JPH10341534A - Non-utility substation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-utility substation which can ensue supply power to the most important load at the time of instantaneous voltage drop of a commercial power source. SOLUTION: A non-utility substation, which is provided with an instantaneous voltage drop countermeasure device and a standby generator, involves important loads ranked further into the most important load 10-1, and an important load 10-2. The combinations of a plurality of pairs of instantaneous voltage drop countermeasure devices 8-1, 8-2, and system linking breakers 7-1, 7-2, and an intermediate bus-bar 13 are formed between a generator side bus-bar 6 and a commercial power source side bus-bar 5. The most important load 10-1 is connected to the generator side bus-bar 6, the important load 10-2 to the intermediate bus-bar 13, and a general load 12 to the commercial power source side bus-bar 5, respectively. At the time of instantaneous voltage drop of the commercial power source 1, bus-bar selection is conducted according to the output of power generation of the standby generator 2 at that time, thus it is possible to always ensure the supply power to the most important load 10-1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a private substation equipped with a service generator, in which an instantaneous voltage drop countermeasure device is introduced to reduce the influence of a momentary voltage drop of a commercial power supply on an important load.

[0002]

2. Description of the Related Art FIG. 3 shows an example of the configuration of a private substation incorporating an instantaneous voltage drop countermeasure device. In the figure, 1 is a commercial power supply, 2
Is a service generator (one or more), 3 is a power receiving circuit breaker, 4 is a generator circuit breaker, 5 is a commercial power supply side bus, and 6 is a generator side bus. Commercial power bus 5 and generator bus 6
Are connected to each other by a circuit-interconnect circuit breaker 7 and an instantaneous voltage drop countermeasure device 8. An important load 10 is connected to the generator-side bus 6 via a feeder circuit breaker 9. A feeder circuit breaker 1 is connected to the bus 5 on the commercial power supply side.
The general load 12 is connected via the power supply 1.

The instantaneous voltage drop countermeasure device 8 comprises a thyristor switch, a high-speed voltage detection circuit, and the like. The thyristor switch is turned off when the instantaneous voltage drop is detected at a high speed, and turned on after the circuit-interconnect circuit breaker 7 is opened. State (standby state).

In FIG. 3, when an instantaneous voltage drop occurs in the commercial power supply 1, an instantaneous voltage drop countermeasure device 8 operates,
The grid connection between the commercial power supply 1 and the service generator 2 is released at a high speed (within one cycle). Then, the circuit breaker 7 for grid connection
Is tripped. Thereby, the influence of the instantaneous voltage drop on the important load 10 is reduced.

After the circuit breaker 7 is opened, the thyristor switch of the instantaneous voltage drop countermeasure device 8 is turned on, and waits for the commercial power source 1 to recover power. At the time of power restoration, a control command is given to the existing generator automatic synchronization input device, and the system is returned to the normal state with the synchronization of the system-interconnection circuit breaker 7.

[0006]

As described above, by introducing the instantaneous voltage drop countermeasure device 8, when the instantaneous voltage drop of the commercial power supply 1 occurs, the grid connection is released at a high speed, and the influence on the important load 10 is reduced. When the power generation output of the service generator 2 at the time of disconnection is smaller than the total capacity of the important load 10, the influence on the important load 10 cannot be avoided even by the high-speed disconnection. In this case, the service generator 2 may be stopped.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a private substation capable of securing power supply to a most important load even when the instantaneous voltage of a commercial power supply drops.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a private substation equipped with a service generator, which incorporates an instantaneous voltage drop countermeasure, and divides important loads into a plurality of ranks, and assigns the most important load to other important loads. On the other hand, between the generator-side bus and the commercial power supply-side bus, a combination of a plurality of sets of instantaneous voltage drop countermeasure devices and a system interconnection circuit breaker, and an intermediate bus are provided.
The most important load is connected to the generator bus, the important load is connected to the intermediate bus, and the general load is connected to the commercial power bus. Accordingly, a bus selection that always secures the power supply to the most important load is performed.

[0009]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a commercial power supply, 2 is a regular generator (for example, 2
(Table), 3 is a power receiving circuit breaker, 4 is a generator circuit breaker, 5 is a commercial power supply side bus, and 6 is a generator side bus. Between the generator-side bus 6 and the commercial power supply-side bus 5, there are two sets of instantaneous voltage drop countermeasure devices and a system interconnection circuit breaker (instantaneous voltage drop countermeasure device 8-
1 and system-interconnection circuit breaker 7-1, instantaneous voltage drop countermeasure device 8
-2 and the circuit-interconnect circuit breaker 7-2) via the intermediate bus 13. The most important load 10-1 is connected to the generator-side bus 6 via a feeder circuit breaker 9-1. An important load 10-2 is connected to the intermediate bus 13 via a feeder circuit breaker 9-2. The most important load 10-1 and the most important load 10-2 are obtained by ranking the conventional important loads 10. A general load 12 is connected to the commercial power supply side bus 5 via a feeder circuit breaker 11.
When ranking the loads, consider the relationship of generator maximum output> most important load + important load generator operation minimum output> most important load. In this embodiment, the maximum operation output of the generator is the output when the two service generators 2 are operating,
The operation minimum output of the generator is an output when one service generator 2 is operating (when one unit is stopped).

Reference numeral 14 denotes a load selection control unit which detects the output voltage and the generated power of the two service generators 2, determines whether the number of active generators is one or two from the detection result, and determines the number of the generators. , A bus that maintains the connection with the service generator 2 is selected, and a control command to turn off is selected, and the instantaneous voltage drop countermeasure device 8-
1, 8-2. That is, when an instantaneous voltage drop of the commercial power supply 1 occurs at the maximum output of the generator operation, a control command is given only to the instantaneous voltage drop countermeasure device 8-2 close to the commercial power supply side, and the generator side is connected to the bus for maintaining the connection. Bus 6 and Intermediate Bus 1
Select 3. If an instantaneous voltage drop of the commercial power supply 1 occurs at the minimum operation output of the generator, a control command is given to the instantaneous voltage drop countermeasure device 8-1 to select only the generator-side bus 6 as the bus for maintaining connection. I do.

With this configuration, when an instantaneous voltage drop of the commercial power supply 1 occurs, the instantaneous voltage drop countermeasures 8-1 and 8-2 detect the instantaneous voltage drop at high speed. The operation status of the service generator 2 at this time is accurately grasped by the load selection control unit 14. In the case of the operation maximum output of the operation of all the units (two units), the off control command is given only to the instantaneous voltage drop countermeasure device 8-2 close to the commercial power supply 1 in order to disconnect only the commercial power supply side bus 5. As a result, the thyristor switch of the instantaneous voltage drop countermeasure device 8-2 is turned off, and subsequently, the same group of system-interconnect circuit breakers 7-2 is tripped. In this state, the intermediate bus 13 is in a connected state, and power supply to not only the most important load 10-1 but also the important load 10-2 is continued.

If the instantaneous voltage drop of the commercial power supply 1 occurs at the time of the minimum operation of the generator (one unit is stopped), the load selection control unit 14 gives an off-control command to the instantaneous voltage drop countermeasure device 8-1. . Thereby, the thyristor switch of the instantaneous voltage drop countermeasure device 8-1 is turned off, and the corresponding system interconnection breaker 7-1 is subsequently tripped. In this state, the commercial power supply including the commercial power supply side bus 5 and the intermediate bus 13 is disconnected, and the most important load 10−
The power supply from the service generator 2 is continued for only one.

The determination of the operation state of the service generator 2 depends on the control flow shown in FIG. That is, first, it is determined whether or not the instantaneous voltage drop of the commercial power supply 1 has occurred (Step S).
1) If No, the same judgment is repeated. When an instantaneous voltage drop occurs (when Yes), it is determined whether or not there are two generators (S2).
2 is issued (S3), and if No, an off-control command is issued to the instantaneous voltage drop countermeasure device 8-1 (S3).
4).

In the above description, two service generators 2 are used. However, three or more service generators 2 or one having a large capacity may be used. Similarly, the number of circuit-interruption circuit breakers and instantaneous voltage drop countermeasures between the commercial power supply-side bus 5 and the service generator-side bus 6 is arbitrary, and is increased or decreased according to the rank number of the important load. The number of intermediate buses will be increased or decreased similarly.

[0015]

As described above, according to the present invention, a plurality of combinations of a circuit-interruption circuit breaker and an instantaneous voltage drop countermeasure device are provided between a commercial power supply-side bus and a service generator-side bus. An intermediate bus is provided between pairs, and a general load is applied to each bus.
The important load and the most important load are connected, and when the instantaneous voltage of the commercial power supply drops, the load selection (bus selection) according to the generator output is performed. Therefore, at least the power supply to the most important load is always secured. And can greatly contribute to improving the reliability of power supply.

[Brief description of the drawings]

FIG. 1 is a single-wire connection diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart for grasping the generator operation status of one embodiment.

FIG. 3 is a single-line connection diagram showing a conventional configuration example of a private substation incorporating an instantaneous voltage drop countermeasure device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Commercial power supply 2 ... Regular generator 5 ... Commercial power supply side bus 6 ... Generator side bus 7 ... Circuit breaker 8 ... General load 13 ... Intermediate bus 14 ... Load selection control unit

Claims (1)

[Claims] Claims 1. In a private substation equipped with a service generator in which an instantaneous voltage drop countermeasure device is introduced, important loads are divided into a plurality of ranks, and the most important load and other important loads are determined. Between the bus and the commercial power supply bus, a combination of multiple sets of instantaneous voltage drop countermeasure devices and circuit breakers and an intermediate bus are provided, and the most important load is placed on the generator bus and important on the intermediate bus. Connect the load and the general load to the commercial power bus, and select a bus that always secures the power supply to the most important load according to the power output of the service generator at the time of instantaneous voltage drop of the commercial power. Private substation characterized by doing it.