JPH01291640A - In-yard power source switching system for power plant - Google Patents

Abstract

PURPOSE:To prevent erroneous operation sequence by incorporating a main transformer circuitbreaker into an in-yard power source switching interlock. CONSTITUTION:When switching is made such that power is received through a main transformer when an in-yard high voltage bus is receiving power through a starting transformer, an in-yard master switching push button 16a for switching from starting transformer to in-yard transformer is depressed at first to provide a close command to an in-yard transformer circuitbreaker 6 so as to close the circuitbreaker 6. When the close signal is fed to an AND gate 17a, a timer 18a starts operation and a close signal is fed to an in-yard transformer secondary circuitbreaker 8 upon elapse of predetermined time so as to close the secondary circuitbreaker 8. When the close signal for the secondary circuitbreaker 8 is fed to an AND gate 17b, a timer 18b starts operation and an open command is fed to an in-yard high voltage bus link circuitbreaker 10 upon elapse of predetermined time so as to open the bus link circuitbreaker 10. In such a manner, sequential operation is carried out including the main transformer circuitbreaker 6.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is applicable to an in-house power supply of a power plant where the on-site power supply of a power plant is switched from a normal operation system to a backup system, or from a backup system to a normal operation system. This relates to a power supply switching method.

[Conventional technology]

Many thermal power plants and nuclear power plants have unit systems in which a main transformer and an in-station transformer are directly connected to a generator via a phase-separated bus bar. In such unit systems, in recent years, circuits in which a generator breaker (or load switch) is installed between the generator and the main transformer have been considered with the intention of reducing the starting transformer capacity.

Figure 2 is a diagram of this type of on-site power generation system. In the figure, the generator (1) is connected to the negative side of the main transformer (4) via the generator breaker (2), and the secondary side is connected to the main transformer breaker (6) for normal operation. It is connected to the main transformer system bus (7) as a system.

In this case, the generator (1) and generator breaker (2)
between the generator breaker (2) and the main transformer (4),
A phase-separated bus (3) is provided between the main transformer (4) and the station transformer (5). In addition, the main transformer (4
) is connected to the station high voltage bus (9) via a series connection circuit of the station 1 transformer (5) and the station transformer secondary breaker (8). On the other hand, this in-house high-voltage bus (9) is further connected to an in-house high-voltage bus (11) via an in-house high-voltage bus connection breaker (10). This in-house high voltage bus (11) is connected to the starting system bus (15) as a backup system via a starting transformer, a voltage transformer secondary breaker (12), a starting transformer (13), and a starting transformer-secondary breaker (14). It is connected.

Next, the operation will be explained. During normal operation, the main transformer breaker (6) is closed, and the generator (1) and the main transformer system (7) are connected in parallel by the generator breaker (2). In addition, power is supplied to the station high voltage bus (9) from the main transformer system (7) through the main transformer breaker (
6), the main transformer (4), the station transformer (5), and the station transformer secondary breaker (8), and the station high voltage busbar connection breaker (10) is in the open state. It's full. Here, when the generator (1) is stopped in response to surplus electricity on the weekend, so-called weekend shutdown is performed, the main transformer (4) is transferred from the station high voltage bus (9).
), the excitation loss of the main transformer (4) cannot be ignored economically, so the station high-voltage bus connection breaker (10) is closed and the station transformer secondary breaker (
8) is opened, and power is supplied from the starting transformer (13) to the station high-voltage bus (9). On the other hand, when canceling the weekend outage, the state is switched to the state where power is supplied from the starting transformer (13) and the state where power is supplied from the main transformer (4). An interrotter circuit is used. That is, when the on-site switching mask push button (16) is turned on in order to switch from the starting transformer (13) to the on-site transformer (5), a closing command is issued to the on-site transformer secondary breaker (8). Then, a signal indicating that the station switching button (16) is in the on state and a signal indicating that the station transformer secondary breaker (8) is closed are added to the AND gate (17), and further, The output was added to a timer (18), and the output signal of this timer (18) was used as a command to close the in-house high voltage bus line communication breaker (10).

On the other hand, when switching from the on-site transformer (5) to the starting transformer (13) in order to implement a weekend shutdown, although not shown, when the on-site switching mask pushbutton is turned on, the on-site high-voltage bus connection is cut off. An open command is output to the device (10), and then a signal indicating that the station switching button is in the on state and a signal indicating that the station high voltage bus connection breaker (lO) is open are added to the AND gate. Furthermore, the output is added to the timer, and the time-up signal is used as a command to open the secondary circuit breaker (8) of the station transformer.

(Problems to be Solved by the Invention) In the conventional station power supply switching system described above, when the weekend shutdown of the generator (1) is implemented and canceled, the station transformer secondary breaker (8) and the station high voltage bus line communication breaker (lO), but the main transformer breaker (4) was operated individually. As a result, the burden on the operator increases and there is a risk that errors in operating procedures may occur.

This invention was made in order to solve the above problems, and its purpose is to provide an in-station power supply switching system for a power plant that can reduce the burden on operators and prevent operational procedure errors. shall be.

[Means to solve the problem]

The in-station power supply switching system of a power plant according to the present invention switches the power receiving circuit of the in-station power supply bus from the starting transformer to the in-station transformer, and then switches the in-station transformer secondary switch on the condition that the main transformer breaker is closed. When outputting a breaker closing command and switching the power receiving circuit of the station power supply bus from the station transformer to the starting transformer, the main transformer breaker is opened on the condition that the station transformer secondary breaker has opened. Output the command,
The main transformer breaker is also incorporated into the station power supply switching interrouter.

[Effect]

In this invention, the main transformer breaker is also incorporated into the station power supply switching interrotter to perform a series of sequential operations, which reduces the burden on the operator and prevents mistakes in operating procedures.

〔Example〕

Fig. 1 is a control circuit diagram showing the configuration of an embodiment of the present invention. Fig. 1 (a) shows the control circuit diagram when switching from the starting transformer to the main transformer; Each case of switching is shown.

Among these, in Fig. 1(a), the station switching master push button (
The ON operation signal of 16a) is added as a closing command to the main converter breaker (6), and the AND game) (17
It is added as one input to each of a) and (17b). Also, the open signal of the main transformer breaker (6) is applied as the other input of the AND gate (17a), and the output of this AND gate (17a) is applied to the timer (18a).
I can't wait to see it. In addition, Time Araby No. 8 is used as a command to close the station transformer secondary breaker (8). Furthermore, the closing signal of the station transformer secondary breaker (8) is AND
It is added as the other input of the gate (17b). This A
The output of the ND gate (17b) is applied to a timer (18b), and the time-up signal is then used as an opening command for the high voltage bus line breaker (10).

On the other hand, the ON operation signal of the in-house switching mask push button (16a) is sent to the AND gate (17c) via the timer (18c).
The closing signal of the main transformer breaker (6) is inverted by the NOT gate (19a) and becomes the other input. In addition, the output signal of the timer (18a) is passed through the timer (18d) as one input to the AND gate (17d), and the closing signal of the station transformer secondary breaker (8) is inverted by the NOT gate (19b). and are respectively added as the other input of the AND gate (17d). Furthermore, the output signal of the timer (18b) is passed through the timer (18e) to the AND gate (17e), and the open signal of the high voltage bus line breaker (10) is inverted by the NOT gate (19c). The other hand power of the AND gate (17e) is added respectively. And AND gate (17c), (17dl.

The outputs of (17e) are respectively applied to the OR gate (20).

Next, in FIG. 1(b), the station switching mask push button (16b) is used to switch from the station transformer to the starting transformer.
)'s on operation signal is the in-house high-voltage bus line breaker (lO).
is added as a close command for the AND gate (17
f) and (17g) are respectively added as one input. In addition, the closing signal of the in-house high voltage bus line breaker (10) is applied as the other manual power to the AND gate (17f), and the output of this AND gate (17f) is applied to the timer (18).
f), and then the time-up signal is used as a command to open the station transformer secondary breaker (8). moreover,
The open signal of the station transformer secondary breaker (8) is applied to the other hand of the AND gate (17g), and the output of this AND gate (17g) is sent to the main transformer breaker (6) via the timer (18g). Added as an open command.

The operation of this embodiment configured as described above will be explained below.

First, when the station high-voltage bus (9) is receiving power from the starting transformer (13) and is switched to receiving power from the main transformer (4), as shown in Figure 1(a), the "starting" Weird
By turning on the station switching master push button (16a) for the station transformer, a closing command is given to the station transformer breaker (6) to close it. When the closing signal of this main transformer breaker (6) is applied to the AND gate (17a), the timer (18a) starts operating and after a certain period of time has elapsed, the in-station transformer secondary breaker (8) Give an open command to close it. Then, the closing signal of this in-station transformer secondary breaker (8) is connected to the AND gate (17b
), the timer (18b) starts operating and after a certain period of time, the in-house high voltage bus line communication breaker (10)
Give an open command to make it open.

Thus, sequential operation including the main transformer breaker (6) is performed.

On the other hand, when the main transformer breaker (6) close command is output and the main transformer breaker (6) does not close even after the set time of the timer (18c) has elapsed, or when the timer (18c)
When a command to close the station transformer secondary breaker (8) is output from 8a) and the station transformer secondary breaker (8) does not close even after the time set in the timer (18d) has elapsed,
Alternatively, the timer (18b) outputs a command to open the in-house high-voltage bus line breaker (10), and even if the set time of the timer (18e) has elapsed, this in-house high-voltage bus line breaker (10)
) does not open, the AND gate (17a),
The output of (17b) or (17c) becomes significant,
An alarm is output from the OR gate (20).

Thus, the sequential operation described above can be monitored.

Next, when the station high voltage bus (9) is receiving power from the main transformer (4) and is switched to receive power from the starting transformer (13), as shown in Fig. 1(b), Predetermined -
By turning on the on-site switching mask push button (+6b) for “Initiation”, the on-site high voltage bus line communication breaker (lO) is turned on.
Give a close command to close it. The closing signal of this in-station high voltage bus breaker (10) is connected to the AND gate (1
7f), the timer (18f) starts operating and after one hour, the station transformer secondary breaker (8)
Give an open command to make it open. When the open signal of this in-station high voltage bus line breaker (lO) is applied to the AND gate (17g), the timer (18g) starts operating and after a certain period of time, the main transformer breaker (lO) starts operating.
) to open it by giving an open command to it.

Thus, sequential operation including the main transformer breaker (6) is performed.

Although the operation monitoring circuit is omitted in FIG. 1(b), these sequential shutoff operations can be monitored using a configuration similar to that in FIG. 1(a).

Although the above embodiment shows a switching operation interlock using a push button, the same sequential operation and monitoring as described above can be achieved by using a kick signal from a computer that controls the start and stop of units in a power plant instead. It is possible.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the main transformer breaker can also be incorporated into the station power switching interlock, which reduces the burden on the operator and prevents mistakes in operating procedures. It has the effect of being able to prevent this.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are control circuit diagrams of an embodiment of the present invention, Figure 2 is a power generation system diagram to which the present invention is applied, and Figure 3 is a conventional power source switching control circuit diagram in a power plant. . (1): Generator, (2) Two generator breaker,
(4): Main transformer, (5): Station transformer, (6
): Main transformer breaker, (A): Main transformer system, (8)
: Station transformer secondary breaker, (9) Two station high voltage busbars, (10): Station high voltage bus connection breaker, (16a),
(llib): Internal switching master push button, (17a
) ~ (17g): A N D gate, (18a)
~(18g): Timer, (19a) ~(19c): NOT gate, (
20): OR gate. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] The generator is connected to the normal operating system through a series circuit of the first transformer and the first shingle breaker, and the station power supply bus is connected to the series circuit of the second shingle breaker and the second transformer. In a power plant connected to the generator side of the first transformer through a circuit and connected to a backup system through a series circuit of a third breaker and a third transformer, the in-station power supply When switching the power receiving circuit of the bus bar from the third transformer to the second transformer, output a command to open the first shield breaker on the condition that the second shield breaker is opened. An on-site power switching system for power plants that is characterized by: