JPH02275373A - Fault direction discriminator for overhead distribution wire - Google Patents

Abstract

PURPOSE:To enable quick discovery of a fault point by detecting a phase voltage, a phase current, a zero phase voltage and a zero phase current of an overhead distribution wire to discriminate directions of power transmission, ground fault and short circuiting. CONSTITUTION:Coupling capacitors PD1-PD3 detect a normal phase voltage to generate a phase voltage signal and a zero-phase voltage signal through a voltage signal processing circuit 12. On the other hand, current transformers 11R, 11S and 11T detect a normal phase current and a current transformer 13 detects a zero phase current. As a result, a transmission direction discriminator circuit 14 discriminates a direction of transmission based on a phase difference between a phase voltage and a phase current. A ground fault detection circuit 15 detects a ground fault based on a zero-phase voltage and the zero-phase current. Moreover, a short circuiting detection circuit 16 detects a short- circuiting based on a current value of the total phase current. Then, when a fault is determined to occur on the side of a load through a phase inversion circuit 17 and a phase comparator circuit 18, a display lamp is made to flash. This clarifies direction of a fault, thereby achieving a quick recovery work.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fault direction determination device in an overhead power distribution line.
In particular, the present invention relates to a fault direction determination device for an overhead power distribution line that constantly monitors the power transmission direction and displays a ground fault or short circuit fault when it occurs on the load side to facilitate finding the fault point.

[Background technology]

As a recent trend, high-voltage distribution lines are being coated as part of efforts to improve the reliability of power distribution equipment, and this has greatly contributed to the reduction of power line-related accidents.

However, when two or more wires are flashed near the insulator due to a lightning strike, it progresses to a different-phase ground fault, and as a result, coated insulated wires are more likely to break than bare wires, and even breakage can occur. The duration of the accident is short, and the disconnection causes the conductor to dig into the insulator at the disconnected surface. Therefore, even if a broken distribution line falls to the ground, the substation protection relay may not be expected to operate, and even if it operates, there are cases where power is successfully retransmitted.

In order to prevent this, in recent years, distribution line relays with different phase ground fault detection have been installed at substation distribution line outlets. Measures were taken to stop the re-closing, and during this time the broken line was discovered6, power was immediately transmitted to the healthy section, and repair work was carried out.

[Problem to be solved by the invention]

However, the method described above has a problem in that it takes a considerable amount of time to discover the accident point.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an apparatus for determining the direction of a fault in an overhead power distribution line, which can quickly find the point of a fault.

[Means for Solving the Problem] In order to achieve the above-mentioned object, the present invention detects the phase voltage and phase current of an overhead distribution line by a first detection means,
Determining the power transmission direction of the overhead distribution line based on the phase difference between the phase voltage and the phase current of at least one phase, and detecting the zero-sequence current and zero-sequence voltage of the overhead distribution line by a second detection means, Ground faults are detected based on the voltage value of this zero-sequence voltage and current value of the zero-sequence current, while short-circuit accidents in overhead distribution lines are detected based on the phase current input of all phases, and the power transmission direction and The direction of the ground fault is determined based on the phase difference between the zero-sequence voltage and zero-sequence current, and when the direction of the ground fault is on the load side,
Another object of the present invention is to provide a fault direction determination device for an overhead power distribution line that displays a predetermined display when a short circuit fault is detected.

That is, the fault direction determination device for an overhead power distribution line according to the present invention includes the following means.

(1) The first detection means detects the phase voltage and phase current of the overhead distribution line. For example, the phase voltage can be detected by attaching a coupling capacitor etc. to the overhead distribution line. Current detection can be accomplished by coupling a current transformer or the like to an overhead power distribution line to generate a phase current signal.

(2) Second detection means detects the zero-sequence current and zero-sequence voltage of the overhead distribution line, for example, as a means for detecting the zero-sequence current, a current transformer that detects the phase current of each phase; It can be configured by a synthesis means for synthesizing the phase current signals generated from the current transformer, and a coupling capacitor for detecting the phase voltage of each phase and an output from the coupling capacitor as a means for detecting the zero-sequence voltage. It can be configured by a combining means that combines the phase voltage signals.

(3) Power transmission direction determination means determines the power transmission direction of the overhead power distribution line based on the phase difference between the phase voltage and phase current of at least one phase. This means that, for example, the phase difference θ between the phase voltage and the phase current is -70e to 1
10'', that is, within the range of 70 degrees of delay to 110' of advance, the power transmission direction of the overhead power distribution line is determined to be progressive;
If it is within the range of 90', the power transmission direction of the overhead power distribution line is determined to be reverse transmission.

(4) Ground fault detection means A ground fault is detected based on the voltage value of the zero-sequence voltage and the current value of the zero-sequence current. For example, in the case of a 6KV distribution line, the level of the zero-sequence current is When the level of the zero-sequence voltage reaches 100 mA and 380 V, it is determined that a ground fault has occurred.

(5) Short-circuit accident detection means Detects the phase current level of all phases and detects short-circuit accidents in overhead distribution lines based on this. For example, in low-load distribution areas, when it reaches 300A, In heavy load areas, it is determined that a short circuit has occurred when the voltage reaches 600A.

(6) Ground fault direction determination means When a ground fault is detected by the above-mentioned ground fault detection means, the direction of the ground fault is determined based on the power transmission direction and the phase difference between the zero-sequence voltage and zero-sequence current. It is something to do. That is, for example, when the power transmission direction of the overhead power distribution line is progressive, the phase difference θ between the zero-sequence voltage and the zero-sequence current is within the range of -45° to 135°, that is, from lag 45° to lead 135°. If it is determined that there is an accident on the load side, and if the angle is between 135° and 315″
That is, if it is within the range of advance 135° to advance 315°, it is determined that there is an accident on the power supply side. Additionally, when the power transmission direction is reverse, the zero-sequence current is reversed by an inverter, etc., and the determination is made based on the phase difference θ between the reversed zero-sequence current and zero-sequence voltage in the same way as in the case of forward transmission. There is.

(7) Display means When the direction of the ground fault fault is determined to be the load side by the above-mentioned fault direction detection means, or when a short circuit fault is detected by the short circuit fault detection means, a predetermined display is performed, for example. , lamps, LEDs, and other indicator lights are turned on and blinking. It should be noted that since short circuits can be detected only when they occur on the negative and thin sides, short circuits that occur on the power supply side cannot be detected.

[Effect]

In the above configuration, a short circuit fault is detected based on the level of the phase current detected by the first detection means, and a short circuit fault is detected based on the level of the zero-sequence current and zero-sequence voltage detected by the second detection means. While detecting a fault, the power transmission direction determining means constantly monitors and determines the power transmission direction of the overhead power distribution line based on the phase difference between the phase current and the phase voltage. When a ground fault is detected by the ground fault detection means, the direction of the ground fault is determined based on the power transmission direction and the phase difference between the zero-sequence voltage and the zero-sequence current. or when the short circuit accident detecting means detects a short circuit accident, the display means makes a predetermined display. Therefore, the presence or absence of an accident and its direction are made clear, and the accident point can be quickly discovered, thereby allowing recovery work to be carried out quickly.

〔Example〕

Hereinafter, the fault direction determination device for an overhead power distribution line according to the present invention will be described in detail.

FIG. 1 shows a first embodiment of the present invention, in which three of R, S, and T are shown.
A phase distribution line 1 is formed. Coupling capacitors PD+, PD2, PI)I that output phase voltage signals VR, V, , VT are attached to each phase R1S, T, and each coupling capacitor PD+, PDz, PD, outputs a phase voltage signal vR, v, , V, (7) Voltage signal processing circuit 12 that performs predetermined signal processing and zero-phase voltage generation based on human power.
It is connected to the. The output of the phase voltage signal V of the voltage signal processing circuit 12 is sent to the output section 21a, the output of the phase voltage signal V is sent to the output section 21b, and the output of the phase voltage signal V is sent to the output section 21c.
, the zero-sequence voltage signal■. The outputs thereof are respectively connected to the output section 21d, and further connected to the ground point 23 via the lead wire 22. In addition, the distribution line 1 includes current transformers 111I and 118 that output phase current signals L and Is for each phase.
fly, and a current transformer (ZCT) that outputs the zero-phase current signal r0.
) 13, the current transformer 11 is connected to the grounding point 23 via series-connected resistors R+ and Rz, and the input side of the resistor R1 is connected to the output part 21f to output the phase current signal ■ , and the input side of the resistor R2 is connected to the output section 21e to output the short circuit current signal 0C11. In addition, the current transformer 113 is connected to the ground point 2 via the resistor R1.
3 and the input side of resistor R3 is connected to output section 21g.
The current transformer 1b is connected to the ground point 23 via the resistor R4, and the input side of the resistor R4 is connected to the output section 21h to output the short circuit current signal Oゎ. Signal 09. is output. Current transformer 13 is connected to output section 21i. The high pressure sensor 10 has such a configuration. The output section 21a of the phase voltage signal V and the output section 21f of the phase current signals f and I are connected to the power transmission direction determination circuit 14, and the power transmission direction determination circuit 14 receives the phase voltage signal v.
, l and the phase current signal I, the power transmission direction of the overhead power distribution line is determined. If the phase difference θ of the phase voltage signal V If it is within the range of 290°, the power transmission direction of the overhead power distribution line is determined to be reverse transmission. This power transmission direction determination circuit 14 is connected to a phase inversion circuit 17, and outputs a direction signal based on the determination result of the power transmission direction. for example,
When the power transmission direction is progressive, output part A is "1" and output part B
outputs a direction signal of “0” and the power transmission direction is reverse transmission,
Output section A outputs a direction signal of "0" and output section B outputs a direction signal of "1". On the other hand, the ground fault detection circuit 15 receives a zero-phase voltage signal v0.
output section 21d and zero-phase current signal ■. The output section 21i of is connected, and the ground fault detection circuit 15 receives the zero-phase voltage signal v0
and zero-sequence current signal■. Ground faults are detected based on the voltage level and current level. In other words, in the case of a 6KV distribution line, the zero-sequence current signal! . level is 100mA,
When the level of the zero-phase voltage signal v0 reaches 380■, it is recognized that a ground fault has occurred, and the zero-phase voltage signal ■ is determined based on the detection of the ground fault. , and zero-sequence current signal■. is output to the connected phase inversion circuit 17. The phase inversion circuit 17 generates a zero-phase current signal ■ based on the input direction signal output from the power transmission direction determination circuit 14. Controls the phase inversion of . That is, if the direction signal output from the power transmission direction determination circuit 14 is sequential, in other words, the output part A of the power transmission direction determination circuit 14
When "1" is output from output section B and "0" is output from output section B,
The phase inversion circuit 17 receives the zero-phase voltage signal ■ input from the ground fault detection circuit 15. , and the zero-phase current signal I0 are passed through as they are and output on the connected phase comparison circuit 1, and when the direction signal output from the power transmission direction determination circuit 14 is reversely transmitted, in other words, the direction signal output from the power transmission direction determination circuit 14 is "0" from output part A
However, when "1" is output from the output section B, the phase inversion circuit 17 outputs a zero-phase current signal ■.

The phase of is inverted, and an inverted zero-sequence current signal T0 and a zero-sequence voltage signal ■ are obtained. is output from the connected phase comparator circuit. The phase comparator circuit 18 receives the zero-sequence voltage signal v0 and the zero-sequence current signal (■) output from the phase inversion circuit 17. phase difference or zero-sequence voltage signal■. Based on the phase difference between the current signal T0 and the inverted zero-phase current signal T0, it is determined whether the direction of the fault point is on the power supply side or the load side. That is, for example, the zero-phase voltage signal ■. If the phase difference θ between the zero-phase current signal to, or the inverted zero-phase current signal T0, is within the range of 45 degrees of delay to 135 degrees of advance, it is determined that there is an accident on the load side. If it is within the range of 315'', it is determined that there is an accident on the power supply side.

When the second phase comparison circuit 18 determines that there is an accident on the load side, it outputs an accident signal to the connected indicator lamp blinking circuit 19. On the other hand, the output section 21e of the short circuit current signal OCR, the output section 21g of the short circuit current signal Oc5, and the output section 21g of the short circuit current signal OCR
The short circuit detection circuit 16 to which the output section 21h of 6〒 is connected detects a short circuit accident based on the current level of the input short circuit current signals Oc, I, QCs, OcA. When reaches 300 A, and
In the case of a large-capacity distribution line, a short circuit is detected when the current reaches 600A. Short circuit detection circuit 1
6 detects a short circuit accident, it outputs a detection signal to the indicator light blinking circuit 19.

The indicator lamp blinking circuit 19 blinks the connected indicator lamp 20 based on the input of the accident signal from the phase comparison circuit 18 and the input of the detection signal from the short circuit detection circuit 16.

The present invention will be explained in detail below.

The coupling capacitors PDISPDz and PDz constantly detect phase voltages and output phase voltage signals V, , V, , and Va to the voltage signal processing circuit 12. Voltage signal processing circuit 1
2 inputs the phase voltage signal VR1■5,■, performs predetermined signal processing, and generates the zero-phase voltage signal ■. is generated, and the phase voltage signal VR is sent to the power transmission direction discriminating circuit 1 via the output section 21a.
4, zero-phase voltage signal ■. is output to the ground fault detection circuit 15 via the output section 21d. Meanwhile, at the same time, the current transformer 11
N, 113, lb always detects phase current, current transformer 13 detects zero-sequence current, current transformer 11R, lls
, lb is a phase current signal It proportional to the phase current, ■5, ■
, and the current transformer 13 generates a zero-sequence current signal I0, respectively.

The phase current signals I, l are voltage-converted by resistors R1 and R2, and sent to the power transmission direction determination circuit 14 via the output section 21f.
11 to the short-circuit detection circuit 16 via the output section 21e, and the phase current signal (2) to the short-circuit detection circuit 16 via the output section 21g to the short-circuit current signal OCS converted into voltage by the resistor R1. The signal (a) outputs the short circuit current signal OCT, which has been voltage-converted by the resistor R4, to the short circuit detection circuit 16 through the output section 21h, and the zero-sequence current signal Io generated from the current transformer 13 is output through the second output section. and is output to the ground fault detection circuit 15. When the power transmission direction determination circuit 14 receives the phase voltage signal VR and the phase current signal E, it determines whether the power transmission direction is forward or reverse based on the phase difference, and sends a direction signal to the phase comparison circuit 17. Output. The ground fault detection circuit uses a zero-sequence voltage signal V0 and a zero-sequence current signal ■.

When input, ground fault detection is performed based on predetermined voltage and current levels. Further, the short circuit detection circuit 16 includes a short circuit current signal 0CR1, a short circuit current signal OC3,
When a short circuit current signal of 0.7 is input, a short circuit accident is detected based on a predetermined current level.

In this way, the power transmission direction determination circuit 14, the ground fault detection circuit 15,
The short circuit detection circuit 16 determines the power transmission direction, detects a ground fault, and detects a short circuit. At this time, if a ground fault occurs on either the power supply side or the load side of the overhead distribution line, the ground fault detection circuit 15 outputs the zero-sequence voltage signal vo and the zero-sequence current signal ■. The phase inversion circuit 1
7 and the phase inversion of the zero-phase current signal I0 is controlled based on the direction signal output from the power transmission direction determination circuit 14. That is, when the direction signal is a reverse signal, it is output as an inverted zero-phase current signal T0. A zero-phase voltage signal ■ is sent from the phase inversion circuit 17 to the phase comparison circuit 18. , and zero-sequence current signal T0, or inverted zero-sequence current signal ■. When is output, phase comparison time! 1B is a zero-phase voltage signal■. , and zero-sequence current signal I. , or determine whether the direction of the ground fault is on the power supply side or the load side based on the phase difference of the inverted zero-phase current signal T0, and when it is determined that the direction is on the load side, the fault signal is sent to the indicator light blinking circuit 1.
Output to 9. The indicator light blinking circuit 19 causes the indicator light 20 to blink based on the input of the accident signal, thereby indicating an accident to the operator. Further, when a short circuit accident occurs on the load side, the short circuit detection circuit 16 directly outputs a detection signal to the indicator light blinking circuit 19, and the indicator light blinking circuit 19 blinks the indicator light to notify the operator of the accident.

In this way, since the indicator light 20 blinks, it becomes clear that the accident direction is the load side, so that the accident point can be quickly discovered.

In the first embodiment, resistor R1 is omitted and current transformer IL
A current transformer may be attached to the lead wire of t, and the phase current signal IR may be obtained from the current transformer.

FIG. 2 shows a second embodiment of the present invention, in which the current transformer 13 in FIG. 1 is omitted and each phase has a current transformer 11*lb, .
By attaching A, a high voltage sensor 10 is provided for each phase, and a zero-sequence current is generated from the current signal processing circuit 25. , short circuit current 0CR1068, aCt are output.

The other parts are indicated by the same reference numerals as in the first embodiment, so the explanation will be omitted. This embodiment has two signal processing circuits for each phase.
Since current transformers 11R, 1°, and 11A are provided to input to the terminals 5 and 5, no special combination is required for connection. Also,
The connection portion of each high pressure sensor 10 can be easily inserted and removed using a plug 30.

FIG. 3 shows a third embodiment of the present invention, in which the current transformer 11s-1IIT- of FIG. 2 is omitted from the S phase and T sum. Therefore, colors are used to distinguish the R-phase high-pressure sensor 10 from the S-phase and T-phase high-pressure sensors IO.

〔Effect of the invention〕

As explained above, according to the fault direction determination device for an overhead distribution line of the present invention, the first detection means detects the phase voltage and phase current of the overhead distribution line, and the phase voltage and phase current of the The power transmission direction of the overhead distribution line is determined based on the phase difference of the overhead distribution line, and the zero-sequence current and zero-sequence voltage of the overhead distribution line are detected by the second detection means, and the voltage value of this zero-sequence voltage and the zero-sequence Ground faults are detected based on the current value of the current, while short circuits in overhead distribution lines are detected based on the phase current input of all phases, and the power transmission direction and the phase difference between the zero-sequence voltage and zero-sequence current are detected. The direction of the ground fault is determined based on the
A specified display is displayed when the direction of a ground fault is on the load side or when a short circuit is detected, making the direction of the fault clear and allowing the point of fault to be quickly discovered, thereby facilitating recovery work. can be done quickly.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention, Fig. 2 is an explanatory diagram showing a second embodiment of the invention, and Fig. 3 is an explanatory diagram showing a third embodiment of the invention.
FIG. 2 is an explanatory diagram showing an example. Explanation of symbols 1・−・−・・・−Single core cable 10−・−・−
--1--High pressure sensor 11m, its, lb-
・-・・-・-・-Current transformer 11R1, 11, 111-
・−・・−・−・−Current transformer 12−・−・−・～Voltage signal processing circuit 13−・−−−1−・・・−1 Current transformer 1 t−−−−
−−−−−−−−−−Power transmission direction determination circuit 15・−・−
・・・・・−・−・−Ground fault detection circuit 16−−−−−−−
−−・−・・−Short circuit detection circuit 17−−−−−・−・
−・Phase comparison circuit 8・・・−・−・−・−・Phase comparison circuit 19・・・・−−−−−111−−Indicator light blinking circuit 20・−・−−−−− ---Indicator lamps 21a to 21i・-・−・−・・−・・Output section 22
・・ -Earth 23・ Grounding point 25−・
...--Current signal processing circuit P DI, P D
z, P Dx '-------------・--Coupling capacitor R, -R,・----1-----Resistance ■3, ■5, ■, -1 -phase current signal V, ,V,
, V, −・−−−−−−−・−−・Phase voltage signal 0
CR1OCS, OCT -"'-'-" Short circuit current signal■.・・−・−・−・−・・・Under zero-sequence current signal. −
・・−・・−・−・Inverted zero-sequence current signal■. ------
1－－－－・－・・・Zero phase voltage signal patent applicant Saneisha Seisakusho Co., Ltd.

Claims (1)

[Scope of Claims] A first detection means for detecting a phase voltage and a phase current of an overhead distribution line; a second current detection means for detecting a zero-sequence current and a zero-sequence voltage of the overhead distribution line; power transmission direction determining means for determining the power transmission direction of the overhead power distribution line based on the phase difference between the phase voltage and the phase current of the phase; a ground fault detection means for detecting a ground fault; a short circuit detection means for detecting a short circuit in the overhead distribution line based on input of the phase currents of all phases; a ground fault direction determining means for determining the direction of the ground fault based on a power transmission direction and a phase difference between the zero-sequence voltage and the zero-sequence current; when the direction of the ground fault is determined to be on the load side; Alternatively, an apparatus for determining the direction of an accident in an overhead power distribution line, further comprising display means for displaying a predetermined display when the short-circuit accident is detected.