JPH0773408B2 - Loop switching device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a loop switching device for performing reverse switching power transmission in a distribution system and a loop switching back operation for returning the distribution system to a normal system. It is a thing.

[Conventional technology]

In the non-grounded distribution system, in order to minimize the power outage section and to quickly find the failure point when the distribution line fails, the distribution switch has a division switch that is divided into predetermined sections and a loop point switching line that interchanges power. It is installed.

Fig. 2 is a distribution system diagram in which the distribution lines from the three distribution substations that are connected by the same system (not shown) are connected by loop point switches.
AS / S, BS / S and CS / S are distribution substations A, B and C, respectively.
1 is a bus of distribution substation AS / S, 2 is a bus of distribution substation BS / S, 3 is a bus of distribution substation CS / S, CB1 is a circuit breaker connected to bus 1, CB2 Is a circuit breaker connected to the bus 2, CB3 is a circuit breaker connected to the bus 3, F1 is a circuit breaker connected to the other terminal of the circuit breaker CB1 to supply power to the customer, F2 is a circuit breaker
The distribution line F2 connected to the other terminal of CB2 to supply power to the customer is the distribution line F2 connected to the other terminal of the circuit breaker CB3 to supply power to the customer, and SS11 and SS12 are distribution lines F1. SS2, a sorting switch for sorting at regular intervals
1, SS22, SS31 are respectively section switches, SS20, SS30 are loop point switches, S13, S21, S22, S23, S31, and S32 are sections sectioned by section switches, 11, 12, 21, 22 , 31 is a switch
It is a slave station for SS11, SS12, SS21, SS22, SS23, and has actual cross current prediction means.

20 and 30 are slave stations for loop point switches SS20 and SS30, and have actual cross current prediction means. 11-1 and 11-2 are service lines for pulling the voltage across the divisional switch SS11 to the slave station 11, and 11-3 is for controlling the switching of the divisional switch SS11 from the slave station 11 and detecting its state. Control line, 12-1, 12-2, 21-1, 21-2,
22-1, 22-2, 31-1, 31-2 are sectional switches SS12, SS21, SS2
2, Drop-in wire for pulling the voltage across SS31 to slave stations 12, 21, 22, 31; 12-3, 21-3, 22-3, 31-3 are slave stations 12, 21, 22, 31
Control switches for controlling the opening and closing of the sectional switches SS12, SS22, SS21, SS31 and detecting the state of the switches, 20-1, 20-2,
30-1 and 30-2 are drop lines for pulling the voltage across loop point switches SS20 and SS30 to slave stations 20 and 30, and 20-3 and 30-3 are loop points from switch stations 20 and 30 to SS20. , A control line for controlling the opening and closing of SS30 and detecting its state, 40 is a master station,
It is a selection means for selecting the case where the actual cross current has the smallest effect on the distribution system.
It has 0B. 50 is the parent station 40 and the child stations 11, 12, 20, 21, 22, 30,
It is a communication line for data transmission with 31.

FIG. 3 is a block diagram showing the configuration of the slave station shown in FIG.
In the figure, the same numbers as those in FIG. 2 indicate the same or corresponding portions, 20-4 is a switch, 20-5 is a control line for controlling the opening and closing of the switch 20-4, and 20-6 is the voltage on both sides of the loop point switch SS20. Transformer for detecting voltage difference, 20-7
Is a switch, 20-8 is a control line for controlling the opening and closing of the switch 20-7, 20-9 is a current transformer for detecting the cross current, 20-10 is a control circuit for detecting the cross current, and Zc is an impedance for detecting the cross current. FIG. 4 is a block diagram showing the principle of cross current detection,
In the figure, the same numbers in Fig. 3 indicate the same or equivalent parts, Za is the impedance for the distribution substation AS / S seen from the loop switch SS20, and Zb is the distribution substation for the loop switch SS20. This is the back impedance as seen by BS / S.

Next, the operation will be specifically described with reference to the block diagrams showing the configurations of FIGS. 2 and 3 and the block diagram showing the principle of the cross current detection of FIG.

First, the slave stations 11,12,21,22,31,20,30 with cross current detection function are installed for each of the segment switches SS11, SS12, SS21, SS22, SS31 and the loop point switches SS20, SS30. The slave stations such as are connected to the master station 40 by a communication line 50 for exchanging data.
The master station 40 collects the cross current detection value detected by each slave station by the polling method. At this time, the distribution line F1 of the distribution substation AS / S
Power outage work is required in the second section S12, and this section will be cut off. That is, assuming that it is necessary to switch to the power outage section, first, in order to prevent the power outage of the third section S13 of the distribution line F1, the loop point switch SS20 or SS30 is turned on to form a loop, and then the section switches SS12 and SS11 are opened. There is a need to.

Before turning on the loop switch SW20 or SS30, check the cross current detection value from the slave stations 20 and 30 collected by the master station, and check which loop switch has the smaller effect on the distribution system. Judge and select the optimum loop point switch.

For this check, the total value of the cross current and the load current should be less than the operating value of the overcurrent protection relay for the distribution line of the distribution substation, that is, the distribution breaker should not be cut off.
Based on the minimum required conditions, such as being less than the breaking capacity of the division switch, and the voltage of the distribution line being within the specified value, the cross current is as small as possible and the loop point switch with a large power interchange capacity margin. Select.

Incidentally, the load current of the distribution line, the calculation of the power interchange capacity margin, etc. are calculated as necessary from the load capacity for each section registered in advance in the database in the master station 40 and the bank capacity of the distribution substation, Alternatively, the current data of the distribution line collected online through the data transmission system is combined with the above-mentioned database and calculated as necessary.

The optimum loop point switch selected by the above check is
A closing command is sent from the master station 40 to the slave station, and the loop point switch is closed to form a loop. Then child station 1
The master station 40 sequentially sends an opening command to 2, 11 to open the section switches 12, 11 to set the second section of the distribution line F1 as a power failure section and complete the switching operation.

Next, the operation of the slave station is shown in FIG.

In the slave station 20, the voltage on both sides of the normally open loop point switch SS20, that is, the voltage of the distribution line F1 of the distribution substation AS / S and the distribution substation BS
The voltage of the distribution line F2 of / S is drawn in by the lead lines 20-1 and 20-2. Assuming that the differential voltage between both sides is ΔV, the voltage between both sides ΔV is detected by the differential voltage detecting transformer 20-6 by turning on the switch 20-4, and is sent to the control circuit 20-10 and stored therein.

Next, after opening the switch 20-4, the switch 20-7 is turned on, and the cross current detection impedance Zc is inserted between both sides of the loop point switch SS20. Assuming that the cross current flowing at this time is Ic, the cross current Ic is detected by the cross current detecting current transformer 20-9, and the control circuit
It is sent to 20-10 and stored. After that, the switch 20-7 is opened.

Through the above series of operations in the slave station, the control circuit 20-10 stores the differential voltage ΔV across the loop point switch SS20 and the cross current Ic when the cross current detection impedance Zc is inserted.
Calculation of the cross current value (actual cross current value) when the loop point switch SS20 is actually closed will be described using these values with reference to FIG.

The impedance when looking at the distribution substation from both sides of the loop switch SW20 is called the back impedance, and the back impedance when looking at the distribution substation AS / S side is Z _A , and the distribution substation BS / S side If we assume that the back impedance is Z _B , the cross current Ic has the following relationship.

From the above relation, the sum of the background impedances Z _A and Z _B is

Therefore, when the loop point switch SS20 is actually turned on, the cross current value I is obtained by the following equation and can be predicted.

By performing the above calculation by the control circuit 20-10, it is possible to predict the actual cross current value when the loop point switch SS20 is actually turned on without having the back impedance as a database in advance.

The magnitude of the cross current detection impedance Z _C is large enough not to affect the distribution system (for example, the line voltage does not change) when it is inserted (when the switch 20-7 is closed), for example, the back impedance Z _A. , Z _B to several tens to several hundreds of times.

[Problems to be Solved by the Invention]

Since the conventional loop switching device is configured as described above, a cross current detector is provided on at least one of the loop point switch and the section switch, and the cross current value flowing when the loop point switch or the section switch is closed is set. In addition to detecting this cross current detector in advance, the master station collects these cross current values via the data transmission system, and when it is looped, the optimum loop point switch or section switch with little influence on the system is selected. After selecting and turning on the selected loop point switch or section switch via remote control via the data transmission system, open the relevant section switch or loop point switch for a power failure section by remote control, The switching operation is performed without a power failure, or the switchback operation is performed in reverse of the switching operation.

However, if the cross current detection value is too large at the time of loop switching, an unnecessary power failure will occur due to the trip of the circuit breaker of the distribution substation, or the circuit breaker or loop point switch will not be able to cut off. There was a problem.

The present invention has been made to solve the above problems, and provides a loop switching device that predicts a time zone in which a cross current value becomes small based on past accumulated data even when the actual cross current value is excessive. With the goal.

[Means for Solving the Problems]

The loop switching device according to the present invention includes a plurality of slave stations having actual cross-flow predicting means connected to a plurality of distribution lines divided by the division switch and the loop point switch, and the actual cross-flow predicting means measures the constant time. The computer in the master station that saves the detected cross current detection data by month, day, weekday, holiday, and loop point, and the actual cross current prediction data is created based on the cross current detection data. This is composed of a display means in the master station that visually represents a loopable time zone from the cross current prediction data and makes it possible to determine whether or not looping is possible, and the loopable time zone can be selected.

[Action]

The computer in the master station according to the present invention accumulates the cross current detection data of the loop point switch element, predicts the time zone when the cross current value is equal to or less than the cutoff capacity of the segment switch element, and has a small influence on the distribution system. Since switching is performed, the breaking capacity of the breaker will not be exceeded. Also, it becomes possible to accurately predict the operation timing of the circuit breaker.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. In the figure, the same parts as those in FIG. 2 are shown with the same reference numerals in FIG. 1, the figure is an illustration of the cross current data at the loop point of the distribution line, and the figure (b) is a graph of the figure (a). FIG.

The slave station in Fig. 2 detects the cross currents of the loop point switches SS20 and SS30 on an hourly basis, temporarily stores the measured data in its own station, and the master station 40 acquires the stored data of the slave station at regular intervals. As shown in FIG. 1, the trend data is organized and stored as month, day, weekdays, Sundays, holidays, and loop points. For the cross current detection data measured at each hour, the average value with the data of the same month, day and hour of the previous year is calculated and saved as master data.

Then, when the power interchange becomes necessary, the trend of the cross current is checked, and the cross current value in the cross point data at the loop point on the day indicates that the cross current value is a power failure, a voltage drop, a break switch, a breakage capacity of the loop switch, etc. Select a time zone that has less impact on consumers and distribution systems, and exchange power during that time zone. Then, for example, as shown in FIG. 1 (b), the trend of the cross current can be seen at a glance and visually drawn as the data of one day on the display means 40B of the master station 40 so that it can be displayed at any time as needed. To do.

All of these operations are performed by the existing computer 40A in the master station 40. In the above embodiment, the example of storing the lateral flow data at the loop point by year, month / day, weekday, Sunday, etc. is explained, but the aim is to know the trend of cross current, that is, the actual cross current predicted value. , It doesn't particularly care about the preservation category.

〔The invention's effect〕

As described above, according to the present invention, the cross current detection data of the loop point is accumulated in the computer of the master station, the cross current value is equal to or less than the breaking capacity of the switchgear, and the time period during which the influence on the distribution system is small is displayed. Even if the cross current detection value becomes too large when loop switching is performed and it becomes impossible to perform it, the cross current value will be small based on the past accumulated data. There is an effect that it becomes possible to predict the time zone.

In addition, based on this cross current data, the optimum switch or loop point switch for looping in the master station is selected and automatically operated, so the influence on the distribution system is minimized. Therefore, the loop switching operation and the loop reverting operation can be performed with high reliability without affecting the customer and with a minimum number of personnel who have reduced the number of local operations.

[Brief description of drawings]

1 (a) and 1 (b) are explanatory views of a display showing a trend of loop point cross current data showing an embodiment of the present invention, and FIG. 2 is a configuration diagram showing the present invention and a conventional distribution line loop switching device. 3, FIG. 3 is a block diagram showing the configuration of the slave station shown in FIG. 2, and FIG. 4 is a block diagram showing the principle of cross current detection. In the figure, 1 is an AS / S busbar, 2 is a BS / S busbar, 3 is a CS / S busbar, 1
1,12,20,21,22,30,31 are slave stations, 40A is a computer, 40B is a display means, 40 is a master station, 50 is a communication line, CB1 to CB3 are distribution breakers, and F1 to F3 are distributions. Electric wire, SS11, SS12, SS21, SS22, SS31 are section switches, SS20, SS30 are loop point switches. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshinobu Ebisaka 1-2-2 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Electric Corporation Control Works (72) Inventor Keiji Isahaya Kazu, Hyogo-ku, Kobe-shi, Hyogo Tazaki-cho 1-2-1 Mitsubishi Electric Co., Ltd. Control Factory (56) Reference JP-A-63-287324 (JP, A) JP-A-63-287321 (JP, A)

Claims (1)

[Claims] 1. A plurality of slave stations having actual cross-current predicting means connected to a plurality of distribution lines divided by a division switch and a loop point switch connected to a distribution substation, and the loop point switch. When the actual cross current predictor of the element receives the cross current detection data measured at a fixed time periodically through the communication line, it stores the data in the master station by month, day, weekday, holiday and loop point, and the cross current detection. Calculate the actual cross-current prediction data based on the data, store this actual cross-current prediction data as new data, and use the actual cross-current prediction data at the loop point of the day at the time of power interchange to create a loop with little effect on the distribution system. A loop switching device provided with a display means in the master station capable of proposing a proper time zone in a tendency to judge whether or not to make a loop.