JP2001320828A - Ground relay with failed-area determining function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To delay the operating time of a ground relay on the non-utility side in case of an accident-incurred by providing a means of determining whether an earth fault, if it occurs in non-utility power receiving equipment connected to a high-tension distribution line from a distribution substation, occurs on the non-utility side or not. SOLUTION: A controlling device 10 disposed in the ground relay on the non-utility side is so formed that, using the information of failed current obtained by detecting an input signal in a residual current transformer on the non-utility side, a signal of the failed current may be transmitted from an input circuit 12 to a filter circuit 13 and then a higher harmonic analysis circuit 14 and a level detection circuit 15, outputs from the former two circuits may be inputted, with a signal of a timer 17, into an operating time characteristics switching circuit 16 for processing, and a signal may be outputted into an operation circuit of the GR through an output circuit 18. Two pieces of information of waveform difference and analytic value of higher harmonies are used for determination and, in case of an accident-incurred, such a control as delays operating time of the GR is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground fault relay connected to a transmission / distribution facility of a high-voltage electrical facility and provided to a private electrical facility, and determines whether or not a place where a ground fault has occurred is on a private side. The present invention relates to a device for protecting a private-use ground fault relay from operating when an accident occurs in a power system.

[0002]

2. Description of the Related Art In general, in a power transmission and distribution facility including a high-voltage electrical facility, private power receiving facilities 3, 4 are connected to a high-voltage distribution line 2 from a supply substation (distribution substation) 1 as shown in FIG.
Are provided, and a power supply path for supplying power to each demand unit is provided in the private power receiving equipment 3, 4,.... In a general factory or the like, a high-voltage distribution line from a distribution substation is branched and connected to a private power receiving facility, and low-voltage power is supplied to a private electric facility such as a motor through a transformer. In the private power receiving equipment, a ground fault relay for high-voltage power receiving (hereinafter referred to as "GR") is widely used. When a ground fault occurs in the private equipment, the GR operates to open and close the private equipment side. The vessel is cut off and disconnected from the high voltage power distribution line.

[0003]

However, since the GR provided in the private power receiving equipment also operates in the event of an accident on the high-voltage distribution line (received accident), the GR is used when there is no abnormality in the private power receiving equipment. Also has the problem of power outages. When an abnormal current flows on the high-voltage distribution line side, even if power transmission is restarted after a relatively short-time (several seconds) power failure, the state in which the switch is turned off continues on the private side. A long time is required for recovery, and a large loss occurs due to a power outage in factories and the like. In addition, a static device is generally used as the GR, and it is necessary to provide a power supply externally supplied or a control power supply by a dedicated transformer in an AC load switch with GR.
However, when performing GR control using a dedicated power supply, it is necessary to provide an extra power supply system, and when a dedicated transformer is used, there is a problem that the entire switch becomes large.

[0004] The present invention is intended to eliminate the unnecessary operation of the conventional GR as described above, and does not operate for a received accident, but for other equipment for its own ground fault. It is a first object of the present invention to provide a device capable of operating a switch at an early stage so as not to affect power, and to provide a means capable of easily supplying control power to a GR.
The purpose is.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a private high-voltage power receiving facility connected to a high-voltage distribution line from a distribution substation. In the invention of claim 1 of the present invention, a switch incorporating a zero-phase current transformer is arranged in the private high-voltage power receiving equipment, and a ground fault relay is arranged via the zero-phase current transformer, and provided in the switch. The ground fault relay is provided with means for discriminating between an accident on the private high-voltage power receiving facility side and an accident on the high-voltage distribution line side from zero-phase current data of the high-voltage path input from the zero-phase current transformer. When the generation source is on the high-voltage distribution line side, the operation time of the switch on the private high-voltage power receiving equipment side is controlled to be delayed.

According to a second aspect of the present invention, in the accident determining means provided in the private high-voltage power receiving facility, an accident on the high-voltage distribution line side is determined based on a result of analyzing a waveform of the fault current. It is characterized in that control for delaying the operation time of the switch of the equipment by a predetermined time from the operation time at the time of the accident at the private high-voltage power receiving equipment side is performed. Claim 3
In the accident determination means provided in the private high-voltage power receiving equipment, the information input from the zero-phase current transformer to the control circuit of the ground fault relay is input in parallel to a harmonic analysis circuit and a level detection circuit. Transmitting the outputs of the two circuits to an operating time characteristic switching circuit, wherein the operating time characteristic switching circuit compares the distortion rate of the waveform and the content of even harmonic components with a preset value, It is characterized in that a means for determining whether or not it is for private use is provided.

[0007] Since the control device configured as described above is used, when an abnormal current flows, it is possible to easily determine whether a ground fault has occurred on the private side or a fault has been received. If the fault is not a ground fault on the private side, while the operation of the switch is delayed, the electric circuit on the side on which the fault current flows is interrupted, and the switching on the specific private side is performed. The vessel will not have to be shut off. Therefore, by the control device, as in the case of the conventional GR,
When it is detected that an abnormal current has flown, the process of shutting off the switch is not performed immediately, so that unnecessary cutoff of the switch is reduced, and the frequency of performing the recovery process after a power failure is reduced.
Further, a ground fault on a specific private side does not affect power receiving facilities and substations on other private sides.

A fourth aspect of the present invention is a private high-voltage electrical facility connected to a high-voltage distribution line from a distribution substation.
For a ground fault relay provided in the private high-voltage power receiving equipment,
A self-power supply circuit as a control power supply is provided, and in the self-power supply circuit, a current transformer is configured by arranging a magnetic core provided with a secondary winding with respect to an insulating bushing used for insulating a primary conductor. And

A power supply required for the operation of the GR is provided by means for supplying a current flowing through the high-voltage capacitor and the load equipment through a self-power supply circuit, so that a power supply such as a conventional GR can be separated. It is not necessary to form using a transformer or the like. In the self-power supply circuit, since the through bushing is used, it is not necessary to insulate the magnetic core and the secondary winding of the current transformer from the primary conductor, and no imbalance occurs in the surging impedance of the high-voltage path. Therefore, there is a feature that the concentration of the transient voltage hardly occurs on the high piezoelectric path.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of operation of the device of the present invention and the background art will be described. Generally, as shown in FIG. 8, a GR accident involves an accident in a high-voltage distribution line when a large number of private power receiving facilities are connected to the high-voltage distribution line from the distribution substation. And accidents at other private power receiving facilities. Then, the GR of each private power receiving facility connected to the high-voltage distribution line detects an abnormal current flowing due to the accident and performs an operation of disconnecting from the high-voltage distribution line.

The current flowing in the event of the accident described above is shown in FIG.
As shown in the equivalent circuit diagram of the ungrounded distribution system at the time of the ground fault on the distribution line 2, a zero-phase voltage Vo is generated in the distribution system. The current Ig2 flows through the private-use-side ground capacitance C2 due to Vo generated in this system. The state in which the current Ig2 flows is called an accident. In this equivalent circuit diagram, R: equivalent neutral point resistance for distribution substation, Vo: zero-phase voltage, E: distribution line-to-ground voltage, Rg: ground-fault point resistance, C1 · C
2: Capacitance to ground on distribution line side and private side, ZCT1:
Distribution substation zero-phase current transformer, ZCT2: private-use zero-phase current transformer.

* Operation of receiving accident: For example, in FIG. 8, when a ground fault occurs in the private electric equipment 3, it is desirable that only the GR of the electric equipment 3 operates and is disconnected from the distribution line 2. However, when a ground fault occurs in the facility 3, the current Ig2 flowing at that time causes the GR to operate in other facilities 4 and the like, resulting in an unnecessary power failure. In other words, the accident of the facility 3 also affects other facilities 4 and the like, causing an influence to occur outside the protection range of the facility 3 where the ground fault has occurred. * The magnitude of the current of the fault accident: The magnitude of the fault current Ig2 [A] is the zero-phase voltage Vo [V] generated by the ground fault of the system, the private-use side ground capacitance C2 [F], and Equation 1 defines the frequency f [Hz] of the system. Ig2 = 2πfC2Vo Equation 1 * Operation of ground fault relay (GR) for high-voltage power receiving: GR is a rated frequency (commercial frequency) current (hereinafter referred to as “commercial frequency”) flowing at a zero-phase current transformer (hereinafter “ZCT”) installation point. Ig ”) and operates only by determining the size of the relay. The GR for high-voltage power receiving equipment is generally a stationary type and has an operating current tap (0.2 A,
0.4A), and the operation time is a fixed time operation (operates in a fixed time when Ig exceeds a certain value from the tap value) as in the example of FIG. Further, Ig and zero-phase current I
The relationship of o is represented by Ig = 3Io.

* Unnecessary operation of GR due to accidents received: A number of high-voltage power receiving facilities 3, 4, ... connected to the high-voltage distribution system
When a ground fault occurs in one of the above, Vo is generated in the high-voltage distribution system as shown in the equivalent circuit diagram of FIG.
Due to this Vo, a fault current Ig2 received from ZCT2 according to the ground capacitance of each private electric facility flows. The magnitude of the Ig2 is the magnitude shown in the above equation 1. The magnitude of the received fault current is determined by the settling tap value of GR (0.
2A, 0.4A, etc.) and the current continuously exceeds the sum of the inertial inactivity time and the margin time as shown in FIG. 4, the GR operates to cut off the electric circuit. The magnitude of Ig2 is proportional to the ground capacitance C2 of the private electric equipment when Vo is constant. Accordingly, the unnecessary operation of the GR becomes easier as the electrical equipment has a larger ground capacitance (the longer the high voltage cable length). From these points,
If a ground fault occurs in one of many private electrical facilities connected to the same distribution system, the electrical equipment with a large capacitance to ground will receive the GR and unnecessary operation will occur due to the fault current. However, there is a problem that the private electrical equipment of the company leads to unnecessary power outages.

Characteristics at the time of ground fault at the private side: ground fault current waveform and harmonic component analysis example: At the time of ground fault at the private side, a ground fault current Ig as shown in the equivalent circuit diagram of FIG. 9 flows. An example of the Ig waveform is as shown in FIG. 10, and an example of the harmonic component analysis is as shown in FIG. The characteristics of the waveform and harmonic components are as follows. (A) Since the ground fault current waveform is often caused by discharge, as shown in FIG. 10, the fundamental wave component is small and the harmonic component is large. (B) When an intermittent discharge or the like occurs, a large number of so-called asymmetric waves, in which the waveforms on the positive electrode side and the negative electrode side are asymmetric, are generated. (C) When an asymmetric wave is generated, the harmonic components include many even-order harmonic components such as the second and fourth harmonics as shown in FIG. (D) In the case of an oil-filled device such as a transformer, since the arc extinguishing ability of the insulating oil is high, high-order harmonics are generated with random discharge.

Features of ground fault current value change at private ground fault: The equivalent circuit at the private ground fault is as shown in FIG. 9, and the current Ig2 'flowing through ZCT2 is a composite current as shown in FIG. , The second expression.

Calculation Example 1 (when the ground fault point resistance is Rg) Equation 2 However, 2πf = ω Calculation example 2 (complete ground fault, ground fault resistance Rg is “0”) Rg2 ′ = ｛(1 / R) + jωC1ωE (3) From the above equations (2) and (3), Rg2 ′ is , The earth capacitance C1 of the system, the equivalent neutral point resistance R of the substation, the earth voltage E and the ground fault resistance Rg. In general, the value of the current flowing at the time of a private ground fault is large as compared with the fault current received because the value of C1 is as large as several μF to several tens μF, and changes from 0 (Rg = ∞) due to the change of the ground fault point resistance. , To several tens A (Rg = 0). Further, the ground fault resistance often develops into an arc ground fault, and may change from a small current region to a maximum value in a very short time due to the characteristics of the arc. Note that the maximum current is substantially determined by the ground capacitance C1 of the system, and is often about 10 to 30 A.

Features at the time of the accident: If a ground fault occurs as shown in the equivalent circuit diagram of FIG.
An example of an Ig waveform at the CT installation point is as shown in FIG. 13, and an example of the result of the harmonic component analysis of the Ig is obtained as shown in FIG. * Ground fault current waveform and harmonic component analysis: The fault current received is G
The case where the tap value of R is close to the tap value (0.2 A, 0.4 A, etc.) is a case where the distribution system is close to a complete ground fault. The characteristics of the waveform and harmonic components at this time are as follows. (A) The ground fault current waveform hardly contains harmonic components and has many fundamental wave components. (B) Many symmetric waves are generated in which the positive and negative sides of the waveform are symmetric. (C) The harmonic component has many odd-numbered wave components and hardly contains even-numbered wave components.

* Characteristics of Ig change at the time of accident: The current flowing from the equivalent circuit of FIG. 12 to ZCT2 is determined by the ground capacitance C2 of the private electric equipment and Vo, and becomes the current value of the above equation (1). . In the 6,6 kV system, V
Since o is 3810 V at the maximum and the capacitance C2 is generally 1/10 or less as compared with C1, the current of the accident to be received is generally 1A or less. When the maximum value of Vo is Vom, the maximum current Ig2m is expressed by the following equation 4. Ig2m = 2πfC2Vom Equation 4 Therefore, when C2 is measured in advance, the maximum current value Ig2m is known, and the value of Ig2 is Ig2
converge to m.

Means for Preventing GR Operation Due to Receiving Fault Current * Principle: As in the above example, the ground fault current waveform flowing to the private equipment ZCT installation point is the same as the fault on the private side ground fault. There is a remarkable difference in the fault current waveform. Also, at the time of a complete ground fault on the private side and the Ig of the ZCT2
The size has a difference of 10 times or more. By utilizing this property, when it is determined that an accident is caused by a private side ground fault or when an accident is determined, the operation time characteristic of the relay is changed, and unnecessary operation of the relay due to the received fault current is reduced. .

* Operation time characteristics of distribution substation: The ground fault protection operation of the distribution substation operates under the AND condition of a ground fault directional relay (DGR) and a ground fault overvoltage relay (OVG). If a ground fault occurs, the operation is set to perform a timed operation within 1 second (generally about 0.7 seconds).

* Important points on the operating characteristics of the relay: When designing or setting a protection relay for private facilities, set the operating time of the relay device so that the private side is earlier than the distribution substation. Then, when there is a ground fault on the private side, the private side ground fault relay is immediately operated to eliminate the accident and prevent the relay device of the distribution substation from operating first.

* Differences between accidents caused by ground faults on the private side: The protection range discriminating function provides a ground fault current waveform of ZCT primary current and a ground fault current value for each of the faults caused by the ground fault on the private side. Attention is paid to the difference in the change, and at the time of the private side ground fault, the accidents caused by the ground fault of the power distribution system are determined. If the ground fault is determined to be a private side ground fault, the GR is operated to quickly shut off the switch. If it is determined that the accident has occurred, the operating time characteristic of the GR is changed to
Control is performed to prevent unnecessary operation of R. As described above, in the present invention, it is assumed that there is a clear difference between the waveform and the magnitude of the current between the case of the accident and the case of the accident on the private side. An apparatus as described can be configured.

Next, the configuration of the device of the present invention utilizing the above-described operation principle will be described. In the control device 10 shown in FIG. 1, information of a fault current detected by a private zero-phase current transformer (hereinafter referred to as “ZCT”) is used as an input signal, and the fault current signal is input from an input terminal 11 to an input circuit. Input to 12. The output of the input circuit 12 is transmitted to the filter circuit 13,
The output is transmitted to the harmonic analysis circuit 14 and the level detection circuit 15. The outputs of the harmonic analysis circuit and the level detection circuit are transmitted to an operation time characteristic switching circuit 16 for processing.
Is also input and processed, and the signal is output to the GR trip circuit via the output circuit 18.

In each circuit arranged in the control device 10, the input circuit 12 converts a secondary current input from the ZCT secondary terminal into a voltage which can be easily processed inside the GR.
The filter circuit 13 is a low-pass filter, and can pass a frequency band from a system frequency to a frequency component of a needle waveform.

The harmonic analysis circuit 14 performs a harmonic analysis on the Ig waveform, and when the waveform distortion rate (effective value of the harmonic component / effective value of the fundamental wave) exceeds a certain ratio, or an even harmonic. When the content of the wave component (the effective value of the even wave component / the effective value of the waveform) exceeds a certain ratio, a signal determined to be a private side is output to the operation time characteristic switching circuit 16. If the waveform distortion or the content of the even harmonic components is equal to or less than a certain ratio, a signal for determining a fault current to be received is output to the operation time characteristic switching circuit 16. The level detection circuit 15 detects the magnitude of the input Ig current as an effective value or an average value, and outputs a signal to the operation time characteristic switching circuit 16.

The operating time characteristic of the operating time characteristic switching circuit 16 is expressed by two characteristics, ie, a fixed time characteristic and an inverse time characteristic (the operating time becomes shorter as Ig becomes larger).
The switching process is performed according to the result of the harmonic analysis of the waveform. (A) Periodic operation: When a ground fault occurs in a private facility, since the Ig is large, the operation time is shortened, and it is necessary to eliminate the ground fault accident promptly. Therefore, as in the case of the conventional GR, the operating time characteristic switching circuit 16
When it is determined by the harmonic analysis that the ground fault is for the private use, the operation is performed in a fixed-time operation characteristic shown in FIG. 2. To work. In addition, when it is determined that the private ground fault occurs, the time for operating the GR is set to about 0.2 seconds.

(B) During the time limit operation: As a result of the harmonic analysis,
If it is determined that the accident has occurred, it is processed as the time limit characteristic shown in FIG. In other words, when a ground fault occurs in another private facility connected to the distribution system, the fault current (Ig) of the fault is small, so the operating time is longer than the operating time of a general GR. Unnecessary GR operation is prevented by using a time limit characteristic that causes a delay. The timer circuit 17 outputs a signal for a fixed time, and is used for setting the operation time in FIGS. The output circuit 18 outputs an operation signal (trip signal or the like) to the GR.
Is output to GR.

In the control device 10 configured as described above, the waveform analysis as shown in FIGS. 10 and 13 is performed in the harmonic analysis circuit 14, and the level detection circuit 15 performs the analysis as shown in FIGS. The analysis is performed, and information on the result of the analysis is transmitted to the operation time characteristic switching circuit 16. The operation time characteristic switching circuit 16 determines a ground fault at the private power receiving equipment connected to the GR and a received accident, and the level detection circuit 15 detects the magnitude of the current from the Ig waveform. A few input currents (Ig)
Used as data for

When it is determined that a ground fault has occurred in the private facility based on the information input to the operation time characteristic switching circuit 16, the operation of shutting off the switch is quickly performed, and the distribution substation is operated. And do not affect other private facilities connected to the distribution line. If the detected current is determined to be an accident, the signal processing is performed by taking into account the signal of the timer 17, a margin time is set as shown in FIG. By performing the process of delaying the operation time of the switch of
The switch at the private power receiving equipment where R is installed is not interrupted.

By providing the control device 10 having the above-described configuration, when an abnormal current flows, it is possible to easily determine whether a ground fault has occurred on the private side or an accident has been received. If the fault is not a ground fault on the private side, while the operation of the switch is delayed, the electric circuit on the side on which the fault current flows is interrupted, and the switching on the specific private side is performed. The vessel will not have to be shut off. Therefore, when the control device detects that an abnormal current has flowed as in the case of the conventional GR, it does not immediately perform the process of shutting off the switch, so that unnecessary shutoff of the switch is reduced, and recovery is reduced. Work is performed less frequently. Further, a ground fault on a specific private side does not affect power receiving facilities and substations on other private sides.

[0031]

[GR Power Supply] In general, a conventional AC load switch includes a dedicated transformer, and a transformer is arranged on the load side of a switch provided between the high-voltage path and the load side.
To a low-voltage AC low-voltage power supply, and supplies a power supply voltage of about 110 V to the GR. However, in the case of the power supply device using the dedicated transformer, there is a problem that the GR operation cannot be performed normally when an abnormality occurs in the secondary wiring of the transformer. When an external power supply is wired as a power supply for the GR, it is necessary to provide a circuit dedicated to the GR power supply in an electric room or the like and to perform wiring of the power supply.
There is a problem with the wiring and maintenance of the dedicated line.

Therefore, in order to cope with the problem of power supply to the GR, for example, as shown in FIG. A power supply circuit 30 can be provided. The self-power supply circuit 30 includes a primary conductor 2 on a metal part of an outer case of the switch.
1 is disposed at a portion through which the primary conductor 21 passes, and a magnetic core 23 provided with a secondary winding 24 is disposed with respect to an insulator through bushing 22 used for insulating the primary conductor 21. A current corresponding to the winding ratio of the next winding 24 is supplied to the self-power supply circuit 30. BCT20 is when the primary conductor 21 is the primary current I ₁ flows, to flow the secondary current I ₂ corresponding to the current transformer ratio in the secondary winding, self-powered circuit 3 this current
By supplying to 0, it becomes possible to configure a self-powered AC load switch with GR without an external power supply.

In order to provide the self-power function to the GR,
The characteristics of the private high-voltage power receiving equipment as shown in FIG. 6 can be used. In the high-voltage power receiving equipment, the switch 2
The current I ₁ flowing through the installation location of the reference numeral 5 is the vector sum of the current Ic flowing through the high-voltage advance capacitor 27 and the current IL flowing through the load 26. The load current always fluctuates, and fluctuates from 0 to the maximum value. However, even if the load current IL becomes 0, a constant current always flows through the capacitor 27. It can be used as a power source for the GR by utilizing the fact that the power does not change.

As described above, in order to utilize the current that always flows through the primary conductor of the switch 25, a self-power supply circuit as shown in FIG. 7 can be constructed. In the example shown in FIG. 7, the secondary current of the self-power supply circuit obtained by the BCT (the same member as the BCT 20 of FIG. 5) is boosted to a required voltage by the boosting transformer 32 of the self-power supply circuit 30. The output voltage of the transformer 32 is rectified and stabilized by the rectifying / stabilizing circuit 3.
Rectify and stabilize through 3. Used as a DC power supply required for GR operation. Since a necessary power supply may not be obtained in an initial stage of use of the apparatus, a battery 34 is provided and used as a power supply for the ground fault detection unit 35. In addition,
As the battery, a secondary battery such as a nickel-metal hydride battery or an ultra-large capacity capacitor (super capacitor) can be used.

Therefore, by using the power supply required for the operation of the GR through the current flowing through the primary conductor of the switch 25 through the BCT 20, the power supply is converted to another transformer as in the conventional GR. It is not necessary to form using a container or the like. In the self-power supply circuit, since the through bushing is used, it is not necessary to insulate the magnetic core and the secondary winding of the current transformer from the primary conductor, and no imbalance occurs in the surging impedance of the high-voltage path. Therefore, there is a feature that the concentration of the transient voltage hardly occurs on the high piezoelectric path. Also,
By using the BCT, the transition voltage value from the primary conductor to the secondary side is generally small. Further, the secondary current is
It can also be used for detecting overcurrent of a switch.

[0036]

The device of the present invention uses the control device configured as described above. Therefore, when an abnormal current flows, it is easy to determine whether a short-circuit accident has occurred on the private side or an accident has occurred. Can be. If the fault is not a ground fault on the private side, while the operation of the switch is delayed, the electric circuit on the side on which the fault current flows is interrupted, and the switching on the specific private side is performed. The vessel will not have to be shut off. Therefore, the conventional GR
As in the case of (1), when it is detected that an abnormal current has flowed, the process of shutting off the switch is not performed immediately, so that unnecessary shutoff of the switch is reduced, and the frequency of the recovery process after a power failure is reduced. . Further, a ground fault on a specific private side does not affect power receiving facilities and substations on other private sides.

Further, in the present invention, a power supply required for the operation of the GR is provided with means for supplying a current flowing through the primary conductor of the high-voltage path through the BCT, thereby providing a power supply similar to the conventional GR. In addition, there is no need to form the power supply using another transformer or the like. In the self-power supply circuit, since the through bushing is used, it is not necessary to insulate the magnetic core and the secondary winding of the current transformer from the primary conductor, and no imbalance occurs in the surging impedance of the high-voltage path. Therefore, there is a feature that the concentration of the transient voltage hardly occurs on the high piezoelectric path. Further, by using the self-power supply circuit, a transition voltage value from the primary conductor side to the secondary side is generally small, and the secondary side current can be used also for overcurrent detection of a switch.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a control device of the present invention.

FIG. 2 is an explanatory diagram of a relationship between an operation time and an input current in a timed operation.

FIG. 3 is an explanatory diagram of a relationship between an operation time and an input current in a time limit operation.

FIG. 4 is an explanatory diagram of an operation time.

FIG. 5 is an explanatory diagram showing a configuration of a BCT.

FIG. 6 is an explanatory diagram of a private high-voltage power receiving facility.

FIG. 7 is an explanatory diagram showing a configuration of a self-power supply circuit.

FIG. 8 is an explanatory diagram of a current flowing in a power distribution system for an accident.

FIG. 9 is an explanatory diagram of a current flowing in a private accident.

FIG. 10 is an explanatory diagram of a waveform of a fault current.

FIG. 11 is an explanatory diagram of the waveform analysis of FIG. 10;

FIG. 12 is an explanatory diagram of a current flowing in a received accident.

FIG. 13 is an explanatory diagram of a waveform of a fault current.

14 is an explanatory diagram of the waveform analysis of FIG.

[Explanation of symbols]

1 Substation, 2 Distribution line, 3/4 Private electrical equipment, 10 Control device, 11 Input terminal, 1
2 input circuit, 13 filter circuit, 14 harmonic analysis circuit, 15 level detection circuit, 16 operating time characteristic switching circuit, 17 timer, 18 output circuit, 20 BCT, 21 primary conductor, 22
Piercing type bushing, 23 magnetic core, 24 secondary winding, 25 switch, 26 load, 27 high-voltage advance capacitor, 30 self-power supply circuit, 31
BCT, 32 step-up transformer, 33 rectification / stabilization circuit, 34 battery, 35 ground fault detector.

Claims (4)

[Claims] 1. A private high-voltage power receiving facility connected to a high-voltage distribution line from a distribution substation, wherein a switch incorporating a zero-phase current transformer is disposed in the private high-voltage power receiving facility, and the zero-phase current transformer is provided. A ground fault relay is arranged via the ground fault relay provided in the switch, based on the zero-phase current data of the high-voltage path input from the zero-phase current transformer, the accident on the private high-voltage power receiving equipment side and the high-voltage distribution line. Means for discriminating an accident on the side of the accident, wherein when the source of the accident is on the high-voltage distribution line side, control is performed to delay the operation time of the switch on the side of the private high-voltage power receiving facility. Ground fault relay with discrimination function 2. An accident discriminating means provided in the private high-voltage power receiving facility, based on a result of analyzing a waveform of the fault current, discriminates an accident on the high-voltage distribution line side, and determines whether or not the switch of the private high-voltage power receiving facility has a switch. The ground fault relay with an accident area discrimination function according to claim 1, wherein control is performed to delay the operation time by a predetermined time from the operation time at the time of the accident at the side of the private high-voltage power receiving facility. 3. An accident discriminating means provided in the private high-voltage power receiving equipment, wherein information inputted from a zero-phase current transformer to a control circuit of a ground fault relay is inputted in parallel to a harmonic analysis circuit and a level detection circuit. The outputs of the two circuits are transmitted to an operation time characteristic switching circuit. In the operation time characteristic switching circuit, the distortion rate of the waveform and the content of the even harmonic component are compared with preset values. 3. The ground fault relay with an accident area discriminating function according to claim 2, further comprising means for judging whether or not it is a private use side. 4. A private high-voltage electrical facility connected to a high-voltage distribution line from a distribution substation, wherein a ground fault relay provided in the private high-voltage power receiving facility is:
A self-power supply circuit as a control power supply is provided, and in the self-power supply circuit, a current transformer is configured by arranging a magnetic core provided with a secondary winding with respect to an insulating bushing used for insulating a primary conductor. A ground fault relay with an accident area discrimination function, which is provided with a self-powered type that does not have a power supply.