding 106 are coupled with the same magnetic flux, the relative magnitudes of the voltages in power winding 104 and information winding 106 must be the same as the turns ratio N1:N2.

After thyristor 5CR136 conducts, the voltage level at output terminals 116 and 118 becomes virtually equal to the voltage developed across resistor R146, and output terminal 1
The voltage level at 12 and 114 is approximately ■21□2
+The voltage between the emitter and base of transistor T124 decreases by approximately IO2tR146, N1/N21.

The values of the number of turns N1 and N2, the value of the resistor R146, and the maximum expected value of Io2 are IO2*R146,N1/N2 for all expected values of the line current passing through the line conductor L1.
must be chosen such that the magnitude never exceeds 2.22+the emitter-base voltage of transistor T124.

A suitable design value (but not critical) for the illustrated electrical quantity response device is a value for which the magnitude of Io2 corresponds to the maximum line current value of line conductors L1, L2 and L3 (this is 40% of the minimum pickup current). (equal to twice the size).

The minimum pickup current is determined by the pickup comparison circuit 402.
is defined as the lowest line current that produces the lowest magnitude pickup voltage that activates the

In order to limit the magnitude of Io2 at line currents greater than 40 times the pick-up value, a limiter circuit, which will be explained in more detail below, is provided.

When thyristor 5CR136 is energized, resistor R146
The voltage across D130 will be higher than the voltage across output terminals 112, 114, thus reverse biasing diode D130.

The voltage between the output terminals 112° and 114 becomes lower than the voltage V212□, and no current flows through the Zener diode z122.

The voltage between output terminals 112 and 114 is connected to capacitor C150.
, C162, but the diode D
126 and D128 are reverse biased so no discharge current flows.

Thus, when thyristor 5CR136 conducts, power winding 104 is effectively opened.

Once the gate of thyristor 5CR136 loses control of this thyristor, the rectified output current Io2 begins to flow between its anode and cand, and thyristor 5CR136 is attached at 1 when the line current in line conductor L1 reaches the next zero crossing point. The current situation will continue.

When the thyristor 5CR136 is deenergized, the information winding 106 is opened.

The primary ampere-turns are then balanced by power winding 104 only, and the magnitude of the voltage at output terminals 112 and 114 is equal to the magnitude determined by the ampere-turn balance principle of input winding 102 and power winding 104.
to jump.

Power winding 104 becomes effective in recharging capacitors C150 and C162 as described above.

When the thyristor 5CR136 is energized, the rectified output current Io2 across the resistor R146 provides the appropriate information voltage, regardless of whether the signal is processed as an effective value, a peak value, or an average value. provide.

The voltage across resistors R170 and R172 is applied to each line conductor L2. This becomes an information voltage proportional to the line current of L3.

The power supply circuit 148 is pre-charged for an initial portion of each half-cycle of line current and then supplies the voltage for the remaining portion of each half-cycle.

During each half cycle of line current in line conductor L1, power winding 1
The length of time that 04 and information winding 106 are each valid is determined by setting the terminal voltage of capacitors C150 and C162 to VZ.
It depends on the time required to recharge with a voltage value residue equal to 122.

If the information voltage is to be processed as an effective value or an average value, the accuracy of this processed information voltage is equal to the capacitor C150.
, C162, and the circuit components should be selected to recharge the power supply circuit 148 in an appropriately short period of time given the allowable load on the AC circuit being monitored. .

In order to detect the peak signal, it is only necessary to limit the charging time to less than 90° of the sinusoidal line current.

The magnitude of resistors R146, R170 and R172 should be small enough to match the desired sensitivity to reduce loading.

A suitable value may be 50 ohms.

The multiphase overcurrent relay of FIG. 2 responds to the largest line current among the line currents flowing through line conductors L1, L2, and L3.

The highest voltage signal supply circuit 174 includes resistors R146 and R17.
providing a first highest voltage signal responsive only to the highest of the three voltages developed across diode DI75. DI76 Fu・yobi D17
Equipped with 7.

Each of these diodes is connected to a resistor R146,
Output conductor 17 common to non-grounded ends of R170 and R172
8 (this is connected to the peak voltage averaging circuit 200)
connected between.

Resistance 146. The highest voltage across R170t or R172 determines the magnitude of the voltage on output conductor 178.

3 solar diodes D175. D176 Muyobi D177
Two of the diodes are reverse biased.

The highest voltage signal supply circuit 174 supplies a second highest voltage signal similar to the first highest voltage signal and connects the diode D18.
1. It is equipped with a D182 button and a D183 button.

Each of these diodes is connected to a respective resistor R146.
, R170, R172 and the common output conductor 1
84 (which is connected to limiter circuit 186).

The second highest voltage signal is provided to limiter circuit 186.

A limiter circuit 186 connects output conductor 184 to ground in parallel with resistors R146, R170 and R172.

When the second highest voltage has a magnitude greater than 40 times the pick-up current, voltage regulating element Z188, illustrated as a Zenata" diode, breaks over.

When Zener diode Z188 breaks over,
The thyristor 5CR190 whose cathode is grounded is conductive.

Limiter circuit 186 typically includes resistors R146 and R170.
By effectively blocking all of the current flowing through R172 and R172, the entire input circuit is disabled.

A resistor R192 is provided to limit the current flowing through the gate of thyristor 5CR190 when Zener diode 2188 is conductive.

Resistor R194 and capacitor 196 are connected to thyristor 5
The connection is made to prevent CR 190 from being energized by noise signals that may be applied to its gate.

The highest voltage across output terminals 112, 114 is lower than VZ 122 plus the emitter-base voltage of transistor T124 (one or more information windings 106 energize load resistors R146, R170, or R172, respectively). current transformer CT1. Cr
Another form of current limiting is provided by designing Cr2 and Cr2 to saturate at a predetermined level of line current.

As shown in FIG. 3, output conductor 178 provides a first highest voltage signal to peak voltage averaging circuit 200. As shown in FIG.

The peak voltage averaging circuit 200 may be of any type, but is a filter consisting of a filter capacitor C201 and a resistor R204 connected in parallel as shown.

The peak voltage averaging circuit 200 energizes the output conductor 202 with a DC voltage whose magnitude is proportional to the average of the peak values of the first highest voltage.

Output conductor 202 of peak voltage averaging circuit 200 is connected to delay detection circuit 400 and instantaneous trip detection circuit 500.

The delay detection circuit 400 includes a pickup comparison circuit 402, a digital counting circuit 406, a reset RC delay circuit 410, an interface 412, and a monostable multivibrator 414, as shown in more detail in FIG.

After a predetermined time TD when the magnitude of the DC voltage from peak voltage averaging circuit 200 exceeds its lowest predetermined pickup value, counting circuit 406 directly or A control signal is provided through instantaneous trip detection circuit 500 to energize trip circuit 600 .

The length of the delay time TD is inversely proportional to the magnitude of the DC pickup voltage, except that the shortest delay time is provided by the time it takes for the monostable multivibrator 414 to change its state. do.

As will be explained in detail below, the delay detection circuit 40
0 can provide an output voltage according to any desired inverse timed response curve depending on the values of R and C used for the RC delay circuit 410 and can set the counting circuit 406.

Pickup comparison circuit 402 detects delay detection circuit 40 whenever the magnitude of the DC pickup voltage from peak voltage averaging circuit 200 is less than a predetermined pickup value.
0 is prohibited from operating, that is, the delay detection circuit 4
00, but when the pickup voltage exceeds the minimum value, the delay detection circuit 400 is activated.

Pickup comparison circuit 402 includes a comparator 408.

Comparator 408 has a negative input terminal connected to and energized by peak voltage averaging circuit 200, and a positive input terminal connected to output terminal 156 of reference voltage supply circuit 154 (FIG. 2). have

The reference voltage (2) determines the minimum pickup voltage and can be adjusted with the movable arm of rheostat R160 (FIG. 2).

The output voltage of the peak voltage averaging circuit 200 is the reference voltage ■8
, comparator 408 draws no current from output terminal 152 and output conductor 409 is effectively at a positive voltage.
+ is maintained.

When the pickup voltage exceeds the reference voltage ■8, comparator 4
08 effectively grounds the output conductor 409 and connects the counter 4
44, 446 and 447 are placed in a state for counting pulses from monostable multivibrator 414.

A suitable comparator 408 is a monolithic four unit comparator integrated circuit MC33 commercially available from Motorola.
This is the first unit of 02P.

The MC3302P includes four identical comparator units arranged in a 14-lead, 2-in-line plastic package.

The second, third and fourth units of the MC3302P are advantageously utilized in the delay detection circuit 400 and the instantaneous trip detection circuit 500.

The inverse timed response curve is R with a resistor and a capacitor.
C delay circuit 410, interface 412, and monostable multivibrator or one-shot element 414.
It is formatted by 1.

The capacitor is deenergized each time the output voltage at output terminal 436 of RC delay circuit 410 exceeds reference voltage VR.

Transistor T414. T416゜T411- and T4
20 are connected in parallel with their corresponding capacitors, and their bases are connected to the output side of the monostable multivibrator 414.

Each time the monostable multivibrator 414 generates a pulse, the transistor conducts and discharges the capacitor, thus causing the RC delay circuit 410 to output a pulse to the counters 444, 446.
A periodic operation is performed to supply pulses to and 447.

The pulse generation circuit 404, the delay time TD1 provided by the RC delay circuit 410 (which is a function of the magnitude of the line current), and the fixed delay time TD2 of the monostable multivibrator 414 provide two timing characteristics. provided.

RC delay circuit 410 includes multiple parallel branches.

Each branch contains a capacitor, and each capacitor is charged at a different time (if you draw this on semi-log paper,
The time/current relationship is curves 426, 428, and 43 in Figure 4.
0 and 432).

The curve 424 is the line conductor Ll. RC delay circuit 41 when suddenly energized with a DC voltage signal proportional to the peak value of the largest line current among the line currents flowing through L2 and L3.
0 shows the inverse timed current relationship obtained by 0.

It will be appreciated that this curve 424 is the sum of curves 426-432.

Therefore, the time it takes for the equivalent voltage response value of the RC delay circuit 410 to rise from zero to a predetermined magnitude is inversely proportional to the peak of the maximum line current.

Although four branch paths are shown in FIG. 3, any number of branch paths may be used.

Each path of RC delay circuit 4100 includes two resistors connected in series between input terminal 434 and output terminal 4360, and a capacitor connected in parallel between the connection point of these two resistors and ground.

FIG. 5 is shown for analysis of the RC delay circuit 410.

Assume that all capacitors are initially uncharged and the voltage VIN between input terminal 434 and ground suddenly rises above the minimum pickup value.

The branch capacitors are charged individually at different rates.

During this time, the voltage VIN is determined by the magnitude of the fault current (assumed to be constant in magnitude during a given fault condition) and causes a charge to flow into the IRcA capacitor.

Voltage ■. UT appears at the output terminal 436 of the RC delay circuit 410.

The second component charging current IRCB flows from the output terminal 438 of the operational amplifier 413 through the Zener diode Z440 and the diode D442 into the RC delay circuit 410 for closed loop operation of the circuit including the operational amplifier 413.

When the capacitor in RC delay circuit 410 is charged at its critical charge value, the charging current IRCB becomes zero.

However, since the voltage at input terminal 434 is naturally higher, current continues to flow to charge the capacitor, and the voltage at output terminal 436 rises enough to cause the operational amplifier to lower the voltage at its output terminal 438. .

Let the voltage at the input terminal 434 be □, and the voltage at the output terminal 4
36 days later ■.

UT, and the voltage at the non-grounded end of the capacitor is ■
.

and set the resistance value between the capacitor and input terminal 434 to R7.
, the resistance value of the resistor between the capacitor and the output terminal 436 is R2, the magnitude of the current flowing into the capacitor from the output terminal 436 is ■RCB, and the magnitude of the current flowing into the capacitor from the input terminal 434 and the output terminal 436 is If the direction is used, the following formula of ■RCB for time can be derived by direct differentiation and integration or by using Laplace transform.

By adding the .multidot.RCB of each branch and setting the sum to zero, the time t for which RC delay circuit 410 activates operational amplifier 413 in interface 412 can be determined.

The presence of the Zenata diode Z440 is to raise the voltage at the output terminal 438 of the operational amplifier 413 sufficiently above the voltage oUT to prevent the monostable multivibrator 414 from operating during the charging period of the RC delay circuit 410. .

When operational amplifier 413 responds to RC delay circuit 410,
The potential at the output terminal 438 of operational amplifier 413 drops almost instantaneously to provide an operating signal for operating monostable multivibrator 414 .

Monostable multivibrator 414 provides a positive pulse to counter 444 and transistor T422 at the end of the fixed time interval.

When the transistor T422 is conductive, the transistor T41
4°T416. T418 and T420 are made conductive and the capacitor in RC delay circuit 410 is discharged.

When the capacitor discharges, the potential at output terminal 436 decreases.

The monostable multivibrator 414 has a delay time TD
At the end of 2 the transistor T returns to its low output state again.
414 to T422 are made non-conductive, and the RC delay circuit 41
0 repeats its timed action.

Monostable multivibrator 414 supplies one positive pulse to counting circuit 406 .

Counter circuit 406 then provides an output voltage signal when it receives a predetermined number of one-shot pulses.

The NE/5E555 monolithic timed circuit provides a suitable monostable multivibrator 414 and is manufactured by Signetics Corp.
commercially available from Poration).

As shown in FIG.
44, 446 and 447, and is connected with means for cascading these three counters in an appropriate order, ie, a comparator 448.

The large number of counts available with RC delay circuit 410 having a relatively small RC time constant is desirable for increased accuracy.

A suitable RC time constant range for RC delay circuit 410 is 0
．． 5 ms to 5 ms.

A suitable counting range for counter 444 is 500-40
It is 00.

This relationship determines the time scale criterion.

A binary counter 444 is particularly preferred, and a suitable counter advances on the negative transition of the one-shot pulse and R
RCA binary counter commercially available from CA Company/
This is a divider CD4040AE.

Comparator 4, which is the second unit of the above-mentioned MC3302P
48 (the first unit was used for comparator 408) has its negative input terminal connected to counter 444 via selector switch 452, and its output terminal connected to the counting input terminal of decimal counter 446.

The binary counter is configured to provide an output pulse every desired number of operations of the monostable multivibrator.

The desired number differs for each terminal of selector switch 452.

Counter 444 is reset to an initial or starting state by a normally sufficient positive signal provided by comparator 408 and released from the reset state to perform a clocking operation in which the comparator output signal is reduced.

Counters 446 and 447 may take the form of decimal counters, thereby allowing binary counter 444
You can choose the number of output pulses (required to activate the trip circuit) from the

These counters 446 and 447 are connected to trip circuit 600.
Select one of a group of time-current curves to control the operation of the .

The 10 position selector switches 450, 451 each have 10 positions so that <100 different time curves based on the time scale reference curve are obtained to make accurate selections.
It is connected to advance counters 446 and 447.

Counters 446 and 447 each selector switch 4
When providing positive output pulses to 50 and 451, third diodes D462 and D464 are both reverse biased to activate comparator 454.

This comparator 454 may be the third unit of the MC3302P with comparators 408 and 448.

The decimal counter may be of the type commercially available from RCA as CD4017AE.

Time/current curves 426-432 are used to replicate the current counter-time/current curves of very convenient electro-mechanical overcurrent relays, such as the CO relays currently manufactured by Westinghouse and commercially available. A trip curve 424 can be selected to have an almost unlimited number of shapes.

The required resistor and capacitor values are determined simultaneously by defining multiple time/current relationships on the curve to be replicated and according to the IRcB equations described above. You can get it by doing this.

The instantaneous trip detection circuit 500 immediately activates the circuit breaker 4 after the line current of the line conductor L1゜L2t or L3 and therefore the DC voltage of the peak voltage averaging circuit 200 exceeds a predetermined value.
Provides an output voltage signal for tripping.

As shown in FIG. 6, the instantaneous trip detection circuit 500
Resistors R502 and R504 for voltage division, adjusting resistor R506, filter capacitor C508, and resistor R
510, a comparator 512 (which may be the fourth unit of MC3302P), and a Zener diode z514 for overvoltage protection.

Comparator 512 provides a negative direction signal to trip circuit 600 when the voltage level at the terminals of capacitor C 508 reaches a magnitude equal to .

The movable arm of the rheostat R506 is the peak voltage averaging circuit 20.
DC voltage from 0 (this is instantaneous trip detection circuit 500
(necessary to operate).

Delay detection circuit 4004 or instantaneous trip detection circuit 500
a suitable trip circuit 600 for energizing the trip coil 6 of the circuit breaker in response to a negative direction signal from the circuit breaker;
is shown in FIG.

The trip circuit 600 includes an indicator circuit 6022, a circuit breaker activation circuit 604, and an indicator reset circuit 606.

The voltage drop at the output terminal of instantaneous trip detection circuit 500 causes base drive current to flow through transistor T608 (PNP), Zener diode Z614, resistor R616, and comparator 512.

This base drive current causes transistor T608 to raise the potential at node 618 to effectively 8+.

Current then flows through three conductors 620, 622 and 624 separately.

The current in conductor 620 is passed through diode D626 and resistor 628.
and flows through comparator 512 to ground.

This feedback loop connects line conductors L1. At 1, the line currents in L2 and L3 are interrupted by circuit breaker 4, keeping comparator 512 energized.

Current in conductor 622 flows through diode D 630 and circuit breaker activation circuit 604 .

This current flows in circuit breaker activation circuit 604 through resistor R632 and diode D634 to the gate of thyristor 5CR636.

When conducting, the energized thyristor 5CR636 connects the positive terminal 638 of the storage battery 640 to the diode D642.
, thyristor 5CR636, diode D644, normally closed contact 52a of circuit breaker 4, and trip coil 6
completing the current conduction path through which the current flows to negative terminal 646.

Trip coil 6 trips circuit breaker 4 when energized.

To prevent thyristor 5CR636 from firing due to noise or leakage current, capacitors C648 and C65
0 and a resistor R652 are provided.

The normally closed contact 52a is placed on the circuit breaker 4 and is opened when the circuit breaker 4 trips to interrupt the current flowing through the tidal rib coil 6 and thyristor 5CR636.

The circuit breaker actuation circuit 604 further includes a resistor R654 having a negative voltage-resistance characteristic to absorb signals due to transient energy present at the positive terminal 638 of the storage battery 640 and stored in the trip coil 6. Resistor R65 is used to release the inductive energy if it has not been consumed when the circuit breaker 4 is re-energized.
8 and an energy emitting circuit 656 consisting of a diode D660.

Indication circuit 602 instructs only after 5CR 636 is energized.

An instantaneous trip occurs when the current in conductor 624 flows through diode D66.
2. Electrically resettable instantaneous trip indicator 664
, two-position switch 666 with indicator reset and set positions, diode D668, normally closed contact 52a
, trip coil 6, storage battery 640, diode D 642, thyristor 5CR 636 and common bus 667 to ground.

Momentary trip indicator 664 is shown as a light reflective electromagnetic state indicator with inherent memory to maintain its indicated state even when its energization current is increased by opening of normally closed contact 52a.

The instantaneous trip indicator 664 therefore continues to indicate at one which is reset once activated.

A suitable instantaneous trip indicator 664 is a Ferranti-Packard
Commercially available from Limited.

The operation of the trip circuit 600 in response to the 0 negative going signal from the delay detection circuit 400 is generally the same.

The voltage drop at the output terminal of comparator 454 (FIG. 3) causes base drive current to flow through PNP transistor T670, Zener diode Z676, and resistor R678.

This base drive current causes transistor T670 to conduct, causing current to flow, thereby raising the potential at node 680 by, in effect, 8+1.

Current flows through conductors 682 and 684.

The current in conductor 682 is passed through diode D686 and resistor R63.
2 and through diode D634 and conducts thyristor 5CR636 to energize trip coil 6 in the manner described above.

The current in conductor 684 is connected between ■8+ and common bus 667 through diode D688, electrically resettable delay trip indicator 689, switch 666, and diode D688.
, normally closed contact 52a, trip coil 6, storage battery 640, diode D642 and thyristor 5CR6
Flows through 36.

Delayed trip indicator 689 is instantaneous trip indicator 66
Roughly the same as 4, once activated it remains activated at 1 which is reset.

During the initial operation of the relay when the voltage to ground at the output terminal 152 of the power supply circuit 148 (FIG. 2) has not reached the normal operating value of 1.8+, the circuit breaker 4 is inadvertently tripped. To prevent this, a Zener diode Z614 and a HiZ676 are provided.

The breakover voltage values of these Zener diodes z614 and Z676 should be high enough to prevent current from flowing during this period.

Conductor 690 is connected to conductor 682 such that limiter circuit 186 and thyristor 5CR 636 in circuit breaker activation circuit 604 are energized simultaneously.

The limiter circuit 186 includes contacts 8 and 10 of the circuit breaker 4.
During the period before the line current is cut off by opening of SAKAI and 12, circuit components are prevented from failing due to high voltage.

Current flows from connection point 680 to diode D686 to conductor 68
2 and 690, resistor R691 and diode "D6
Thyristor 5CR in the limiter circuit 186 through 92
190 (FIG. 2).

The thyristor 190 connects the output conductor 184 to ground when conducting and thus connects the load resistors R146, R170:b and R
172 (Figure 2).

Instantaneous trip indicator 664 and delayed trilough indicator 6
The indicator reset circuit 606 for 89 includes a resistor R693 and a capacitor C energized from a storage battery 640.
694.

These resistors R693 and capacitors C694 connect instantaneous trip indicators 664 and delayed trip indicators 689.
Provided to reset.

When switch 666 is in its reset position, capacitor C694 connects instantaneous trip indicator 664, delayed trip indicator 689, and resistors R695 and R696, respectively.
It is discharged to the earth through the Zener-Taioh)"Z 698.

This Zenata” ioode Z698 is trip circuit 6.
Except during the 00 reset operation, the breakover voltage level is high enough to prevent conduction to ground.

It is believed that the DC voltage signal from the peak voltage averaging circuit 200 continues to rise at 1 after activating the delay detection circuit 400, reaching a magnitude sufficient to also activate the instantaneous trip detection circuit 500.

To prevent this condition from occurring, diode D699 is connected to the negative input terminal of comparator 512 and resistor R678.
, and the connection point between the Zener diode z676.

When comparator 454 (FIG. 3) in delay detection circuit 400 provides a negative going signal, the cathode of diode D 699 is at a low enough potential to prevent operation of comparator 512 in instantaneous trip detection circuit 500. , which causes transistor T608 to conduct and instantaneous trip indicator 66 to turn on.
Empower 4.

Therefore, the instruction circuit 602 determines which of the delay detection circuit 400 and the instantaneous trip detection circuit 500 is the trip circuit 600.
can indicate when it was first activated.

FIG. 7 shows a modification of the input circuit of FIG. 2.

To simplify the description of this modified input circuit 700, current transformers CT2 and CTa and their associated circuits have been omitted since they are virtually the same.

Thyristor 5CR136 and its associated circuits (i.e. the two diodes of full-wave rectifier bridge RE110, resistor R144 and capacitors C166 and C168) are connected to thyristors 5CR702 and 704 and their associated circuits (i.e. capacitors C706, C708 and C710 and resistor R712).

The input circuit 700 of the modified example is configured to input the information winding 10 of the current transformer CTI every time the line current of the line conductor L1 crosses zero.
Make sure to disable 6.

As mentioned above, the thyristor 5CR13 shown in FIG.
6 is designed to turn off as long as the rectified output current at its anode decreases and is less than a predetermined magnitude for at least the shortest shut-off time.

If the first derivative of the magnitude of the anode superposition with respect to time is such that the current is not maintained below the predetermined level mentioned above for the shortest shut-off time, the thyristor will never become non-conducting. .

However, if the pair of diodes in the full-wave rectifying bridge RE110 are replaced by a pair of thyristors 5CR702:b and 70 as illustrated in the full-wave rectifying bridge RE710,
4, each thyristor receives an alternating voltage at its anode.

When conducting, thyristor 5CR702 is a full-wave rectifier bridge R
If the upper terminal of E710 is positive, thyristor 5CR702 is connected between the information winding 106 and the grounded common bus.
and provides a current carrying path for current flowing through resistor R146.

Similarly, when conducting, the thyristor 5CR704 has the information winding 1
Thyristor 704 between 06 and the grounded common bus
and provides a current carrying path for current placed through resistor R146.

The operation of input circuit 700 is similar to input circuit 100 of FIG. 1 in terms of its music, and will be clear from the description of its operation with respect to FIG.

FIG. 8 shows another modification of the input circuit 100.

This alternative input circuit 800 includes a dual regulated power supply circuit for supplying positive and negative regulated supply voltages to a detection circuit 804 that requires these supply voltages.

The input circuit 800 is not rectified and the line conductors Ll, L
2 and L3.

In order to simplify the explanation, only one of the three phases will be illustrated and explained as in the case of FIG. 7.

Current transformer CT4 has a power winding 806 and an information winding 808 as secondary windings and an input winding 81 as a primary winding.
has 0.

The human winding 810 is energized in response to the line current in the line conductor L1.

The number of turns N2 in the information winding 808 is greater than the number N1 of turns in the power winding 806.

Center tap 812 on power winding 806 is grounded.

For ease of explanation, it is assumed that the line current in line conductor L1 has just crossed the zero point and power winding 806 is energized;
Assume then that information winding 808 is not energized and therefore triac 844 is non-conducting.

When a line current flows through the line conductor L1 in a direction that lights up the lower end of the power winding 806 and makes the upper end positive (hereinafter referred to as a "positive half cycle"), the current to charge the capacitor C816 flows through the capacitor C816. C816 ground end and power winding 8
06 to grounded center tap 812 through capacitor C816, diodes D818 and D820, and the lower half of power winding 806.

The current for charging capacitor C826 is the power S line 8
06 between the grounded center tap 812 and capacitor C826 through the upper half of power winding 806, diodes D822 and D824, and capacitor C826.

During the opposite or "negative half cycle" of line current flowing through line conductor L1, current flows from power winding 806 to diode D820. Diode D instead of D8220
828. capacitor C816 through D830 respectively
, charge the C826.

In other words, during the "positive half cycle" capacitor C816 is charged from the lower half of power winding 806 and capacitor C826 is charged from the upper half of power winding 806.

During the negative half cycle, the relationship between the capacitor and each half of the power winding is reversed.

The current flowing through each half of power winding 806 may or may not be equal.

The reason is that the total ampere-turns of power winding 806 is equal to the total ampere-turns of input winding 810, and the current division in each half only needs to be dictated by the state of charge of capacitors C816 and C826. It is from.

Control circuit 814 is provided to regulate the supply voltage described above and to control the sequential operation of power winding 806 and information winding 808.

The control circuit 814 includes a voltage regulating element Z832 such as a Zener diode, a switching element T834 such as an NPN) transistor, a capacitor C836, and a resistor R.
838, R840 and R842, and Triac 84
4.

The term triac as used herein means any switching element having a first terminal or anode, a second terminal or cathode, and a third terminal or gate and exhibiting the following characteristics:

Current flowing through the gate causes the triac to conduct, allowing current to flow in either direction between the anode and cathode.

Once a triac begins conducting, it will not become non-conducting unless the current flowing between the anode and cathode decreases and remains below a predetermined magnitude for at least a minimum period of time.

Capacitors C816h and C826 are charged as described above so that eventually they both reach a predetermined magnitude equal to the breakover voltage value of Zener diode Z832.

When this condition occurs, the current flows through the Zener diode Z832
, flows through resistor R840 and the base of transistor T834.

Transistor T834 conducts and current flows through the gate of triac 844, resistor R842, and transistor T83.
4, flows through diode D820t or D828 and half of power winding 806.

Transistor T834 can conduct during either the "positive half cycle" or the "negative half cycle" of the current transformer.

Diodes D818 and D824 are connected to transistor T
834 temperature compensation and capacitor C816b
and 826 are further adjusted.

Diode D818 isolates capacitor C816 from transistor T834t or T832(7) leakage current.

When conducting, the energized triac 844 connects the information winding 8
08, operates information winding 808 by providing a current path through triac 844 and load resistor R846.

This, in turn, causes the voltage across the power winding 806 to drop.

Then, the diode D820. D822. D828
The rectifier means received from D830 is reverse biased to effectively terminate the current flowing through power winding 806.

The main difference between the input circuits in Figures 2 and 8 is that the load resistance R8
46 provides an electrical quantity responsive to the alternating current line current in line conductor L1.

The triac 844 is the thyristor 5CR13 in FIG.
6, it becomes non-conducting every half cycle of the line current,
Therefore, information winding 808 is deactivated or opened, and power winding 806 is activated to charge capacitors C816 and C826 each half cycle.

FIG. 9 shows an example where current transformer CT5 has only one output winding.

As shown, the winding-core relationship of current transformer CT5 is such that the core saturates within the expected current value range of the AC circuit.

In order to simplify the explanation, the input circuit 900 is
Only the phase is shown.

The saturable current transformer CT5 has a primary winding or human winding 90 energized with an amount of electricity proportional to the line current of the line conductor L1.
2 and a secondary or output winding 904 .

This output winding 904 energizes resistors R908 and R909 connected in series with each other via a full-wave rectifier bridge RE906.

Power supply circuit 148 connects resistors R908 and R90 through regulation path 910 and human overvoltage protection circuit 912.
evening diodes D914 and D91 connected in parallel with 9 to one output terminal 926 of the full-wave rectifier bridge RE 906.
5 blocks any power flowing back from the power supply circuit 148.

The current transformer CT5 is 2PU with twice the current of the current transformer circuit.
) or designed to saturate with a current corresponding to any desired lightning level.

For ease of explanation, it is assumed that the line current in line conductor L1 has just crossed zero and that the energy storage elements or capacitors C150 and C164 in power supply circuit 148
(Figure 2) Let's assume that the battery is initially in an uncharged state.

When human power winding 902 is energized, it conducts current through output winding 904 which is rectified by full wave rectifier bridge RE 906 .

Output terminal 924°926 of full wave rectifying bridge RE906
are each connected to a grounded common bus, conductor 928.

Initially, capacitors C150 and C164 are completely discharged, the impedance of power supply circuit 148 is smaller than the combined impedance of resistors R908 and R909, and most of the rectified output current is at output terminal 92.
6 through conductor 928 to power supply circuit 148 .

For line current values less than 2 PU, current flows for one or more cycles to charge the power supply circuit 148.

The number of cycles required depends on the magnitude of the line current and the capacitance of capacitors C150 and C164.

Eventually, the voltage at the terminals of the capacitor (and the voltage across the series connected resistors R908b and R909) reaches the desired value, positive voltage ■ + and reference voltage ■.

supply. When this occurs, regulation circuit 910 is activated, thereby directing current from conductor 928 through resistor R94 (1) and Zener diode Z936 to ground.

The adjustment circuit 910 is an NPN) transistor T930°T9.
32 and T934, Zener diode z936 for voltage adjustment, and resistors R938, R940 and R942
Equipped with.

Initially, transistor T930 conducts and provides base drive current to transistor T932, which causes transistor T932 to create a low impedance connection between conductor 928 and power supply circuit 148 to correct the charging current as described above. maintain.

When the transistors are connected as shown, a large current flows through transistor T932 in response to a small value current flowing into the base of transistor T930.

When the magnitude of the voltage of the power supply circuit 148 reaches its desired value, the potential of the quad 92B reaches the Zener diode z936.
becomes high enough to break over and cause current to flow through resistor R940.

This will restore the base drive current to transistor T934, causing it to conduct.

Transistor T934 conducts and transistor T930
When lowering the base potential of the transistor T932 and reducing the conductivity of the transistor T932, the current passing through the transistor T932 becomes large, that is, the Zener diode Z936
Equilibrium is established such that the magnitude decreases by 1 (the magnitude required to maintain the desired voltage value of the power supply circuit 148, as determined by ).

If the drain current in power supply circuit 148 is
5, the main current flows through load resistors R908 and R909.

Resistors R908 and R909 provide a voltage divider circuit;
and its relative magnitude depends on the relative magnitude of the voltage of power supply circuit 148 and the desired output voltage range of peak voltage averaging circuit 200.

The voltage across resistor R909 is the voltage across any one line conductor L1. An information signal responsive to the magnitude of the maximum line current of L2t or L3 is provided to the highest voltage signal supply circuit 174 and hence to the peak voltage averaging circuit 200.

Zenata" diode Z936 was a temperature compensating element and regulated the voltage of power supply circuit 148.

Does this happen with the diode D911? and D915
This is because the temperature effect of the base-emitter junction of transistor T932 is canceled out.

Input overvoltage protection circuit 912 prevents overvoltages caused by large fault currents from destroying circuit components.

The human overvoltage protection circuit 912 is a Zener diode Z9.
46, NPN) transistors T948 and T950, and resistors R952°R954 and R956.

A second series connected transistor state consisting of transistors T948 and T950 is connected to a Zener diode 29.
When 46 is conductive, conductor 928 is grounded.

A suitable magnitude for Zener breakover voltage VZ946 may be 200 volts.

Using a saturable current transformer that saturates over the normal operating range can reduce the load on the current transformer, and also provides a counter-timed current response in a current input range that is greater than the saturation current value. can be obtained.

In this regard, it is recalled that as the size of the input terminals to the current transformer increases, the saturation current value will be reached within a short period of time.

The magnitude of the current pulse in the output winding is determined by the rate of change of the current transformer flux (
The peak value of the voltage across the load resistor increases as the magnitude of the input current increases.

In this range below the saturation value this is a linear relationship;
And of course the output current tracks the input current through each half cycle.

When the magnitude of the input terminal increases above the saturation value of the iron core, the current flows at an increasing rate of change to follow the increasing rate of change of the input current, but only for a portion of each half cycle, and of course no human power The strain on the windings is greatly, but not completely, reduced during the period when no current is flowing in the output windings.

Since operation of the current transformer in the saturation region provides a constant rms output superposition, such a configuration utilizes the peak value to sense the magnitude of the input current during the saturation region.

Although an example using a saturable current transformer is shown in FIG. 9, a dual output winding in which the windings are used sequentially during each half cycle can also be used in the electrical quantity response device of FIG.

When using a two output winding configuration, the current transformer must saturate only during the period that the magnitude sensing winding is utilized.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a protective relay incorporating the electrical device according to the present invention, Fig. 2 is a circuit diagram of the input circuit shown in the block diagram in Fig. 1, and Fig. 3 is a block diagram of the input circuit shown in Fig. 1. A circuit diagram of the peak voltage averaging circuit and delay detection circuit shown in the figure,
Figure 4 is a semi-logarithmic graph showing how to shape the desired counter-timed response curve using overlapping techniques; Figure 5 is a graph useful in explaining RC delay circuits used in delay detection circuits; 6 is a circuit diagram of the instantaneous trip detection circuit and trip circuit shown in the block diagram in FIG. 1, FIG. 7 is a circuit diagram of a modification of the input circuit shown in FIG. 2, and FIG. 8 is a circuit diagram of a modified example of the input circuit shown in FIG. FIG. 9 is a circuit diagram of another modified example of the input circuit shown in FIG. 2, and FIG. 9 is a circuit diagram showing a partial block diagram of an example of a protective relay battery. 200 is a peak voltage averaging circuit as an input means; 40
0 is a delay detection circuit, 410 is an RC delay circuit, 434 is R
436 is an input terminal of the C delay circuit, 436 is an output terminal of the RC delay circuit, 404 is a pulse generation circuit, and 406 is a counting circuit.

Claims (1)

[Claims] 1 In order to perform a predetermined voltage vs. time response, the system comprises an input means for receiving a DC voltage, and a delay detection circuit connected to the input means and supplying an output quantity of electricity with a delay time depending on the magnitude of the DC voltage. , the delay detection circuit includes an RC delay circuit having a plurality of parallel branches connected between an input terminal and an output terminal, a pulse generation circuit and a counting circuit,
Each of said parallel branches provides a predetermined branch voltage output having an anti-timed characteristic, the sum of said branch voltage outputs being adapted to energize said pulse generating circuit with a Re delay. The RC delay circuit provides a circuit voltage signal, the RC delay circuit is connected such that its input terminal is responsive to the DC voltage supplied from the input means, and has an output responsive to the DC voltage at its output terminal. and the pulse generating circuit supplies a pulse when the output of the RC delay circuit reaches a predetermined value, and this pulse causes the counting circuit to count up, and also resets the RC delay circuit to restart the above. an electrical device for performing a predetermined voltage versus time response in response to a direct current voltage, the counting circuit supplying the output quantity of electricity when receiving a predetermined number of pulses from the pulse generating circuit; .