JPH01148075A - Inverter equipment - Google Patents

Abstract

PURPOSE:To make a phase synchronizing signal of an inverter redundant without adding any new equipment by obtaining the phase synchronizing signal of the inverter via an instrument transformer connected with a power source supplying power through a bus, when the phase synchronizing signal is lost or becomes abnormal. CONSTITUTION:A switch 20C is normally opened and a switch 20D is normally closed. A phase synchronizing signal 10 from an instrument grounded transformer 4A is supplied as a phase syncronizing signal for a phase adjuster 21 of a rectifier 16. In this case, when a phase signal selector 19 detects the abnormality of the signal 10, the selector 19 immediately closes the switch 20C and opens the switch 20D. Keying signals 14 and 13 from breakers 6A and 6C of a station service transformer 3A are respectively inputted to a bus switching judging device 18 for judging which of the house transformer 3A or starting transformer 3B an inverter equipment 1 receives power through the bus from. Then, a keying command is given to switches 20A, 20B so that the corresponding signal out of phase synchronizing signals 11, 12 from respective buses is permitted to pass through.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an inverter device that is used in a switching bus and is supplied with a phase synchronization signal from the bus.

[Prior Art] A conventional inverter device is illustrated in FIG. AC power on the bus bar 2 enters the inverter device 1 via the circuit breaker 6. This alternating current is transferred to the input transformer 15 within the inverter device 1.
After being stepped down by A, it is converted to direct current by a rectifier 16, and this direct current is again converted to variable frequency alternating current by an inverter 17, and then boosted by an output transformer 15B and output. The alternating current output from the inverter device 1 is supplied to the electric motor 9, which is a load.

By the way, the rectifier 16 in the inverter device 1 requires a phase synchronized signal of the input voltage as a gate signal. A method for extracting this phase synchronization signal is disclosed in Japanese Patent Application Laid-Open No. 59-139.
As shown in FIG. 3 of Japanese Patent No. 891, it is known that the inverter device is taken out from the in-house bus bar connected to the inverter device. In the example of the above-mentioned publication, the voltage taken out from the station bus is stepped down by the instrument transformer 4A, and the phase adjuster 21 inputs a gate signal to the rectifier 16 through the pulse amplifier 22 using this signal as a reference. The phase synchronization signal is used as a reference phase to output the gate signal of the thyristor that constitutes the rectifier 16. If the phase synchronization signal is lost, the rectifier will not be able to output the gate signal at the specified phase. Operation becomes impossible due to voltage control.

As described above, conventionally, the phase synchronization signal necessary to control the inverter device was extracted from the station bus to which the inverter is connected.

[Problems to be Solved by the Invention] The above-mentioned conventional technology does not give consideration to redundancy of the phase synchronization signal of the inverter. For example, inverters are used to drive large variable-speed motors that play an important role in power plants, such as motors for recirculation pumps in boiling water nuclear power plants. If this is the case, the electric motor will stop due to the inverter stopping, which will impede the operation of the power plant. Therefore, the inverter device is required to operate normally without stopping.

For normal operation of the inverter device, it is necessary that the phase synchronization signal of the inverter be accurately input to the inverter device. From this point of view, simply obtaining a phase synchronization signal from one place as in the past has problems with its reliability.
Redundancy is desired.

As a method to make the phase synchronization signal redundant, two voltage transformers are installed on the busbar to which the inverter device is connected.
There is a method of extracting the phase synchronization signal from multiple locations, but this method requires additional equipment and is not economical.

An object of the present invention is to make inverter phase synchronization signals redundant without adding new equipment.

c. Means for Solving Problems] The above object is to provide an instrument in which the bus to which the inverter is connected is supplied with power from either of two power sources, and the phase synchronization signal of the inverter is connected from the bus to the bus. In an inverter device in which the power is supplied through a potential transformer and each of the two power supplies is connected to a potential transformer, when the phase synchronization signal is lost or becomes abnormal, power is supplied to the bus. This is achieved by arranging the inverter's phase synchronization signal to be obtained via a voltage transformer connected to the power supply.

[Function] Normally, the signal from the voltage transformer connected to the bus to which the inverter is connected is used as the inverter's phase synchronization signal, and when this phase synchronization signal is lost or abnormal, the signal from the voltage transformer connected to the bus to which the inverter is connected is used. The phase signal from the potential transformer that is currently connected to the power supply is used as the phase synchronization signal for the inverter. As a result, the phase synchronization signal for inverter control is duplicated. The above-mentioned voltage transformer is a conventional voltage transformer, and there is no need to install a new voltage transformer for redundancy of the phase synchronization signal of the inverter.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a single line diagram showing one embodiment of the present invention.

This embodiment will be explained by taking as an example an inverter device that drives a motor for a recirculation pump of a nuclear reactor in a boiling water nuclear power plant.

In Figure 1, 1 is the inverter device, 2A, B is the bus bar, 3A
is the station transformer, 3B is the starting transformer, 4A and 4B are GPT
(Instrument grounding transformer), 5 is PT (Instrument transformer)
, 6A to 6E are circuit breakers, 7A to 7H are fuses, and 8 is a motor for a recirculation pump of the nuclear reactor. io is bus line 2A
Phase synchronization signal from GPT4A connected to 11
is a phase synchronization signal from GP74B connected to bus 2B, 12 is a phase synchronization signal from PT5 connected to station transformer 3A, and 13 is a communication breaker 6 between bus 2A and 2B.
C open/close signal (signal indicating whether the circuit breaker is open or closed), 14 is circuit breaker 6A connecting transformer 3A and bus 2A
shows the open/close signal.

When receiving power from an in-house generator, power is received from an in-house transformer 3A to bus 2A via circuit breaker 6A, and then to bus 2A.
Power is supplied from A to the inverter device 1 via the circuit breaker 6B. At this time, the circuit breaker 6C is open. In this case, the inverter device 1
By obtaining the close signal 14 of The phase synchronization signal 12 is used to make the phase synchronization signal redundant, and power is supplied to the recirculation pump motor 8.

When receiving power from an external power source when the in-house generator has not started yet, power is received from the starting transformer 3B to the bus 2B via the circuit breaker 6D, and the circuit breakers 6E and 6C are connected to the bus 2A from the bus 2B. Power is received through the bus bar 2A, and power is further supplied to the inverter device 1 from the bus bar 2A through the circuit breaker 6B.

At this time, the circuit breaker 6A remains open. In this case, the inverter device 1 receives the close signal 13 of the circuit breaker 6C from the circuit breaker 6C, so that the inverter device 1 closes the fuse 7C from the bus bar 2A.
, GPT 4A, phase synchronization signal 10 supplied via fuse 7E, and fuse 7F%GPT4 from bus 2B.
B, phase synchronization signal 11 supplied via fuse 7H
The phase synchronization signal is made redundant by using this, and power is supplied to the recirculation pump motor 8.

When the in-house generator starts generating electricity, close circuit breaker 6A,
The circuit breaker 6C is opened to perform bus switching.

FIG. 2 shows the above-mentioned inverter device 1, and shows an example of the configuration regarding switching of the above-mentioned phase synchronization signal. In FIG. 2, input transformer 15A, rectifier 16
, inverse converter 17, output transformer 15B1 phase adjuster 21,
The operation of the pulse amplifier 22 is the same as that shown in FIG. 3, and the other parts are devices for selectively controlling the phase synchronization signal to the phase adjuster 21 of the rectifier 16.

The operation of the device shown in FIG. 2 will be explained below.

The bus bar switching determination device 18 receives the switching signal 14 from the circuit breaker 6A of the station transformer 3A and the switching signal 13 from the circuit breaker 6C.
is input, the inverter device 1 determines which bus of the station transformer 3A or the starting transformer 3B is receiving power, and conducts the corresponding one of the phase synchronization signals 11 and 12 from each bus. Instructs the switches 20A and 20B to open and close as shown in FIG. For example, opening/closing signal 1 from circuit breaker 6A
4 is closed (that is, when the circuit breaker 6A is closed), the switch 20A is opened and the switch 20B is closed, and when the opening/closing signal 14 from the circuit breaker 6A is open, the switch 20 is closed.
A is closed and switch 20B is opened. By operating in this way, when power is being received from the station transformer 3A, the phase synchronization signal 12 from the PT5 is transmitted, and when power is being received from the starting transformer 3B, the phase synchronization signal 11 from the GP74B is transmitted. It will be adopted. In addition, at the time of busbar switching, although it is for a short time, two busbars 2A are used.

A situation occurs where power is received from 2B at the same time, but switch 20
A and 20B are interlocked so that only one of them is closed, so that the two phase synchronization signals it and 12 are not superimposed in the above operation.

The switch 20 is
In addition to the phase synchronization signal conducted from A or 20B, GP
There is a conventional phase synchronization signal 10 from T4A, and which signal is to be supplied as a phase synchronization signal to the phase adjuster 21 of the rectifier 16 is determined by the phase signal selection device 19 as follows.

Normally, the switch 20C is open and the switch 20D is closed, and the phase synchronization signal 10 is supplied to the phase adjuster 21 as a phase synchronization signal. At this time, the phase signal selection device 19
monitors the phase synchronization signal 10, and the phase synchronization signal 10
When an abnormality is detected, the switch 20C is immediately closed and the switch 20D is opened. In addition, the phase signal selection device 1
When the switch 9 determines that the phase synchronization signal 10 has returned to normal, the switch 20D is closed and the switch 20C is opened.

The above operation makes the phase synchronization signal of the phase adjuster 21 of the rectifier 16 redundant.

The above-mentioned instrument transformer has conventionally been used to output a phase signal from both buses in order to confirm that the two buses are in phase when switching between the bus from the station transformer and the bus from the starting transformer. This is an existing one. In the present invention, redundancy is achieved by using signals from these existing potential transformers as phase synchronization signals for the inverter, so there is no need to provide a new potential transformer.

Incidentally, although the above-mentioned embodiment has been described with reference to a boiling water nuclear power plant, the present invention is of course not limited to this.

[Effects of the Invention] According to the present invention, in order to control the inverter device, a plurality of phase synchronization signals can be obtained using an existing potential transformer, so that the phase synchronization signals of the inverter can be made redundant. , has the effect of improving the reliability of inverter equipment,
Moreover, since there is no need to newly install a voltage transformer, it is highly economical.

[Brief explanation of the drawing]

FIG. 1 is a single-line diagram showing an embodiment of the present invention, FIG. 2 is a control circuit diagram of an inverter device of the same embodiment, and FIG. 3 is a single-line diagram showing an example of the prior art. 1... Inverter device 2A, 2B... Bus bar 3A
...In-house transformer 3B...Starting transformer 4A, 4
B...GPT 5...PT6A~6E...
Circuit breakers 7A to 7H...Fuse 8...Recirculation pump motor 9...Electric motor 10.11.12...Phase synchronization signal 14...Opening/closing signal of circuit breaker 6A 15A, 15B... Transformer 16... Rectifier 17... Inverter 18.
・Bus bar switching judgment device 19 ・Phase signal selection device 20A to 200 ・Switch i, , , −, 1

Claims (1)

[Claims] The bus to which the inverter is connected is supplied with power from one of the two power sources, the phase synchronization signal of the inverter is supplied from the bus through the voltage transformer connected to the bus, and the two power sources are supplied with power. If the phase synchronization signal is lost or becomes abnormal in the inverter device to which the respective instrument transformers are connected, An inverter device configured to obtain a phase synchronization signal for an inverter.