JPH11285173A - Switch control for distributed power supply and distribution system with the distributed power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restart parallel feeding from a distributing substation and distributed power supply, without power failures after the recovery from an accident. SOLUTION: A switch (SW2) 15 which is mounted on a distribution line 13, fed from a distributing substation 11 and distributed power supply 19 in parallel, is opened, if an accident occurs in the distribution line 13 (at F-point) and re-inputted after the recovery from the accident. In the re-inputting, a master station 16 controls other switches 15, so that feeding is conducted from the distributing substation 11 to one side of the switch (SW2) 15, and from a distributed power supply 19 to the other side of the switch (SW2) 15, and a slave station 17 computes the difference in voltage frequencies or the like between both the sides of the switch 15, and sends it to a dedicated slave station 19d through the master station 16. The dedicated slave station 19d controls a synchronizing apparatus 19e, so as to eliminate the received difference in the frequencies or the like, upon the fimshing of controlling synchronization, communicates to that effect to the master station 16. The master station 16, as a result, sends a command to the slave station 17 to re-input the switch 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch control method and a distributed power supply for a distribution system in which a plurality of switches are supplied in parallel from a distribution substation and a distributed power supply to a distribution line in which a plurality of switches are separated in series. Related to the distribution system.

[0002]

2. Description of the Related Art A distribution system that does not cause a power failure in a healthy section even when an accident occurs in a distribution line is extremely important.
The conventional example will be described with reference to FIG.
Is a circuit breaker (CB) 4 connected to the bus 2 in the distribution substation 1 for connecting or disconnecting the bus 2 and the distribution line 3, and is interposed in series at a predetermined interval on the distribution line 3. A plurality of switches (SW1 to SW5) 5. The master station 6 installed in the business office E is connected to a plurality of slave stations (S1 to S5) 7 arranged adjacent to each switch 5 by a communication line 8, and the switch is connected to the slave station 7. The command for executing the monitoring / opening / closing control of the state of 5 is output.

[0003] On the other hand, the slave station 7 opens the switch 5 when detecting the occurrence of an accident based on a signal from a voltage / current detector (not shown) incorporated in the switch 5, and at the same time, the slave station 7 It is configured to communicate that an accident has occurred, and to switch on the switch 5 again upon receiving a command from the master station after the accident has been recovered.

The distribution system S is provided with a distributed power supply 9 for supplying power to the distribution line 3 in parallel with the distribution substation 1. The distributed power supply 9 includes a power supply 9a and a circuit breaker 9b, monitors a voltage on the distribution line 3 side of the circuit breaker 9b, and adjusts the voltage and the voltage generated by itself to be synchronized in frequency and phase. A synchronization adjusting device (not shown) is provided, and the power supply is started by closing the circuit breaker 9b in a state where the frequency and phase of the voltage are synchronized.

In the distribution system S, when a ground fault occurs at the point F, S1 and S2 of the slave stations 7 open the switches SW1 and SW2 to separate the fault zone L2.
Therefore, power is supplied from the distribution substation 1 to the section L1, which is a healthy section, and power is continuously supplied from the distributed power supply 9 to the sections L3, L4, L5,. Is to be prevented.

[0006]

However, in the above system, the accident is recovered and the distribution system is restored to its original state (standard state in which power supply from the distribution substation 1 and parallel power supply from the distributed power supply 9 are performed). To return to
W1 is turned on, and then the circuit breaker 9b of the distributed power supply 9 is opened to stop the power supply from the distributed power supply 9 once. Then, the switch SW2 is turned on, and then the synchronization is adjusted by the synchronization adjustment device of the distributed power supply 9. Since the switch 9b needs to be turned on later, there is a problem that a power failure occurs in the sections L3, L4, L5, etc. as a result. This operation is performed because the frequency difference and the phase difference occur between the voltage in the power supply of the distribution substation 1 and the distributed power supply 9 during the open period of the switch SW2. This is because, when the switch SW2 is closed, an overcurrent may flow to adversely affect the device.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to address the above problems, and has as its object to provide a distribution substation and a distribution line with a distributed power supply immediately without the occurrence of a power failure after the accident has been restored. In parallel power supply.

A feature of the present invention to achieve the above object is to provide a distribution line that is supplied in parallel from a distribution substation and a distributed power source, a distribution line that is interposed in the distribution line, and that is opened when an accident occurs in the distribution line. In the switchgear control method for a distribution system having a switchgear re-opened after an accident is recovered, the switchgear is supplied to one side of the switchgear from the distribution substation and distributed to the other side of the switchgear. Power from the power supply, detects the frequency difference and phase difference of the voltage on both sides of the switch, adjusts and controls the distributed power supply to eliminate the frequency difference and phase difference, and performs it at the time when this synchronization control ends. I did it.

According to this feature, it is possible to create a state in which there is no frequency difference or phase difference between the voltages on both sides of the switch opened by the accident, so that no excessive current is generated. It becomes possible to input. Therefore, since it is not necessary to temporarily shut down the distributed power supply, it is possible to restart the parallel power supply to the distribution line by the distribution substation and the distributed power supply without causing a power failure after the restoration of the accident.

It is to be noted that the control method having the above-mentioned feature causes a slave station arranged adjacent to the switch to detect a frequency difference and a phase difference of the voltage, and a dedicated slave station arranged adjacent to the distributed power supply to the slave station. This can be achieved by receiving the detected frequency difference and phase difference through communication, and executing the adjustment control of the distributed power supply based on the frequency difference and phase difference.

Another feature of the present invention is that a distribution line is supplied in parallel from a distribution substation and a distributed power source, a plurality of switches interposed at predetermined intervals in the distribution line, and A substation that monitors or controls switching based on a command sent from the station via a communication line, and that exists in the same section when an accident occurs in the distribution line between the distribution substation and the distributed power supply In a power distribution system having a distributed power supply configured to open at least one of the slave stations, a dedicated station connected to the master station via a communication line and performing communication with the master station via the communication line is provided. Installing a slave station adjacent to the distributed power source,
The dedicated slave station has a means and a frequency for adjusting the frequency and phase of the distributed power supply so as to eliminate the frequency difference and the phase difference according to predetermined information related to the frequency difference and the phase difference communicated via the communication line. Means for communicating an adjustment end signal to the master station at the end of phase adjustment, wherein the slave station has
Means for detecting voltages on the distribution substation side and the distributed power supply side of the switchgear opened by the occurrence of the accident and calculating the frequency difference and phase difference between the two voltages, means for communicating the calculation result to the master station, And means for closing the switch based on a predetermined command communicated from the master station, and further comprising means for communicating the calculation result communicated from the slave station to the dedicated slave station as predetermined information. Means for communicating the adjustment end signal from the dedicated slave station to the slave station as a predetermined command, and turning on the switch in a state where the synchronization adjustment of the phase and frequency between the voltages on both sides of the switch has been completed. It is to be configured.

According to another feature of the present invention, the slave station detects voltages on the distribution substation side and the distributed power supply side of the switch opened by the occurrence of the accident, respectively, and calculates a frequency difference and a phase difference between the two voltages. To communicate with the master station. The master station communicates this to a dedicated slave station located adjacent to the distributed power source. The dedicated slave station adjusts the frequency and phase of the distributed power supply based on the frequency difference and phase difference calculated by the slave station communicated via the master station, and returns an adjustment end signal to the master station when the adjustment is completed. The master station communicates a command for turning on the switch to the slave station based on the adjustment signal. Therefore, a distribution system having another feature of the present invention can restart parallel power supply from a distribution substation and a distributed power supply after a recovery from an accident without causing a power outage.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A distribution system (distribution system) 10 according to an embodiment of the present invention shown in FIG.
A circuit breaker (CB) 14 connected to the bus 12 in the power transmission line 1 to control the power supply from the distribution substation 11 to the distribution line 13 by connecting or disconnecting the bus 12 and the distribution line 13, and a predetermined interval on the distribution line 13. And a plurality of switches interposed in series (SW1 to SW1)
SW5) 15, master station 16 installed in the sales office, master station 1
6 via a communication line 18 and each switch 1
5 are connected to the point A of the distribution line 3 via the connection lines 19b and connected to the slave stations (S1 to S5) 17 arranged adjacent to the substation 5 and feed the distribution line 3 in parallel (simultaneously) with the distribution substation 11. And a distributed power supply 19.

As shown in detail in FIG. 2, each slave station 17 includes a first detector 17a for detecting a voltage on the distribution substation 11 side of the switch 15 (point 15a), and a second detector 17a for the switch 15. Side (distributed power supply 1 for switches SW1 to SW3)
A multiplexer 17c connected to a second detector 17b for detecting a voltage on the ninth side, that is, a point 15b), an AD converter 17d for AD-converting a signal from the multiplexer 17c, and various signals by inputting signals from the AD converter 17d. The CPU 17e for executing the operation, the data communication circuit 17 for taking in the signal on the communication line 18 to the CPU 17e or transmitting the operation result of the CPU 17e to the communication line 18.
f and the signal from the CPU 17e to amplify the switch 15
And an output circuit 17g that opens and closes. Slave station 17
Performs monitoring and switching control of the state of the switch 15 in response to a command from the master station 16 received via the communication line 18,
Also, predetermined information (such as accident information) is transmitted to the master station via the communication line 18.

The distributed power supply 19 shown in FIG. 1 includes a power supply 19a such as a generator and a battery, and a circuit breaker 19 interposed in series with a connection line 19b connecting the power supply 19a and the point A of the distribution line.
c, a synchronization adjuster 19e that monitors the voltage on the distribution line 3 side (point A side) of the circuit breaker 19c and adjusts the voltage and the voltage generated by the power supply 19a so that they are synchronized in phase and frequency. And a dedicated slave station 19d for giving an instruction to the synchronization adjusting device 19e. The dedicated slave station 19d is connected to the master station 16 via the communication line 20, and has a microcomputer similar to the slave station 17 in the internal configuration.
It includes a communication circuit and a control circuit including an input / output circuit and the like.

Next, the distribution system 1 configured as described above
The operation of the distribution system 10 will be described. In the distribution system 10, the circuit breaker (CB) 14 of the distribution substation 11 is normally turned on to supply power to the distribution line 13. At the same time, the distributed power supply 19 is operated (in parallel) and the circuit breaker 19c is turned on to supply power to the distribution line 13.

In this state, for example, F
When an accident (ground fault, short circuit accident) occurs at a point, the slave station S
The slave stations S1 and S2 alone (or in cooperation with the master station 16) switch based on currents and voltages detected by sensors (not shown) built in the switch 15 for the slave stations 1 and S2. Recognizing that an accident has occurred between SW1 and switch SW2 (hereinafter, referred to as section L2, and other sections are also shown), switches SW1 and SW2 are opened to open accident section L2 to another health level. Separate from the section. Therefore, thereafter, power supply from the distribution substation 11 is continued in the section L1, and power supply is continued from the distributed power supply 19 in the sections L3, L4, L5,.

Although the above-described method of detecting an accident section (a method of recognizing in which section an accident has occurred) is well known, for example, “each slave station 17 may be configured to determine the zero-phase voltage, zero-phase current, The load current is detected, and based on these, the fault point is determined for each switch.
5, the power supply side or the load side is detected and stored.
6 obtains the stored information of these slave stations 17 through communication and specifies the accident section.

When the accident is recovered, the master station 16 gives an instruction to the slave station S1 via the communication line 18 (by an operator giving an instruction to the master station, for example), and the slave station S1 operates the switch according to the instruction. Turn on SW1 again. When the switch SW1 is turned on, the switch SW2 is connected to the distribution substation 11 (point 15a in FIG. 2).
Side), a voltage based on power supply from the distribution substation 11 is applied. Further, the switch SW2 is connected to the distributed power supply 19 (point 1).
5b), a voltage based on power supply from the distributed power supply 19 is applied. Therefore, the master station 16 is located on both sides of the switch SW2 (point 15a which is one end of the switch SW2) with respect to the slave station S2.
Is instructed to calculate the frequency difference and phase difference of the voltage at the other end (both ends of the point 15b).

On the other hand, the CPU 17e of the slave station S2 executes the program shown in the flow chart of FIG. 3 from the step 300 at predetermined time intervals, and upon receiving the above-described instruction from the master station 16, the instruction from the master station 16 is issued. Is determined to be “Yes” in step 305 for determining the presence / absence of

The CPU 17e inputs the voltage generated on both sides of the switch SW2 in step 310 from the first and second detectors 17a and 17b via the multiplexer 17C and the AD converter 17d. Then, step 3
Proceed to step 15 to perform a Fourier transform on each input voltage.
At 0, the frequency and phase of each input voltage are calculated based on the Fourier transform result.

Subsequently, the CPU 17e proceeds to step 325, calculates the frequency difference and phase difference between these two voltages, converts the calculation result into communication data in the next step 330, and proceeds to step 335 to convert the communication data. The signal is output to the communication line 18 and transmitted to the master station 16. After that, CPU1
7e proceeds to step 340, and determines whether or not an adjustment end signal (or a switch closing signal) has been received from the master station 16. At this point, since the adjustment end signal has not been transmitted from the master station 16, the process returns to step 310 and the above operation is repeated.

Referring again to FIG. 1, the master station 16 transmits the information on the frequency difference and phase difference of the voltage transmitted from the slave station S2 to the dedicated slave station 19d of the distributed power supply 19 via the communication line 2.
Send via 0. Dedicated slave station 19 that has received this information
d is a power source (generator, inverter) so that the received frequency difference and phase difference are small (the difference is eliminated).
Issues a command to the synchronization adjustment device 19e to control the device 19a,
The synchronization adjustment device 19e starts the synchronization adjustment.

At this time, since the synchronization adjustment control has just started, the dedicated slave station 19d does not send an adjustment end signal to the master station 16. Therefore, the slave station S2 determines “No” in step 340 shown in FIG. 3 described above, and repeats steps 310 to 335 to periodically transmit information on the frequency difference and the phase difference to the master station 16. Accordingly, the master station 16 periodically transmits information on the frequency difference and the phase difference to the dedicated slave station 19d.

After a predetermined time has elapsed, the synchronization adjusting device 19
When e completes the synchronization, the synchronization adjustment device 19e outputs a synchronization completion signal to the dedicated slave station 19d, and the dedicated slave station 19d receiving the signal sends a synchronization adjustment end signal to the master station 16 via the communication line 20. . The master station 16 sends this synchronization adjustment end signal to the slave station S2.

The CP of the slave station S2 that has received the synchronization adjustment end signal
U17e determines "Yes" in step 340 of the flowchart in FIG. 3, proceeds to step 345, and turns on the switch SW2 again. In this way, the distribution system returns to the standard state, and the power supply from the distribution substation 11 and the distributed power supply 19 over the entire section of the distribution line 13 is resumed after the restoration of the accident without a power failure.

The case where an accident occurs at the point F in the section L2 has been described above. However, the power distribution system (distribution system) 10 of the present embodiment is provided in the section L1 or the section L3.
The same operation is performed when an accident occurs in (ie, any section between the distribution substation 11 and the distributed power supply 19). For example, when an accident occurs in the section L1, the slave station S1, the master station 16, and the dedicated slave station 19d communicate with each other to open and close the switch S.
After eliminating the voltage frequency difference and the phase difference between both ends of W1, the switch SW1 is turned on again. Further, when an accident occurs in the section L3, the slave station S3, the master station 16 and the dedicated slave station 19
d communicates and eliminates the voltage frequency and the phase difference between both ends of the switch SW3, and then turns on the switch SW3 again.

In the above-described embodiment, when the accident at the point F is restored, the switch SW1 is turned on first, and the switch SW2 is turned on after the synchronization adjustment. However, the switch SW2 is turned on first, and the switch SW2 is turned on after the synchronization adjustment. SW1 may be turned on. That is, the feature of the present invention is that when the switch 15 that is finally in a state where the power supply from the distribution substation 11 and the power supply from the distributed power supply 19 are superimposed is turned on, both sides of the switch 15 ( Since the function is to eliminate the voltage frequency difference and the phase difference at both ends), various methods can be adopted for the control of the other switches 15 until the state is reached. is there.

Further, in the above embodiment, the master station 16 which has received the synchronization adjustment end signal from the dedicated slave station 19d immediately sends a synchronization adjustment end signal to the slave station S2 and turns on the switch SW2. After the master station 16 receives the synchronization adjustment end signal, it waits for confirmation by the operator, and the operator sets the switch S
When a signal for permitting re-input of W2 is input, the slave station S
Synchronization adjustment end signal (switch open signal in this case)
May be sent.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an embodiment according to a distribution system of the present invention.

FIG. 2 is an internal circuit diagram of the slave station shown in FIG.

FIG. 3 is a flowchart showing a program executed by a CPU of a slave station shown in FIG. 2;

FIG. 4 is a schematic diagram of a conventional power distribution system.

[Explanation of symbols]

11 ... distribution substation, 12 ... busbar, 13 ... distribution line, 14 ...
Circuit breaker, 15 ... Switch, 16 ... Master station, 17 ... Slave station, 18
... Communication line, 19 ... Distributed power supply, 19a ... Power supply, 19d ...
Dedicated slave station, 19e: Synchronization adjustment device, 20: Communication line

Claims (3)

[Claims] 1. A distribution line which is fed in parallel from a distribution substation and a distributed power source, and a switch which is interposed in the distribution line and which is opened when an accident occurs in the distribution line and which is turned on again after the accident is recovered. In the method of controlling a switch of a power distribution system, the power supply of the switch is supplied from the distribution substation to one side of the switch, and the distributed power supply is supplied to the other side of the switch. Then, the frequency difference and the phase difference of the voltage on both sides of the switch are detected, and the distributed power supply is adjusted and controlled so as to eliminate the frequency difference and the phase difference. A switch control method for a distribution system characterized by the above-mentioned. 2. The switch control method for a distribution system according to claim 1, wherein a slave station disposed adjacent to the switch detects a frequency difference and a phase difference of the voltage, and is disposed adjacent to the distributed power supply. A switch for the distribution system, wherein the dedicated slave station receives the frequency difference and the phase difference detected by the slave station by communication, and executes the adjustment control of the distributed power supply based on the frequency difference and the phase difference. Control method. 3. A distribution line that is fed in parallel from a distribution substation and a distributed power source, a plurality of switches interposed at predetermined intervals in the distribution line, and a communication line connecting the switch to a master station. And a slave station that monitors or controls switching based on a command sent through the switch, and the switch that is present in the same section when an accident occurs in the distribution line between the distribution substation and the distributed power supply In a distribution system including a distributed power supply configured to open at least one of the slave stations, the slave station is connected via a communication line to communicate with the master station via the communication line. A dedicated slave station to perform is installed adjacent to the distributed power source, and the dedicated slave station performs the same frequency difference and phase difference according to predetermined information regarding the frequency difference and phase difference communicated via the communication line. Frequency of the distributed power source so as to eliminate Means for adjusting the phase and means for communicating an adjustment end signal to the master station at the end of the synchronization adjustment, wherein the slave station has the switchgear side of the switch, which has been opened due to an accident, and A means for detecting the voltage on the distributed power supply side and calculating the frequency difference and the phase difference between the two voltages; a means for communicating the calculation result to the master station; and a predetermined command communicated from the master station. Means for turning on the switch, wherein the master station communicates the calculation result communicated from the slave station to the dedicated slave station as the predetermined information, and finishes adjustment from the dedicated slave station. Means for communicating a signal to the slave station as the predetermined command, wherein the synchronous adjustment of the phase and frequency between the voltages of the distribution substation side and the distributed power supply side of the switch has been completed. Make sure that the switch is turned on. And a distribution system having a distributed power supply.