JPH0514504B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a tap control device for a load voltage regulating transformer in a power plant.

Technical background of the invention and its problems Recently, large-capacity power plants have installed load voltage adjustment transformers within the power plants, and the power generated by the generator is boosted to an ultra-high voltage by the load voltage adjustment transformer, and then transmitted at ultra-high voltage. A method of connecting to electric wires is now being adopted.

In pumped storage power plants, the voltage on the generator-motor side must be kept at the rated voltage for system stability. During generator operation, the generator motor voltage is controlled at a constant level by the generator motor automatic voltage regulator, so the automatic voltage regulator of the load voltage adjustment transformer and the voltage setting of the generator motor automatic voltage regulator If there is a difference, the generator-motor terminal voltage will be controlled to the set voltage of the generator-motor's automatic voltage regulator. However, even if the tap is switched, the voltage does not change and the tap is eventually controlled to the limit value. Excludes automatic voltage regulators for regulating transformers.

Recent hydroelectric power plants are being constructed in increasingly remote areas due to locational conditions, and as a result, the distance of power transmission lines to the power demand area becomes longer, causing voltage drops due to the impedance of the power transmission lines. If the grid bus voltage fluctuates during generator-generator operation, the generator-generator motor automatic voltage regulator will control the generator-generator motor voltage at a constant level, but if the grid voltage fluctuation goes outside the control range of the generator-generator automatic voltage regulator. This results in an unstable state, which is not a desirable operating state.

In addition, load voltage adjustment transformers conventionally installed in pumped storage power plants have a wide voltage adjustment range in order to maintain the terminal voltage of the generator-generator and the voltage at the load end at specified values, and as the capacity of the generator-generator increases, parallel A disconnector is installed on the high pressure side. Therefore, when connecting a generator-generator to the grid, taps proportional to the number of taps of the on-load voltage regulating transformer are installed on the secondary side of the instrument transformer for the automatic parallel connection device, and the number of taps of the on-load voltage regulating transformer is A method was used to correct the on-load voltage adjustment transformer by always matching the tap on the secondary side of the voltage transformer for the automatic line-in device. This method requires an auxiliary relay proportional to the number of taps on the on-load voltage adjustment transformer, and also requires taps on the secondary side of the instrument transformer for automatic line-in equipment. The transformer needs to be equipped with a tap, the number of auxiliary relays increases, the wiring time increases, and it becomes expensive.
There were also problems such as maintenance and inspection taking too much time.

Purpose of the Invention The present invention provides a tap control device for the on-load voltage regulating transformer so that the rated voltage ratio of the on-load voltage regulating transformer can be adjusted by the tap controlling device of the on-load voltage regulating transformer prior to the operation of the generator motor. By controlling the taps of the on-load voltage adjustment transformer so that the voltage drop in the power generation and pumping storage operation system is predetermined, the voltage drop in the power generation and pumping storage operation system is determined in advance. It is an object of the present invention to provide a tap control device that can control a generator motor to a tap value that is set to a certain value and stably operate a generator motor within a range that does not exceed the capacity of the generator motor.

SUMMARY OF THE INVENTION That is, the present invention, in a power plant having an on-load voltage regulating transformer, controls the tap of the on-load voltage regulating transformer to a tap value that corresponds to the rated voltage ratio of the on-load voltage regulating transformer prior to power generation or pumping operation. When this condition is satisfied, power generation and pumping operation are started, and the power generation motive is started, and after the speed is equalized, the generator machine is connected to the grid, and the on-load voltage adjustment transformer is adjusted to the preset tap value. This is a tap control device that makes it possible to operate the generator-generator and the system stably by controlling the terminal voltage of the generator-generator to the rated voltage.

Embodiment of the Invention An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows the power generation system at the power station. That is, in FIG. 1, the G/M is a generator-generator 6, and the output terminal of the generator-generator 6 is connected in sequence to an instrument transformer 5, an on-load voltage adjustment transformer 3, and a variable train disconnector 2. Connect to bus 1.

The on-load voltage regulating transformer 3 is connected to a tap control device 4 for the on-load voltage regulating transformer, which controls the tap of the on-load voltage regulating transformer 3 to a preset tap value prior to power generation and pumping operation. It is.

The automatic paralleling device 8 is connected in parallel with the load voltage adjustment transformer 3 and the parallel shield breaker 2 to the automatic paralleling device instrument transformer 7, and is connected to the automatic paralleling device instrument transformer 7. , the other end of the automatic paralleling device instrument transformer 7 is connected to the system bus 1. The other end of the automatic paralleling device 8 is connected to the potential transformer 5.

EX is an excitation device 10 that applies exciting current to the field winding 11 of the generator-motor 6, and an automatic voltage regulator (not shown) for the generator-motor is built therein. A field excitation or disconnection contact 12 is provided between the excitation device 10 and the field winding 11, and is connected in parallel with the field winding 11. A discharge resistor 13 is connected in series with a contact 14 of a field magnet or disconnector that opens when a command to stop the generator motor 6 is issued.

Fig. 2 shows the main circuit of the tap control device of the load voltage adjustment transformer, in which the tap switching drive motor 25 includes an electromagnetic contactor 24 for lifting the tap, an electromagnetic contactor 23 for lowering the tap, and a wire cutter for wiring. 22 are sequentially connected to the power supply bus 21.

FIG. 3 shows a circuit diagram of the tap control device. At one end of the tap lifting electromagnetic contactor coil 34,
Tap control device 43 for voltage regulating transformer on load that closes when the actual tap value becomes less than the rated voltage ratio tap value
-24 output contacts 32 are connected to one control power supply bus 39 by connecting the normally closed contact 31 (contact that closes when the power generator is at rest) of the shingle disconnector 52 for parallel use. The tap control device 4 for the voltage regulating transformer on load is connected in parallel to the series circuit of the normally closed contact 31 and the output contact 32 of the tap control device 43-24 for the voltage regulating transformer on load.
A series circuit 35 is connected between the contact 36 that closes when 3-24 falls below the specified tap value and the normally open contact 52 (contact that closes during generator generator operation) of the parallel disconnector 2 shown in FIG. do. The other end of the tap-up magnetic contactor coil 34 is connected to a control power supply bus 40 .

In addition, a tap control device 4 for a load voltage adjustment transformer that closes when the actual tap value exceeds the rated voltage ratio tap value is placed at one end of the tap lowering electromagnetic contactor coil 38.
It is connected to the normally closed contact 31 to which the output contact 33 of No. 3-42 was connected, and the other end is connected to the control power supply bus 39. A contact in parallel with the series circuit of the normally closed contact 31 and the output contact 33 of the on-load voltage regulating transformer tap control device 43-24 that closes when the on-load voltage regulating transformer tap control device 43-24 reaches a specified tap value or more. 37 and the series circuit of the normally open contact 35 are connected. The other end of the tap-lowering electromagnetic contactor coil 38 is connected to a control power supply bus 40 .

Next, the operation of the tap control device for the on-load voltage regulating transformer of a pumped storage power plant constructed as described above will be explained with reference to the operational block diagram shown in FIG.
First, when the generator generator is inactive, the parallel disconnector 52 in the tap control device of the on-load voltage regulating transformer is in a tripped state, so the normally open contact 52a is open and the normally closed contact 52b is closed. Output contact 24LR-3 of tap control device 43-24 of voltage regulating transformer;
24LR-4 is excluded, and the output contact 24 of the tap control device 43-24 for the load voltage regulating transformer is excluded.
Only the conditions for LR-1 and 24LR-2 apply.

In addition, during the generator generator operation, the tap control device of the load voltage adjustment transformer is used in parallel with the disconnector 52.
is closed, the normally closed contact 52b is open, and the normally open contact 52a is closed, and the output contacts 24LR-1 and 24LR-2 of the automatic voltage regulator for the load voltage adjustment transformer are closed.
The conditions are excluded and the output contacts 24LR-3, 2 of the tap control device 43-24 for the on-load voltage regulating transformer are excluded.
Only 4L-4 conditions apply.

Figure 5 shows a block diagram of the tap control device.The actual tap value of the on-load voltage regulating transformer is input to the BCD converter BCD.CONV in the tap control device, and the tap value signal is converted into a BCD signal. Tap value comparator COMP1 and tap value comparator COMP
Enter 2. Also, the rated voltage ratio tap setting device
Normally closed contact 52b of sheath disconnection 52 for parallel use of SET-1
The pre-tap setter SET-2 is connected in parallel to the tap value comparator COMP-1 through the tap value comparator COMP-1.
Enter 2. First, rated voltage ratio tap control will be explained.

The actual tap value signal of the on-load voltage regulating transformer input to the tap value comparator COMP1 is compared with the tap value signal set by the rated voltage ratio tap setter SET-1, and the result is input to the output device CONT-1. Masu. The output device CONT-1 outputs the compared input to the actual tap value of the load voltage adjustment transformer.
If it is lower than the tap value of SET-1, the output device
Tap price increase command contact 24LR by CONT-1
-3 is output, and if the actual tap value of the on-load voltage adjustment transformer is higher than the tap value of the setting device SET-1, the output device CONT-1 outputs the tap value reduction command contact 24LR-2, and the rated voltage ratio The output device continues until the tap setting value and actual tap value match.
CONT-1 is the tap value increase/decrease command output 24
LR-1 and 24LR-2 are output, and when the rated voltage ratio tap setting value and the actual tap value match, the output device will raise and the lowering command output 24LR-1 and 24LR-2 will be stopped.

Next, advance tap control will be explained. As explained in the rated voltage ratio control, the output device CONT-2 is operated until the pre-tap setting value and the actual tap value match.
As a result, tap price increase command output 24LR-3 and tap price decrease command output 24LR-4 are output.

Effects of the Invention According to the above explanation, before the generator motor is added to the system, the tap value of the load voltage regulating transformer is controlled to the rated voltage ratio, and after the generator motor is added to the system, the tap value is controlled to the rated voltage ratio. By controlling the voltage, it is possible to control the terminal voltage of the generator motor before and after joining the grid to the rated voltage, stabilize the grid, and perform stable operation within the capacity of the generator motor.

[Brief explanation of the drawing]

Fig. 1 is a single line diagram of the present invention, Fig. 2 is a main circuit diagram of a tap control device for a load voltage regulating transformer, and Fig. 3 is a main circuit diagram of a tap control device for a load voltage regulating transformer.
4 is a block diagram of a control circuit for a voltage regulating transformer on load, and FIG. 5 is a block diagram of a tap control device for a voltage regulating transformer on load. 1...System bus bar, 2...Parallel cable disconnector, 3...
...Load voltage regulation transformer, 4...Tap control device, 5...Instrument transformer for automatic voltage regulator, 6...
...Power generator, 7...Instrument transformer for automatic parallel entry device, 8...Automatic parallel entry device, 10...Exciter, 1
1... Field winding, 12... Field winding and disconnection main contact,
13...Discharge resistor, 14...Field liner and disconnector auxiliary contact, 21...Power supply bus, 22...Wiring liner and disconnector, 23...Magnetic contactor for tap lowering, 24...
Electromagnetic contactor for tap lifting, 25... Electric motor for tap switching drive, 31... Normally closed contact for parallel breaker,
32...Tap control device output contact (generator motor rated voltage ratio tap control increase command), 33...Tap control device output contact (generator motor rated voltage ratio tap control decrease command), 34...Tap increase electromagnetic Contactor coil, 35... Parallel breaker normally open contact,
36...Tap control device 43-24 output contact (closed below specified tap), 37...Tap control device 4
3-24 output contact (closed when the specified tap or more is reached), 38
...Magnetic contactor coil for tap lowering, 39...Control power bus P, 40...Control power bus N.

Claims (1)

[Claims] 1. In a power plant having an on-load voltage regulating transformer, before the generator motor is added to the system, the actual tap value of the on-load voltage regulating transformer and the rated voltage ratio tap value are compared, and the actual tap value is determined to be equal to the rated voltage ratio. a first control means that outputs a tap increase signal when the actual tap value is smaller than the rated voltage ratio tap value, and outputs a tap decrease signal when the actual tap value is larger than the rated voltage ratio tap value; After inputting, the actual tap value of the on-load voltage regulating transformer is compared with a preset set tap value, and if the actual tap value is smaller than the set tap value, outputs a tap value increase signal; A tap control device comprising: second control means for outputting a tap price reduction signal when the actual tap value is larger than the set tap value.