JPH071981B2 - Distribution line accident section detection relay device - Google Patents

Description

The present invention relates to a device capable of setting and changing the ground fault detection sensitivity of a relay having a ground fault detection function in a high voltage distribution system from a remote master station. .

[Conventional technology]

When installing a relay with a ground fault detection function on the distribution line,
When a certain ground fault detection sensitivity is to be obtained due to the difference in the system condition of the installation point, that is, the primary side ground charging current, the secondary side ground charging current, etc., the set value of each relay, that is, zero phase voltage, zero Phase current set value is different. In such cases,
In the past, the work was to go to each installation point, climb a utility pole, and set the taps on the relay.

[Problems to be solved by the invention]

Since such a conventional sensitivity setting operation has to be carried out at each installation location of a large number of relays, there is a problem that the operation is complicated and takes a lot of time and effort. Also, when changing the power distribution system,
There was a problem that work was required each time and the burden was heavy.

The present invention has been made in view of such conventional problems, and an object of the present invention is to eliminate the work at the site when setting and changing the ground fault sensitivity.

[Means for solving problems]

In order to achieve this object, the distribution line protection relay device of the present invention includes a distribution substation busbar, a distribution circuit breaker, an accident detection device,
In a distribution system consisting of a division switch, a normally open division switch for reverse transmission and transmission, and an electric wire connecting them, a ground fault accident detection function is installed at each division switch installation location.
The ground fault detection of each of the slave stations is performed by installing the slave stations having the variable sensitivity function of ground fault detection and the communication function with the master station, and the master station having the communication function for these slave stations. It is characterized in that means for controlling the sensitivity varying function in the master station is provided.

〔Example〕

Hereinafter, the present invention will be specifically described based on the embodiments shown in the drawings.

FIG. 1 is a block diagram showing a control system of the present invention.
In the figure, CB1 is a circuit breaker connected to the busbar from the substation A, and CB2 is a circuit breaker connected to the busbar from the substation B. Section switches DM1, DM2 and DM3 are connected to the high voltage busbar from the circuit breaker CB1. Also, circuit breaker CB
A section switch DM4 is connected to the high voltage bus bar from 2. DM5 to DM8 are normally open section switches, which are normally in an open state, but are installed to supply electric power from another high voltage bus when an accident occurs in a certain section.

The above-mentioned division switch is provided with slave stations 1 to 8 for opening and closing them respectively from the master station 20. As shown in FIG. 1, when a ground fault occurs in the second section, the slave station 1 of the section switch DM1 first has the normally open section switch DM1.
5 and DM7 slave stations 5 and 7 are set to output a closing command signal through the communication line 30 and then output an open signal to the section switch connected to the ground fault accident section. Keep it. As a result, when an accident occurs in the second section, the normally open section switches DM5 and DM7 are turned on, reverse transmission and interchange power transmission to the third section and the fourth section is performed, and then the section switches DM1, DM2 and DM3 shuts off and the second section where the accident occurred is cut off.

FIG. 2 is a block diagram showing the configuration of each slave station 1 to 4.

A zero-phase current transformer ZCT, a zero-phase voltage detector ZPD, and an overcurrent detection current transformer CT for overcurrent lock are installed on the distribution line. It is input to the waveform shaping circuit 81, the zero-phase voltage detection / waveform shaping circuit 82, and the overcurrent detection / waveform shaping circuit 83. These circuits 81, 82,
The output signal of 83 is output as a digital signal because it is digitally processed by the microcomputer. Each signal is input to the CPU 85 through the input / output interface 84. The CPU85 detects the levels of zero-phase current and zero-phase voltage, and from the phase of the zero-phase current and the phase of the zero-phase voltage, a ground fault is detected on the power supply side or the load side of each section switch installation location. It is determined whether or not it is output as a ground fault occurrence direction signal. Hereinafter, the power source side and the load side will be referred to as “A” and “B” for a certain switch.

In the present embodiment, as the place絡発raw direction signal, direction signal I _A that it is the A-side, the direction signal I _B that is a B-side, the direction signal that it is not A side O _A, direction signal O _B that is not a B-side 4 signals are output as energizing signals for each relay. Here, I _A and O _B , and I _B and O _A are signals output under the same conditions, respectively, but the latter is set so that the latter has a lower operating level than the former, and The sensitivity is set so that it operates quickly. In FIG. 2, reference numeral 86 is a ROM for storing the operation program of the CPU 85, 87 is an input / output interface, 88 is a switch breaking circuit, and 89 is a switch closing circuit. An opening signal and a closing signal are provided. Reference numeral 90 is a ground-fault section detection logic circuit, 91 is a rewritable ROM, and is a non-volatile external memory for storing operation level setting values such as zero-phase current and zero-phase voltage.
Is a communication circuit that communicates with the master station via a pair of communication lines and outputs a normally open division switch closing command signal in the event of a ground fault. The ground fault section detection logic circuit 90 transmits / receives the ground fault direction signal of itself and the ground fault direction signal of the adjacent switch to detect the ground fault section.

The function of setting the sensitivity of the zero-phase current and the zero-phase voltage in the present invention will be described. The communication circuit 92 shown in FIG. 2 has a built-in communication modem so that it can communicate with the master station 20 via the communication line 30 (see FIG. 1). Based on this, the taps that define the sensitivity of the operating voltage and current can be switched.

An example of the algorithm of the proper tap value will be described based on the flowchart shown in FIG.

(1) Input of data (steps 100 and 101 in FIG. 3) (a) Input the corresponding bank, the corresponding line number, and the slave station number for which the proper tap value is to be calculated, using the keyboard of the master station 20.

(B) Input the charging current I _C0 (A) of the entire system and the charging current I _C1 (A) of the corresponding line using the keyboard.

(C) Input the detected ground fault resistance value R ₉ (Ω) on the keyboard.

(D) The residual voltage V _0R (V) and residual current I _0R (A) of the slave station from which the master station wants to calculate an appropriate tap value is read by communication.

It is assumed that the data related to the slave station connected to the relevant line is secured in the master station table including the address.

(2) Calculation of operation target values V _0VG and I _DG (step 102 in FIG. 3) (a) The charging current is converted into admittance.

Y _F1 = I _C1 / E _a …… Y _F2 = (I _C0 −I _C1 ) / E _a …… However, E _a is the zero-phase voltage when the line is completely grounded, and the line voltage Is.

(B) Calculate zero-phase voltage V ₀ and zero-phase current I ₀ .

I ₀ = Y _F2 · V ₀ …… (c) Ground fault voltage operation target value V _0DG , ground fault current operation target value
Calculation of I _DG V _0VG = V ₀ −V _0R …… I _DG ＝ I ₀ −I _0R …… I _DG = 4I _0R …… However, I _DG takes either the formula or the value of the formula, whichever is larger. I shall.

(3) Selection of appropriate tap value (step 103 in FIG. 3) An appropriate tap value of the zero-phase voltage V ₀ , the zero-phase current I ₀ and the phase angle θ is selected. Here, the zero-phase voltage V ₀ is represented by% of the zero-phase voltage at the time of complete ground fault.

V ₀ : 1,2,3,4,5,7.5,10 (%) I ₀ : 0.2,0.3,0.4,0.5,0.6,0.8,1.0 (A) θ: 30,60,90 degrees (of the wiring system It is selected according to a constant.) (A) 2 which is close to the values of V _0VG and I _DG obtained by the above formula
Select one tap value. These are V ₀₁ , V ₀₂ and I ₀₁ , I ₀₂ , respectively. However, V ₀₁ <V ₀₂ and I ₀₁ <I ₀₂ .

(B) As for the zero-phase ground fault voltage, since it is a backup relay and it is necessary to operate it first as a condition,
Keep high sensitivity. Therefore, tap V
_0TAP = V ₀₁ .

(C) The following selection method is used for the ground fault current.

When V _0TAP = 0.2A c.:0.2A<I _DG <1.0A when when the a.:I _DG ≧ 1.0A of _{I 0TAP = 1.0A b.:I DG ≦ 0.2A} , i) I DG When _≤0.6A, I _0TAP = I ₀₁ ii) When I _DG > 0.6A, calculate the difference between I _DG and I ₀₁ , I ₀₂ , and select the one with the smaller difference.

(4) Calculation of detection sensitivity range with respect to tap value (step 104 in FIG. 3) _{Based on} the _{values of} V _0TAP , I _0TAP and residual voltage V _0R , residual current V _0R obtained in (3), zero-phase ground fault _Obtain the maximum and minimum values of voltage detection sensitivity R _qV and zero-phase ground fault current detection sensitivity R _qI .

R _q1 <R _qV <R _q2 R _q3 <R _qI <R _q4 However, the calculation formulas for R _{q1 to} R _q4 are as _follows .

Also, from the obtained R _{q1 to} R _q4 , the maximum sensitivity and the minimum sensitivity are obtained under the following conditions.

Maximum sensitivity R _qmax = smaller value by comparing R _q2 and R _q4 Minimum sensitivity R _qmin = smaller value by comparing R _q1 and R _q3 (5) The obtained value is CRT display or necessary To print out (step 105 in FIG. 3).

The items are as follows.

Date, time, applicable bank, line number, slave station number, _V0TAP
Value (IN, OUT), I _{0 TAP} value (IN, OUT), θ _TAP value, detection sensitivity
R _qmax , R _qmin (6) When setting the above values (Step 10 in Fig. 3)
6) outputs a setting command to each slave station through the communication line (step 107). The set value is confirmed by polling each slave station (step 108).

Through the above processing, it becomes possible for the master station 20 to set and change the appropriate tap value of the ground fault detection sensitivity for each slave station.

〔The invention's effect〕

As described above, in the present invention, a master station having a communication function is installed for a slave station provided at each section switch installation location, and the ground fault accident detection sensitivity of each slave station from the master station is set. It can be set and changed by operation. This allows you to go to the place where each switch is installed,
There is no work of climbing up the utility pole and setting the taps of the relays, and it is possible to realize significant work efficiency and labor saving. Further, even when the distribution system of electric power is changed due to undergrounding of the electric wire, the power demand situation, etc., it is possible to promptly respond.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration example of a relay device of the present invention, and FIG.
FIG. 3 is a block diagram of a configuration example of a slave station, and FIG. 3 is a flowchart showing a procedure for setting the ground fault detection sensitivity from the master station to the slave station. CB1, CB2: Circuit breaker DM1 to DM8: Divided switch 1 to 8: Slave station 20: Master station 30: Communication line 81: Zero-phase current detection / waveform shaping circuit 82: Zero-phase voltage detection / waveform shaping circuit 83: Overcurrent Current detection / waveform shaping circuit 84,87: I / O interface 85: CPU 86: ROM 88: Switch open circuit 89: Switch closing circuit 90: Ground fault section detection logic circuit 91: ROM

Front page continuation (72) Hideto Kawazoe, No. 1 Oitakitamachi, Saga City, Saga Prefecture, Toga Denki Seisakusho Co., Ltd. (72) No. 1 Oitakitamachi, Saga City, Saga City, Raga Togami Denki Seisakusho

Claims (1)

[Claims] 1. A distribution system comprising a distribution substation busbar, a distribution circuit breaker, an accident detection device, a section switch, a normally open section switch for performing reverse transmission and transmission, and an electric wire connecting them to each other, Each of the division switches is provided with a slave station having a ground fault accident detection function, a ground fault accident detection sensitivity variable function, and a communication function with the master station, and has a communication function for these slave stations. A distribution line fault section detection relay device comprising a master station, and means for setting and changing the ground fault accident detection sensitivity of each slave station in the master station.