JPH02273035A - System voltage regulator - Google Patents

Abstract

PURPOSE:To maintain the optimum system voltage at all times by a method wherein a reactive power controller is driven to switch taps by the output signal of a higher value preferential circuit, into which the outputs of potential transformers at the outlet ports of a plurality of neighboring power plants provided with main transformers equipped with tap switchers upon loading are inputted. CONSTITUTION:The secondary side of two main transformers 12a, 12b equipped with tap switchers upon loading for generators 18a, 18b of neighboring power plants connected through a section breaker 11 are in the same potential and are controlled by a central power supplying station. The secondary side voltages of the main transformers 12a, 12b are detected by potential transformers 13a, 13b and are inputted into higher value preferential circuits 15a, 15b through a changeover switch 14 while the outputs of the circuits 15a, 15b are inputted into reactive power controllers 16a, 16b to select either one of the reactive power controllers by a selecting switch 17 and switch the tapes of the main transformers 12a, 12b. The tap can be switched by the output of the higher value preferential circuit even if either one of the potential transformers 13a, 13b is troubled while a selecting switch selects the healthy reactive power controller even when one of the same controllers is troubled. According to this method, the optimum system voltage may be maintained at all times.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) The present invention relates to a voltage regulating device for a power system, and in particular, to a voltage regulating device for a power system, and in particular to a device for regulating voltage of a power system by tap control of main transformers of a plurality of electrically adjacent power plants. The present invention relates to a system voltage regulator.

(Prior Art) In general, system voltage adjustment by a power plant can be roughly divided into two types: one using a single generator and the other using a main transformer. The former adjusts the field current of the generator to supply the reactive power required by the grid at an operating point within the generator's possible output range, and the latter adjusts the field current of the generator to supply the reactive power required by the grid. Electric power is adjusted by switching the taps of the main transformer using a load tap changer.

When using a generator, if the power plant adopts a unit system, it will have a large effect on the station voltage, and if the generator is operated at low excitation, there is a risk of step-out due to sudden changes in the system status. Because of this, there are few power plants that use it.

On the other hand, in the method using the main transformer, as shown in Figure 2, the voltage transformer (PT
) 3 is input to the reactive power control device (AVQR) 4, and the voltage on the grid side is appropriately controlled by switching the taps of the main transformer 2 according to instructions from the central supply. It is widely adopted within the country.

(Problem to be Solved by the Invention) However, even when there are a plurality of electrically adjacent generators, the main transformer 2 each has a reactive power control device 4 to control the taps, or a third As shown in the figure, when the section breaker 5 is open, each reactive power control device 4 switches the taps, and when it is closed, the reactive power control device 4 on the left side of FIG. controls the main transformer taps.

In particular, the latter one reactive power control device 4 controls the taps of the main transformers 2 of both power plants when the power plants are adjacent to each other and the detected voltage of each potential transformer 3 is the same. However, if the potential transformer 3 fails, it will affect the main transformers 2 of all the power plants being controlled, and this will greatly reduce the reliability of the power system. It can be said that it is lacking in some aspects.

The present invention was made in view of the above-mentioned shortcomings of the prior art, and provides a highly reliable grid voltage regulator that does not affect the operation of a power plant even if some of the potential transformers fail. The purpose is to provide.

[Structure of the invention]

(Means for Solving Problem 11) The present invention provides a high level output signal from a potential transformer provided at each outlet of a plurality of electrically adjacent power plants having main transformers with on-load tap changers. The configuration is such that the signal input to the priority circuit and passed through the high value priority circuit drives the reactive power control device, controls the tap of the main transformer, and adjusts the system voltage.

(Function) The present invention is configured as described above, and the output of the potential transformer provided at the outlet of each power plant is input to the high value priority circuit, and the reactive power control device is driven by the maximum voltage signal. Since the load tap changer of the main transformer is operated, for example, even if one of the potential transformers fails and no voltage is output to the secondary side of the potential transformer, the reactive power control device will operate the other normal transformer. Since it receives the signal from the voltage transformer, it functions normally and can maintain the appropriate voltage without disturbing the grid.

(Example) An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a conceptual diagram showing the configuration of a system voltage regulator according to the present invention, and considers a case where two generators 18a and 18b are adjacent to each other.

When two power plants are electrically connected via a section breaker 11, the secondary sides of the two main transformers with on-load tap changers 12a and 12b are at the same potential, and there is no power from the central supply. Consider the case where the voltage at this point is manipulated to adjust the system voltage.

Voltages on the secondary sides of the respective main transformers 12a, 12b are detected by instrument transformers 13a, 13b, and inputted to high value priority circuits 15a, 15b by changeover switches 14, respectively.

This output is transmitted to each reactive power control device [16a, 16
b, and operate the tap changers of the main transformers 12a and 12b using either reactive power control device. A selection switch 17 is used to select a reactive power control device.

In such a configuration, even if either of the potential transformers 13a, 13b fails and a voltage signal cannot be obtained, the high value priority circuit treats the voltage signal of the other potential transformer as positive. Since the signal is sent to the reactive power control device 16a or 16b, the tap of the main transformer can be appropriately switched.

Furthermore, even if either of the reactive power control devices [16a or 16b is out of order, it is possible to switch to the healthy reactive power control device using the selection switch 17, so that highly reliable grid voltage adjustment can be achieved.

In addition, when the section breaker 11 is open and each of the generators 18a and 18b is connected to the grid independently, the changeover switch 14 switches between the voltage transformer and the reactive power control device in the spontaneous type station. Needless to say, the tap switching of the main transformer is controlled by this.

〔Effect of the invention〕

As explained above, according to the present invention, when the main transformer of a power plant is used to adjust the system voltage, the reactive power control device is driven by the maximum output signal of the potential transformer, and the main transformer is adjusted. Since the tap changer is operated, even if voltage does not appear on the secondary side due to a failure in a part of the instrument transformer, the tap changer of the main transformer is reliably controlled and the appropriate voltage is always maintained. It is possible to provide a highly reliable grid voltage regulator that can be used.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing the overall configuration of an embodiment of a system voltage regulator according to the present invention, and FIGS. 2 and 3 are conceptual diagrams showing the configuration of a conventional system voltage regulator. 12a, 12b...Main transformer with on-load tap changer 13a, 13b...Instrument transformer 15a, 15b...High value priority circuit 16a, 16b...Reactive power control device agent Chika Nori, patent attorney Kendai Kendai (U, Rei) Diagram procedure amendment (voluntary) Heisei

Claims (1)

[Claims] The output signals of the voltage transformers installed at the exits of multiple adjacent power plants that have main transformers with on-load tap changers are input to a high value priority circuit, and the signals passed through the high value priority circuit are used to control reactive power. 1. A system voltage regulator, which adjusts a system voltage by driving the device and controlling a tap of the main transformer.