JPH0763205B2 - Distribution line accident detection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a distribution line accident detection device, and more particularly to an accident detection circuit technology capable of detecting a distribution line accident and taking a desired action.

[Prior Art] Conventionally, the directional accident detection of a distribution line is based on the position of the distribution line where the detection device is installed, and the power is supplied when an accident occurs on the distribution line from the device installation position to the substation. On the contrary, when the accident occurred on the load side of the device installation position, it was judged as the load side and the direction of the accident was judged.

However, it is necessary to manually switch the polarity changeover switch of the accident detection device when the relative position between the substation and the phase of the installation of the accident detection device changes by switching the substation for adjustment of load flow etc. Met.

In addition, when a current transformer is used to detect such an accident, four or more current transformers are used, the number of installed current transformers is large, and a compact device (column) for distribution lines and It hampered the economics of the device.

Furthermore, it is difficult for the conventional detection device to detect all of the range from the small current to the large current, and there is nothing that can detect an accident even in a no-load state where a small amount of current flows. .

[Problems to be Solved by the Invention] An object of the present invention is to provide a technique capable of measuring from a small current region to a large current region.

It is another object of the present invention to provide a technique capable of reducing the number of installed current transformers, realizing a compact mounting pole for a distribution line, and realizing economical efficiency of an accident detection device.

The present invention further provides a technology capable of automatically determining the direction of the substation and automatically switching the power transmission direction when the substation is switched in order to adjust the load flow of the distribution line. The purpose is to provide.

The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[Means for Solving the Problems] The outline of a typical invention disclosed in the present application will be briefly described as follows.

In the present invention, a current transformer and a transformer are connected to each phase of a polyphase distribution line, for example, a three-phase distribution line.

The current transformer detects each phase current, the transformer detects each phase voltage, and these detection signals are sent to the phase determination circuit that determines the fault direction and enables automatic switching of the power transmission direction. However, at the intermediate connection connecting these two, between the secondary winding terminals (loop) of one of the three current transformers,
Resistors having different resistance values should be connected in series. One of the resistors is one resistor (load resistor) connected between the terminals of the secondary windings of each of the three current transformers, and the other resistor (micro current value detection resistor). Has a resistance value that is, for example, 10 to 2000 times the load resistance.

While taking out the detection voltage signal between the terminals of each load resistance in these three load resistances and sending it to the phase determination circuit,
The detection voltage signal between terminals of the minute current detection resistor is taken out and sent to the phase determination circuit. This becomes the phase current (I _r ).

Further, the current synthesizing resistor is connected to the system (between the loops described above) for synthesizing the currents flowing through these load resistors, the inter-terminal detection signal of the current synthesizing resistor is taken out, and selected in the phase determination circuit.

This is the zero-phase current (I _o ).

On the other hand, the transformer is composed of a capacitor type transformer,
Combined with a high voltage dividing capacitor and a detecting voltage dividing capacitor, the electrolytic drop of the detecting voltage dividing capacitor is sent to the primary winding of the transformer provided in the intermediate connection section, and the secondary winding of the transformer is connected. The combined voltage of the lines is sent to the phase judgment circuit to make the zero-phase voltage (V _o ) of the three-phase distribution line, and the transformer that is electromagnetically coupled with the primary winding of the one-phase transformer in these three-phase distribution lines. The induced voltage of the tertiary winding of the transformer is sent to the phase judgment circuit and used as the phase voltage (V _r ).

An accident is determined by comparing the phases of the phase voltage (V _r ) and the zero phase voltage (V _o ) with the zero phase current (I _o ) and the phase current (current flowing through the load resistance) (I _r ). At that time, as described above,
Since the terminal detection voltage signal of the minute current detection resistor is also sent to the phase determination circuit, the phase comparison with this is also performed.

In addition to the amplifier, the phase determination circuit includes a phase comparator, a power transmission direction determination switching device, a power transmission direction switching switch, and the like. These have the function of automatically determining the direction of the substation and automatically switching the power transmission direction between the power source side and the load side at the accident detection device installation position.

Further, the power transmission direction discrimination switching device in the phase determination circuit is provided with a display function capable of displaying the accident only when the accident occurs on the load side.

In the present invention, in the intermediate connection part, a new current transformer is installed at the position of the minute current detection resistance, and the primary winding of this current transformer is connected in series with the load resistance described above, and the secondary current of the current transformer is connected. A minute current detection resistor may be connected between both terminals of the winding.

Further, in the present invention, it is preferable to connect an anti-parallel connection diode in parallel to the minute current detection resistor at the intermediate connection portion.

[Operation] In the present invention, three current transformers and the same number of capacitor-type transformers are connected to the three-phase high-voltage distribution line, and the secondary winding of the one-phase current transformer among these current transformers is connected. Connect the minute current detection resistor in series with the load resistor connected to the winding, and set the resistance value of the minute current detection resistor to
If set to 2000 times, if currents of the same amplitude flow through these resistors, the voltage drop of the minute current detection resistor will be the above multiple of the voltage drop of the load resistor, and the voltage drop across the minute current detection resistor will be phase-judged. When applied to the amplifiers of the circuit, the outputs of these amplifiers have a resistance ratio multiple, even if they have the same amplification factor as the amplifier that applies the voltage drop across the load resistor.

In this way, by applying the voltage drop of the load resistance and the voltage drop of the minute current detection resistor to separate amplifiers, a small current of, for example, 20 to 200 mA can be detected from the minute current detection resistor. It is possible to detect a large current of about 20 to 600 A from the voltage drop of the load resistance, and from a small current when there is no load to 600 A when a short-circuit accident occurs.
Line currents can be detected over a wide range, up to high currents of the order of magnitude or more.

As described above, even when a new current transformer is connected, it is possible to detect a line current in a wide range in the same manner by appropriately selecting the current transformation ratio of the current transformer.

Thus, between the secondary winding terminals of the one-phase current transformer of the three current transformers, a load resistor with a small resistance value and a minute current detection resistor with a large resistance value are connected in series. Since the voltage drop of is amplified by separate amplifiers in the phase determination circuit, from small currents (including minute currents) to large currents, only three current transformers can be connected to each phase of the distribution line for measurement. In this measurement, the number of installed current transformers can be reduced as compared with the case where four or more current transformers have been conventionally used, and a compact distribution pole of a distribution line and an accident detection device can be performed. The economy of can be realized now.

Also, by connecting an anti-parallel connection diode in parallel with the minute current detection resistor, the voltage across the resistor can be clipped to a certain value or less, and the phase determination can be performed even if a large line current flows in the system. The amplifiers in the circuit can be protected against breakdown, which allows the fault detection device to be fully operational over a wide range of line currents.

Furthermore, the current-combining resistor provided between the secondary winding terminals of the one-phase current transformer of the three current transformers detects the zero-phase current and is useful for phase comparison. , The residual current of the zero-phase current is suppressed, noise is reduced, and highly accurate detection is enabled.

Furthermore, the voltage drop of the voltage dividing capacitor for detection of the capacitor type transformer is sent to the primary winding of the transformer at the intermediate connection part, and the zero-phase voltage of the three-phase distribution line is passed through the secondary winding of the transformer. To the phase determination circuit, and further, by transmitting the phase voltage to the phase determination circuit via the tertiary winding of the one-phase transformer in the same transformer, the minute current detection resistor having the above circuit configuration is provided. Phase comparison with the load resistance connected in series with this or other load resistance or the detection voltage signal between the terminals of the current synthesis resistance enables detection of faults under both small and large currents. In particular, since a minute current detection resistor is provided and the voltage drop due to this is detected, even if a very small healthy current such as 200 mA flows through the distribution line, the phase comparison with the above phase voltage causes the power transmission of the phase determination circuit. It is possible to drive the direction determination switching device and the power transmission direction switching switch. According to the switching device and the switch, the power transmission direction of the accident detection device can be automatically switched in response to the switching of the distribution line for complicated load flow adjustment, and the direction of the ground fault can be determined. .

Further, the fact that an accident has occurred can be displayed by the switching device.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a system diagram of an accident detection circuit according to the present invention. The three-phase distribution lines R, S, T are shown as examples.

In the figure, 1 is a sensor section, and three sensors 1A, 1B and 1
It is composed of C. Reference numeral 2 is an intermediate connection portion, 3 is a phase determination circuit, and an example of its detailed configuration is shown in FIG.

Each of the sensors 1A, 1B, 1C has a current transformer and a capacitor type transformer.

The current transformer 4 in the sensor 1A is connected to the distribution bus R, the current transformer 5 in the sensor 1B is connected to the distribution bus S, and the sensor
The current transformer 6 at 1C is connected to the distribution bus T.

In the sensor 1A, the capacitor type transformer 1 including the high voltage dividing capacitor 7 and the detecting voltage dividing capacitor 8 is connected to the distribution bus R, and the high voltage dividing capacitor 9 and the detecting voltage dividing capacitor 10 in the sensor 1B are connected. Is connected to the power distribution bus S, and the capacitor type transformer including the high voltage dividing capacitor 11 and the detecting voltage dividing capacitor 12 in the sensor 1C is connected to the power distribution bus T.

Each of these capacitor type transformers is grounded to a common ground 13.

In the present invention, in the three-phase high voltage distribution line, three current transformers 4,
It is intended to detect accident information on the distribution line only with 5, 6 and 3 capacitor type transformers.

Between the terminals of the polarities k and 1 of the secondary windings of the respective current transformers 4, 5 and 6, in the sensor 1A, the anti-parallel connection diodes 14, 1
5, the antiparallel connection diodes 16 and 17 are similarly connected in the sensor 1B, and the antiparallel connection diodes 18 and 19 are further connected in the sensor 1C.

This makes it possible to protect the amplifier in the phase determination circuit 3 from being destroyed even when the line current becomes large.

In FIG. 1, reference numerals 20, 21, and 22 are cables, and the outer skin is grounded to the ground 13.

The terminals of the secondary windings of the current transformers 4, 5 and 6 with the polarity 1 are connected to the connection wire 1N,
Connect to the neutral line N ₁ via 2N and 3N, respectively.

The terminal of polarity k of the secondary winding of the current transformer 6 connected to the wiring bus T is connected to the neutral wire N ₂ via the load resistance R ₂₉ by the connection wire 23 and connected to the wiring bus S. The terminal of the secondary winding 5 of polarity K is connected to the neutral wire N through the load resistance R ₃₀ by the connecting wire 24.
The terminal of the secondary winding of the current transformer 4, which is connected to ₂ and is connected to the wiring bus R, of polarity k, is connected to the neutral line N ₂ via the load resistance R ₃₁ by the connection line 25.

A current combining resistor R ₃₃ is connected between the neutral wire N ₂ and the neutral wire N _1, and anti-parallel connection diodes 34 and 35 are connected in parallel with the current combining resistance R ₃₃ .

A small current detection resistor R ₃₂ is connected between the terminal of the secondary winding polarity k of the R-phase current transformer of the current transformers 4 to 6 and one terminal of the load resistor R ₃₁ to connect the load current resistor R _32. R ₃₁ and micro current detection resistor R ₃₂
The node of is set to 28. Anti-parallel diodes 36 and 37 are connected in parallel to the minute current detection resistor R ₃₂ .

26 and 27 are also nodes.

In Fig. 1, 38, 39 and 40 are temporary windings of the transformer, and 48
Is a transformer tertiary winding electromagnetically coupled to the temporary winding of the transformer 38, and 49, 50, 51 are primary windings of the transformer 38, 39, 40.
Is the secondary winding of the transformer.

The inter-terminal detection voltage signal of the current synthesis resistor R ₃₃ is sent to the terminal 88 of the phase determination circuit 3 as the zero-phase current I _o .

The inter-terminal detection voltage signal of the load resistor R ₃₁ is sent to the short-circuit current input terminal 89 of the phase determination circuit 3 as a phase current (short-circuit current) I _r through the connection line 43.

The detection voltage signal between the terminals of the minute current detection resistor R ₃₂ is
2, the phase current I _A is sent to the terminal 90 of the phase determination circuit 3.

The inter-terminal detection voltage signal of the load resistor R ₃₀ is sent to the short-circuit current input terminal 91 of the phase determination circuit 3 as a phase current (short-circuit current) IS through the connection line 44 drawn from the node 27.

Terminal between the detection voltage signal of the load resistor R ₂₆ is the connecting line 45 drawn from the node 26, the phase current (short circuit current) to the short-circuit current input terminal 92 of the phase determination circuit 3 is sent as I _t.

Series connected capacitors 7 and 8, 9 and 10,
The voltage drop across the voltage dividing capacitors 8,10,12 of 11 and 12 is delivered to the transformer primary windings 38,39,40.

Transformer secondary winding 49, 50, 51 is connected delta, the zero-phase voltage V _o of the three-phase distribution line RST sends out a differential voltage to the terminal N and the terminal 94 of the phase determination circuit 3.

The induced voltage by the transformer tertiary winding 48 electromagnetically coupled to the R-phase transformer primary winding 38 is sent to the terminal N and the terminal 93 of the phase determination circuit 3 to obtain the phase voltage V _r .

Terminal O ₁ and tertiary winding 48 terminal O ₃ of the transformer primary winding 38 is connected to the circuit 46, although not shown, connects the terminal N and the ground 13.

In the phase determination circuit 3, as described above, the phase voltage V _r , the zero phase voltage
Undergoing V _o to its terminals 93 and 94 respectively, the phase received on terminal 89,88 currents I _r, zero-phase current I0 and the phase comparator performs accident determination.

In FIG. 1, 85, 86 and 87 are arresters (lightning protection elements), and 41 is a multi-core cable.

Further, Ac indicates the power supply of the phase determination circuit 3, and SA ₁ and SA ₂ indicate surge absorbers, respectively. Next, the phase determination circuit 3 will be described together with its operation with reference to FIG.

In FIG. 2, 88 and 89 are the first terminals respectively as described above.
Common with the figure. As described above, the zero-phase current (I _o ) and the phase current (I _r ) are input to these terminals 88 and 89.

Further, in FIG. 2, 93 and 94 are also terminals, which are common to those in FIG. 1, and the phase voltage (V _r ) and the phase current (I _r ) are input.

Further, in FIG. 2, 63 and 64 are amplifiers and 6 respectively.
5, 66, 67, and 68 are filters (passing only the fundamental wave component), 69, 74 and 75 are level detection circuits, 70 and 71 are zero cross detection circuits, 72 and 73 are full wave rectification circuits, 76 is a direction change switch,
77 is a phase comparison circuit, 78 is an AND circuit, 79, 80, 81
Reference numerals 82 and 82 denote time circuits (comparing the accident duration with reference time), 83 denotes an OR (or) circuit, and 84 denotes a transmission direction discriminating and switching device [in addition to the function of switching the direction switching switch, there is also a display function. Hereinafter, it may be referred to as the display device 84].

In FIG. 2, the block configuration of only one terminal of the terminals 88 and 89 is shown, and the block configuration of the other terminal having the same configuration is omitted. Therefore, the terminal
The input signal from 88 and the input signal from the terminal 89 are input to the respective amplifiers 64 ... Terminal 9
The same applies to 3,94.

When the input current I _o or I _r is equal to or higher than the reference value in the level detection circuit 69 and continues to be equal to or higher than the set reference value in the time limit circuit 81, the display 84 indicates an accident.

The input current I _o or I _r and the input voltage V _o or V _r are compared with a reference value in the level detection circuits 74 and 75 via the filters 67 and 68 and then the rectifier circuits 72 and 73, and are compared with the reference value or more. At this time, the AND circuit 78 is driven. Meanwhile, the zero-cross detection circuit 7
Numerals 0 and 71 detect the zero cross of the input waveform, pass through the direction changeover switch, and the phase comparator 77 performs phase comparison. When the phase difference is within the predetermined range, the AND circuit 78 is driven. AND circuit 78
When the input condition is satisfied, the OR circuits 83 are driven in the time limit circuits 80 and 81 after a predetermined time has passed, and the power transmission direction discrimination switching device (display) 84 is driven. When the transmission direction discrimination switching device 84 operates, the transmission direction changeover switch 76 of the circuit having the zero-phase voltage V _o and the zero-phase current I _o is switched, and the polarity of the zero-phase voltage V _o is reversed to perform phase comparison. Drives circuit 77. Therefore, the relationship between the zero-phase voltage V _o and the zero-phase current I _o generated in the event of a ground fault is reversed at the installation position on the distribution line of each sensor 1A, 1B, 1C, and the conventional power supply side and load side The relationship is completely reversed, and the direction of the ground fault is determined based on the new load side and power source side conditions.

Since the phase current I _r for determining the power transmission direction is detected by the voltage drop of the minute current detection resistor R _{32 having} a large resistance value with respect to the load resistor R ₃₁ , a very small sound current such as 200 mA is generated on the distribution line. Just by flowing to RST, it is possible to drive the power transmission direction discrimination switching device 84 by comparing the phase with the phase voltage V _r, and corresponding to the distribution line switching operation for frequent load flow adjustment, the accident detection device The power transmission direction can be automatically switched.

Next, another embodiment of the present invention will be described with reference to FIG.

In the present invention, as shown in FIG. 3, a primary winding 96 of a current transformer (CTA) 95 is connected in series with a load resistor R ₃₁ , and the current transformer 9
A small current detection resistor R _{32 and} this resistor
The reverse parallel connection diodes 36 and 37 connected in parallel with R ₃₂ are connected, and one terminal of this secondary winding 97 is connected to the neutral line N ₂ . The other terminal of the secondary winding 97 is connected to the amplifier 64 via the terminal 90 of the phase discriminating circuit 3.

By appropriately selecting the current transformer ratio of this current transformer (CTA) 95, the voltage drop of the minute current detection resistor R ₃₂ can be reduced.
It can be set to, for example, 10 to 2000 times the voltage drop of ₃₁ .

The phase current I _r for determining the power transmission direction in this case is the voltage drop of the small current detection resistor R ₃₂ with a large resistance value connected to the secondary winding 97 of the current transformer 95 with respect to the load resistor R ₃₁ . Therefore, the power transmission direction discrimination switching device 84 can be driven by the phase comparison with the phase voltage V _r just by flowing a very small sound current such as 200 mA to the distribution line RST.
It can be operated in the same way as shown in the figure.

It should be noted that FIG. 3 shows only the main part, and other configurations are the same as those in FIG.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments and can be variously modified without departing from the scope of the invention. Nor.

For example, in the above-described embodiment, an example in which a minute current detection resistor R ₃₂ or the like is connected to the R-phase current transformer 4 and phase comparison using the phase current I _r is shown, but the same applies to the S-phase or T-phase. The circuit configuration may be adopted and the phase comparison may be performed.

[Effects of the Invention] According to the present invention, the three-phase high-voltage distribution line RST is connected to a capacitor-type transformer including three current transformers 1A, 1B, 1C and the same number of series-connected capacitors 7 to 12, These current transformers 1A, 1
A small current detection resistor R ₃₂ is connected to the secondary winding of the current transformer 1A of one phase (exemplified by R phase) of B and 1C, and a load resistor R connected to the winding.
_If it is connected in series with ₃₁ and the resistance value of the minute current detection resistor R ₃₂ is set to, for example, 10 to 2000 times the resistance value of the load resistor R ₃₁ , currents of the same amplitude flow through these resistors R ₃₁ and R ₃₂ . In this case, the voltage drop of the minute current detection resistor R ₃₂ is the above-mentioned multiple of the voltage drop of the load resistor R ₃₁ , and if the voltage drop across the minute voltage detection resistor R ₃₂ is applied to the amplifier 64 of the phase determination circuit 3, the load resistance is An amplifier that applies a voltage drop across R ₃₁ and 6
Even if the amplification factor is the same as 4, the output of the amplifiers 64 ... Has a resistance ratio multiple.

Thus, by the load resistor R ₃₁ of the voltage drop and the voltage drop of the small current detection resistor R ₃₂ each applied to separate amplifiers 64 ..., the small current detection resistor R _32, for example 20-2
Can detect small current of about 00MA, also, it is possible to detect a large current of about 20~600A from the voltage drop across the load resistor R _31, at the time of short circuit from small current during no-load It was possible to detect a wide range of line current up to a large current of about 600 A or other.

Further, even when the current transformer 95 is installed, it is possible to detect the line current over a wide range similarly by appropriately setting the current transformation ratio of the current transformer 95.

Thus, one of the three current transformers 4, 5 and 6 (exemplified by R phase)
Between the secondary winding terminals k and l of the current transformer 4, the load resistance R ₃₁ with a small resistance value and the minute current detection resistance R ₃₂ with a large resistance value are connected in series, and the respective voltage drops are phased. Since the amplification is performed by the separate amplifiers 64 in the determination circuit 3,
From small currents (including minute currents) to large currents, you can measure by simply connecting three current transformers 4,5, 6 to each phase R, S, T of the distribution line. Compared to the case where four or more current transformers were used in the past, the number of installed current transformers can be reduced, and the economic efficiency of the distribution pole and the accident detection device can be realized. .

Further, by connecting the anti-parallel connection diodes 36 and 37 in parallel with the minute current detection resistor R ₃₂ , the voltage across the resistor R ₃₂ can be clipped (fixed) to a certain value or more,
Even if a large line current (iR) flows in the connecting line 25, it is possible to protect the amplifier 64 in the phase determination circuit 3 from being destroyed, and this makes it possible to safely operate the accident detection device over a wide range of line currents. I was able to make it work.

Further, the current combining resistor R33 provided between the secondary wire winding terminals of the current transformer 4 of one phase (exemplified by the R phase) of the three current transformers 4, 5 and 6 is a zero phase current (I _o ) is detected and is useful for phase comparison, and the presence of this resistor R ₃₃ suppresses the residual current of the zero-phase current (I _o ) to, for example, about 60 mA (first-order conversion value) to reduce noise, It was possible to detect with high accuracy.

Furthermore, the voltage dividing capacitor for detection of the capacitor type transformer 8,
The voltage drop of 10,12 is sent to the primary windings 38,39,40 of the transformer in the intermediate connection 2, and the secondary windings 49,50,51 of the transformer are sent.
The zero-phase voltage (V _o ) of the three-phase distribution lines R, S, and T is sent to the phase determination circuit 2 via the three-phase distribution line, and the phase voltage is further transmitted through the tertiary winding 48 of the one-phase transformer in the same transformer. By sending (V _r ) to the phase determination circuit 2, a minute current detection resistor R ₃₂ having the above circuit configuration, a load resistor R ₃₁ connected in series with this, and other load resistors R ₂₉ , R ₃₀ and Phase comparison is performed with the detection voltage signal between the terminals of the current synthesis resistor R ₃₃ , enabling fault detection under both small and large currents. In particular, since a minute current detection resistor R ₃₂ is provided and the voltage drop due to this is detected, even if a very small sound current such as 200 mA flows through the distribution line, phase comparison with the above phase voltage (V _r ) The power transmission direction determination switching device 84 and the power transmission direction switching switch 76 of the phase determination circuit 2 can be driven. With the switching device 84 and the switch 76, the power transmission direction of the accident detection device can be automatically switched in response to the distribution line switching operation for frequent load flow adjustment, and the direction of the ground fault accident can be determined. can do. Further, the fact that an accident has occurred can also be displayed by the switching device (display 84).

The effect of the present invention has been described above based on the embodiment.However, as seen in the embodiment, according to the present invention, an extremely significant accident of a distribution line is detected, the accident state is displayed, and
It was possible to provide an accident detection device (circuit) capable of sending a control signal.

[Brief description of drawings]

FIG. 1 is a circuit system diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of a phase determination circuit used in the present invention,
FIG. 3 is a circuit diagram of a main circuit showing another embodiment of the present invention. 1 …… Sensor section 1A, 1B, 1C …… Sensor 2 …… Intermediate connection section 3 …… Phase determination circuit 4,5,6 …… Current transformer 7,8,9,10,11,12 …… Capacitor 13 …… Grounding 14,15 …… Diode (anti-parallel connection diode) 16,17 …… 〃 〃 18,19 …… 〃 〃 34,35 …… 〃 〃 38,39,40 …… Primary transformer winding 48… … Transformer tertiary winding 49,50,51 …… Transformer secondary winding 63,64 …… Amplifier 76 …… Direction switch 77 …… Phase comparison circuit 84 …… Transmission direction discrimination switching device (display) R , S, T …… Distribution line (phase) N ₁ , N ₂ …… Neutral line R ₂₉ , R ₃₀ , R ₃₁ …… Load resistance R ₃₂ …… Small current detection resistance R ₃₃ …… Current combined resistance

Claims (6)

[Claims] Claim: What is claimed is: 1. A distribution line accident detection device capable of detecting an accident in a polyphase distribution line, determining the direction of the accident, and automatically switching the power transmission direction. And a sensor unit having a current transformer that detects the voltage, and a capacitor-type transformer that is connected between each phase of the distribution line and the ground to detect the voltage of each phase,
A resistor connected between the secondary terminals of each of the current transformers (hereinafter referred to as load resistance), and a resistor connected to a system in which currents flowing through these load resistors are combined (hereinafter referred to as current combined resistance),
A resistor connected in series with the load resistor connected between the secondary winding terminals of one of the plurality of current transformers and having a resistance value larger than the resistance value of the load resistor. (Hereinafter referred to as a minute current detection resistor), and at least between the terminals of each of the load resistors, between the terminals of the current combination resistor, and the minute current input through the intermediate connection portion. A distribution line accident detection device, comprising: a phase determination circuit that determines an accident direction based on an input signal including a detection signal between terminals of a detection resistor and enables automatic switching of a power transmission direction. 2. A distribution line accident detection device capable of detecting an accident in a multi-phase distribution line, determining the direction of the accident, and automatically switching the transmission direction, and connecting each phase of the distribution line with the current of each phase. And a sensor unit having a current transformer that detects the voltage, and a capacitor-type transformer that is connected between each phase of the distribution line and the ground to detect the voltage of each phase,
A load resistor connected between the secondary terminals of each of the current transformers, a current combining resistor connected to a system in which currents flowing through the load resistors are combined, and one of the plurality of current transformers. A current transformer in which the primary winding is connected in series to the load resistance connected between the secondary winding terminals of the current transformer and the terminal of the secondary winding is connected to the system (hereinafter referred to as a small current detection current transformer). )When,
An intermediate connection part having a minute current detection resistor connected between the secondary winding terminals of the minute current detection current transformer, and at least each of the load resistors input via the intermediate connection part. And a phase determination circuit capable of automatically switching the power transmission direction based on an input signal including a detection signal between the terminals of, the terminals of the current synthesis resistance and the terminals of the minute current detection resistance. A distribution line accident detection device characterized in that 3. The distribution line fault detecting device according to claim 1 or 2, wherein an anti-parallel connection diode is connected in parallel to the minute current detection resistor. 4. The intermediate connection section includes a transformer connected to each of the capacitor type transformers, and the zero phase voltage of the polyphase distribution line is sent to the phase determination circuit via the secondary windings of these transformers. The distribution line accident detection device according to claim 1, 2, or 3, characterized in that it is formed. 5. The induced voltage is sent to a phase determination circuit via a tertiary winding that is electromagnetically coupled to the primary winding of one of the transformers in the intermediate connection section so as to form a phase voltage. The distribution line accident detection device according to claim 4, characterized in that 6. A phase determination circuit, a phase comparator for comparing the phases of input signals from the intermediate connection section, a power transmission direction determination switching device driven by the phase comparator, and automatic switching by the operation of the power transmission direction determination switching device. The distribution line accident detection device according to any one of claims 1 to 5, further comprising a power transmission direction changeover switch that operates.