JPH0799904B2 - Power interchange system for distribution system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power interchange system of a power distribution system that performs power interchange in the power distribution system.

[Conventional technology]

In the non-grounded distribution system, in order to minimize the power failure section and to detect the failure point early when the distribution line fails, the division switch that is divided into predetermined sections and the loop point switch that performs interchange transmission are used as the distribution line. It is installed.

Fig. 4 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 interconnected by loop point switches.
AS / S, BS / S and CS / S are distribution substations A, B and C, respectively.
(1) Bus for distribution substation AS / S, (2) Bus for distribution substation BS / S, (3) Bus for distribution substation CS / S, CB ₁
Is a circuit breaker connected to the bus (1), CB ₂ is a circuit breaker connected to the bus (2), and CB ₃ is a bus (3)
Distribution breaker connected to, F ₁ is distribution breaker CB ₁
The distribution line connected to the other terminal of the power supply to the consumer, F ₂ is the distribution line connected to the other terminal of the circuit breaker CB ₂ to supply power to the customer, and F ₃ is the distribution line A distribution line connected to the other terminal of the circuit breaker CB ₃ to supply power to the customers, SS ₁₁ and SS ₁₂ are division switches for dividing the distribution line F ₁ at predetermined intervals, SS ₂₁ and SS _22. Is a distribution switch for dividing the distribution line F ₂ at predetermined intervals, SS ₃₁ is a distribution switch for dividing the distribution line F ₃ at predetermined intervals, and SS ₂₀ is a distribution line F ₁
And the loop point switch for connecting the distribution line F ₂ with SS, SS ₃₀ is the loop point switch for connecting the distribution line F ₁ with the distribution line F ₃ , S
₁₁ , S ₁₂ , S ₁₃ show the section of the distribution line F ₁ divided by the circuit breaker CB ₁ , the section switches SS ₁₁ , SS ₁₂ and the loop point switch SS ₂₀ , and the section near the circuit breaker CB _1. The first section, second section, third section of distribution line F ₁ , S ₂₁ , S ₂₂ , S ₂₃ are circuit breakers CB ₂ ,
It shows the section of the distribution line F ₂ divided by the section switches SS ₂₁ , SS ₂₂ and the loop point switch SS _{20. From} the section closer to the circuit breaker CB ₂ , the first section and the second section of the distribution line F ₂ , 3rd section, S
_31, S ₃₂ are breaker CB _3, section switches SS ₃₁ and illustrates a section of a distribution line F ₃ which is divided by the loop point switch SS _30, the distribution line F ₃ from section close to the circuit breaker CB ₃ The first section and the second section.

Next, in the second section S ₁₂ of the distribution line F ₁ , an explanation will be given by taking as an example a switching operation in which the section is cut off in order to perform a power failure construction of the distribution line. First section S ₁₁ , second section S ₁₂ , third section S _{13 of} distribution line F ₁
Receives power only from the bus (1) of the distribution substation AS / S, and loop point switches SS ₂₀ and SS ₃₀ are open.
To this state blackout the second section S ₁₂ (called a blackout interval SESI shows a hatched portion in FIG. 4), first section switch
When SS ₁₂ is opened, the third section that is not the target of power outage construction S ₁₃
Becomes a power outage. The power failure time of the third section S ₁₃ the loop point switch SS ₂₀ was charged immediately after opening of the section switch SS ₁₂ in order to minimize the flexibility transmission from distribution substation BS / S in the third section S ₁₃ To do. After that, the sectional switch SS ₁₁ is opened and the second section S ₁₂ is opened.
To the power failure section.

By the above switching operation, the second section S ₁₂ can be made into a power failure section. For this switching operation, the switch is manually opened or closed, or, as described in JP-A-64-64535, the loop point switch SS ₂₀ is immediately turned on when a voltage on one side can be set externally. There is a system in which the loop switch SW ₂₀ is turned on at the same time when the sectional switch SS ₁₂ is opened.

[Problems to be Solved by the Invention]

Since the power interchange system of the conventional distribution system is configured as described above, after opening the partition switch surrounding the power failure section, until the loop point switch is turned on, the open partition switch and loop point There was a problem such as a power failure in the section between the switches.

By the way, it is possible to open the section switch after turning on the loop point switch to prevent a power failure in such a section, but there may be an excessive cross current when looping, When an excessive cross current occurs, the circuit breaker trips due to the overcurrent protection relay for the distribution line at the distribution substation, which causes a problem of power failure of the distribution line.

The present invention has been made to solve the above-mentioned problems, and it is possible to switch the distribution system without a blackout in a certain section, and to minimize the influence of the cross current generated at the time of switching. The purpose is to obtain a power interchange system for a power distribution system.

[Means for Solving the Problems]

The power interchange system of the distribution system according to the present invention, for each of the loop point switch in the open state among the plurality of loop point switches, predicts the cross current flowing when switching the switch to the closed state by the loop, The loop point switch with the smallest cross current is selected to switch to the closed state.

[Work]

The cross current detector according to the present invention is configured such that an impedance that does not affect the power distribution system is trial-inserted at both ends of the contact of the open loop point switch, and the current flowing at that time and the voltage between both ends of the contact before impedance insertion are used to distribute The loop point switch or section switch is turned on by obtaining the back impedance of the system so that the cross current when looping can be accurately obtained in advance, and the master station also obtains the cross current value from these cross current detectors. In addition, an optimum distribution system, that is, a loop point switch or a division switch can be selected from a plurality of distribution systems to be looped.

Example of Invention

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same numbers as those in FIG. 4 indicate the same or corresponding parts, and (11), (12), (21), (22), and (31) are section switching elements (hereinafter referred to as section switches) S ₁₁ , S ₁₂ , S ₂₁ , S
_22, in the slave station for S _31, a built-in actual lateral flow prediction means.

(20) and (30) are slave stations for loop point switching elements (hereinafter referred to as loop point switches) SS ₂₀ and SS ₃₀ , which incorporate actual crossflow predicting means. (11-1) and (11-2) are lead-in wires for leading in the voltage between both ends of the division switch SS ₁₁ to the slave station (11), and (11-
3) the control lines for detecting the state as well as opening and closing control section switch SS ₁₁ from the slave station 11, (12-1) (12
2), (21-1) (21-2), (22-1) (22-2),
(31-1) and (31-2) are sectional switches SS ₁₂ , SS ₂₁ , SS ₂₂ , SS
A lead-in wire for leading the voltage across ₃₁ to the slave stations (12) (21) (22) (31), (12-3) (21-3) (22-3) (31
-3) is a switch from the slave stations (12) (21) (22) (31)
Control lines for controlling the opening and closing of SS ₁₂ , SS ₂₁ , SS ₂₂ , and SS ₃₁ and detecting their states, (20-1) (20-2), (30-
1) (30-2) is a lead-in wire for leading the voltage across the loop switches SS ₂₀ , SS ₃₀ to the slave stations (20) (30), (20-3)
(30-3) is a loop point switch S from the slave station (20) (30)
A control line for controlling the switching of S ₂₀ and SS ₃₀ and detecting the state thereof, (40) is a master station, and is also a selection means for selecting a case where the actual cross current has a small effect on the distribution system. (Five
0) is the parent station (40) and the child stations (11) (12) (20) (21) (2
2) It is a communication line for data transmission with (30) and (31).

FIG. 2 is a block diagram showing the configuration of the slave station shown in FIG.
The configuration of the slave station (20) will be described as an example. In the figure, the same numbers as in FIG. 1 indicate the same or corresponding parts,
(20-4) is a switch, (20-5) is a switch (20-
4) a control line for switching control, (20-6) a differential voltage detection transformer for detecting the voltage difference between the voltages on both sides of the loop switch SS ₂₀ , (20-7) a switch, (20-8) ) is the control line which controls the opening and closing of the switch (20-7), (20-9) is cross flow detection current transformer (20-10) is a control circuit for detecting cross current, Z _c is a lateral flow detection impedance is there.

Fig. 3 is a block diagram showing the principle of cross current detection. In the figure, the same numbers as in Fig. 2 indicate the same or corresponding parts, and Z _a indicates the loop point switch SS ₂₀ to the distribution substation AS / S. The viewed back impedance, Z _b, is the back impedance when the distribution substation BS / S is viewed from the loop switch SS ₂₀ .

Next, the operation will be specifically described with reference to the block diagrams showing the configurations of FIGS. 1 and 2 and the block diagram showing the principle of the cross current detection of FIG.

First, the slave stations (11) (12) (21) (with the cross current detection function for each of the segment switches SS ₁₁ , SS ₁₂ , SS ₂₁ , SS ₂₂ and SS ₃₁ and the loop point switches SS ₂₀ and SS ₃₀ respectively. 22) (31) (20) (30) are installed, and these slave stations 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 second section S of the distribution line F ₁ of the distribution substation AS / S
_A power outage is required at ₁₂ and this section will be out of service. That is, assuming that it is necessary to switch to the power failure section, first, in order to prevent the power failure of the third section S ₁₃ of the distribution line F ₁ , the loop point switch SS ₂₀ or SS ₃₀ is closed and looped, and then the sectional switch SS ₁₂ It is necessary to open SS ₁₁ .

Before turning on the loop point switch SS ₂₀ or SS ₃₀ , check the cross current detection value from the slave stations (20) (30) collected by the master station, and which loop point switch is turned on is the distribution system. Select the optimum loop point switch, judging whether it has a small effect. For this check, the total value of the cross current and the load current must be below the operating value of the overcurrent protection relay for the distribution line at the distribution substation, that is, the distribution breaker must not be cut off. Select a loop point switch with a small cross current and a large margin of interchange capacity based on the minimum required conditions such as being less than or equal to the breaking capacity of the segment switch. It should be noted that the load current of the distribution line, calculation of the interchange capacity margin, etc. should be calculated from the load capacity for each section registered in advance in the master station (40) as a database and the bank capacity of the distribution substation, if necessary. Alternatively, the electric 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 sent from the master station (40) to the slave station, and the loop point switch is closed and looped. After that, the master station (40) sends a sequential opening command to the slave stations (12) and (11), opens the section switches (12) and (11), and sets the second section of the distribution line F ₁ to the power failure section. , Switching operation is completed.

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

Slave station (20) to the normally open voltage across the loop point switch SS _20, i.e. the voltage of the distribution line F ₁ and distribution substation BS / S of distribution substation AS / S of the distribution line F ₂ Voltage drop line (20-1)
(20-2) is pulling in. The difference voltage of the voltage between both ends is Δ
If the voltage is V, this differential voltage ΔV is detected by the differential voltage detecting transformer (20-6) when the switch (20-4) is turned on, and is sent to the control circuit (20-10) and stored therein.

Next, after opening switch (20-4), switch (20-4)
-7) is turned on and the cross current detection impedance Z _c is inserted between both ends of the loop point switch SS ₂₀ . Assuming that the cross current flowing at this time is I _c , the cross current I _c is detected by the cross current detecting current transformer (20-9) and is sent to the control circuit (20-10) and stored therein. After that, the switch (20-7) is opened.

Through the series of operations in the slave station described above, the control circuit (20-10) stores the differential voltage ΔV of the loop point switch SS ₂₀ and the cross current I _c when the cross current detection impedance Z _c is inserted. Calculation of the cross current value (actual cross current value) when the loop point switch SS ₂₀ is actually closed will be described using these values with reference to FIG. The impedance when looking at each distribution substation from both sides of the loop switch SW ₂₀ is called the back impedance.
Assuming that the back impedance looking at the distribution substation AS / S side is Z _A and the back impedance looking at the distribution substation BS / S side is Z _B , the cross current I _C is in the following relationship.

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

Therefore, the cross current value I when the loop point switch SS ₂₀ is actually turned on can be obtained and predicted by the following equation.

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

The magnitude of the cross current detection impedance Z _C does not affect the distribution system (for example, line voltage does not change) when the cross current detection impedance Z _C is inserted (when the switch (20-7) is closed), for example, in the rear. Set to a value several tens to several hundreds times the impedance Z _A and Z _B.

The cross current detection impedances Z _C corresponding to the respective loop point switches SS ₂₀ and SS ₃₀ may be inserted at the same time, but they should be shifted in time so that they do not overlap. The more accurate the actual cross current value can be predicted. In any case, these insertion controls are performed by, for example, a command from the master station (40) or a clock provided in the slave station.

In addition, the master station (40) detects and selects a case where the actual cross current value is small during one week, one day, or throughout the year, and switches on the corresponding switch in that case. May be.

Although the communication line is used as the data transmission path between the master station and the slave station in the above embodiment, other data transmission means may be used. Also, a method of directly inserting a transformer between both sides of the loop switch as the differential voltage detection for detecting the cross current was shown. For example, a transformer is provided between each line on both sides, and a secondary side of the transformer is provided. The differential voltage may be detected by, and regardless of the detecting means, the same effect can be obtained in the method of detecting the differential voltage between both sides. In addition, as the optimum selection method of the loop point switch, the protection coordination with the distribution substation, the cutoff capacity of the section switch, the interchange capacity margin, and the one with a small cross current value were checked. Therefore, even if these check contents are changed, the same effect can be obtained if the purpose is the same.

Further, even if a semiconductor switch such as a thyristor is used as the division switch and the loop point switch, the same effect as that of the above-described embodiment can be obtained.

〔The invention's effect〕

As described above, according to the present invention, for each of the loop point switches in the open state among the plurality of loop point switches, the cross current that flows when the loop switch is switched to the closed state is predicted, and the cross current is predicted. Since the loop point switch with the smallest switch is selected and switched to the closed state, the distribution system can be switched without a blackout in a certain section, and the influence of cross current generated at the time of switching can be minimized. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a block diagram showing a distribution line loop switching device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a block diagram of the slave station shown in FIG. 1, and FIG. 3 shows the principle of cross current detection. FIG. 4 is a block diagram and FIG. 4 is a distribution system diagram for explaining the conventional technique. AS / S, BS / S, CS / S are distribution substations, (1) (2) (3) are distribution substations AS / S, BS / S, CS / S busbars, SS ₁₁ , SS ₁₂ , SS ₂₁ , S
S ₂₂ and SS ₃₁ are sectional switches, SS ₂₀ and SS ₃₀ are loop point switches,
(11) (12) (20) (21) (22) (30) (31) are slave stations,
(11-1) (11-2), (12-1) (12-2), (21-
1) (21-2), (22-1) (22-2), (31-1)
(31-2) is a section switch (11) (12) (21) (22) (3
Drop-in wire for pulling in the voltage on both sides of 1) to the slave station, (20
-1) and (20-2), (30-1) and (30-2) are drop lines for pulling the voltage on both sides of the loop point switches (20) and (30) to the slave station, and (11-3 ), (12-3), (21-3),
(22-3) and (31-3) are sectional switches (11) (12) (2
1) Control line for controlling opening / closing of (22) (31), (20-3) (3
0-3) is a control line for controlling opening / closing of the loop point switches (20) (30), (40) is a master station, (50) is a communication line, (20-4) is a switch, and (20-5) is Control line for controlling the switch (20-4), (20-6) is a transformer for differential voltage detection, (20-7)
Is a switch, (20-8) is a control line for controlling the switch (20-7), (20-9) is a current transformer for cross current detection, (20-10)
Is a control circuit and Z _C is a cross current detection impedance. In the drawings, the same reference numerals indicate the same or corresponding parts.

Front page continuation (72) Inventor Toshinobu Ebisaka 1-2-2 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Inside Mitsubishi Electric Corporation Control Works (72) Keiji Isahaya 1 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo No. 1-2, Mitsubishi Electric Corporation Control Works (56) Reference JP-A-56-86025 (JP, A)

Claims (1)

[Claims] 1. In a distribution system in which a plurality of loop point switches are connected to a distribution line that links a plurality of distribution substations, the switching of each loop point switch is controlled to perform interchange power transmission. In the power interchange system of the distribution system, the differential voltage between the voltages applied to both ends of the loop point switch in the open state among the plurality of loop point switches and the cross current detection in parallel with the loop point switch. A slave station that detects a current flowing through the impedance when the impedance is inserted and predicts a cross current that flows when the loop point switch is switched to the closed state based on the voltage difference and the current flowing through the impedance; When switching any of the open loop point switches among the above loop point switches to the closed state, select the loop point switch with the smallest cross current predicted by the slave station. And, power interchange system of the distribution system, characterized in that the selected loop point switch is provided a master station for shifting to the closed state with respect to said child station.