JPS63257493A - Excitation controller for synchronous machine - Google Patents

Abstract

PURPOSE:To suppress the sudden boosting of the voltage of a synchronous machine terminal, by adding the signal of counter polarity in proportion to the output of the voltage of the synchronous machine terminal, to the input of a phase controller, when the voltage is established at the time of starting, and by weakening excitation. CONSTITUTION:By a bias signal generator 12, the terminal voltage value of a synchronous machine is detected, and the output of the bias signal of counter polarity in proportion to said value is directed to a phase controller 9. By the bias signal generator 12, it is detected that the terminal voltage of the synchronous machine comes to the rating value of approx. 95-98 % in the proximity of a rating regulating value, and the output of the bias signal generator 12 is cut, then the only output signal of an automatic voltage regulator 7 exsists. Accordingly, the input of maximum rising signal to the phase controller 9 is provided, but the terminal voltage of the synchronous machine immediately comes to the rating regulating value, and so the output of falling signal from the automatic voltage regulator 7 is generated, and by the terminal voltage of the synchronous machine, slight overshooting only is performed, and the voltage is controlled to a rating value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to excitation control during automatic startup using a thyristor rectifier in an excitation control device that supplies excitation current to a field winding of a synchronous machine.

(Conventional technology) Recently, as an excitation method for synchronous machines, a thyristor excitation method using a thyristor rectifier is used because the response speed is extremely fast due to the development of power electronics and maintenance is easy. has been adopted.

In this thyristor excitation scheme, normal voltage establishment is done with an automatic voltage regulator (AVR).

Regarding the excitation device and automatic voltage start-up of this synchronous machine, the fourth
This will be explained with reference to the drawings and FIG. In automatic startup using the conventional thyristor excitation method, when the synchronous machine 1 driven by a prime mover such as a turbine reaches a synchronous specified rotation speed, the field breaker 3 is turned on, and then the initial excitation device 10 is turned on. The terminal voltage of synchronous machine 1 gradually rises, ? ! ! Phase control device when pressure is established? ! ! Take advantage of 9. The phase of the thyristor rectifier 224 is controlled by the output of the automatic voltage regulator 7 which compares the voltage setter 8 and the terminal voltage of the synchronous machine 1, that is, the secondary voltage of the instrument transformer 6, and controls the amount of excitation based on the deviation. , field winding of synchronous machine 1! The terminal voltage of the synchronous machine 1 is controlled by adjusting the field voltage Vt applied to the synchronous machine 2.

(Problem to be Solved by the Invention) As shown in Fig. 5, when the voltage is raised, the automatic voltage regulator 7 continuously sends an excitation strengthening signal due to its basic operation in response to the setting value of the voltage setting device 8. Because the field winding 2 of the synchronous machine 1 has a very large inductance, the terminal voltage of the synchronous machine 1 overshoots the set value.

Particularly among thyristor excitation systems, when the thyristor rectifier is configured with a mixed bridge system, the excitation lowering ability is lower than that of a pure bridge system, resulting in a large amount of overshoot. For this reason, the overvoltage protection relay may operate, and the V/F of the If &
It was also necessary to consider the influence of alcohol tolerance. In order to avoid this, conventionally, the sensitivity of the automatic voltage regulator 7 is lowered or the set value of the voltage setter is set to the lower limit of the mu range to prevent the above-mentioned problem from occurring even if overshoot occurs.

Therefore, in the present invention, when the voltage is established at startup, the synchronous machine terminal voltage is output to the input of the phase control device; a proportional signal of opposite polarity is added, and the excitation is weakened. The purpose is to suppress

[Structure of the invention]

(Means for Solving the Problems) The excitation control device for a synchronous machine of the present invention includes a thyristor rectifier that controls and rectifies an AC power supply and supplies field current to a field winding, and includes a signal output means and a judgment means. and.

The signal output means detects the terminal voltage value of the synchronous machine.

A zero determination means for outputting a bias signal of opposite polarity proportional to this value to the phase control device detects the terminal voltage value and stops outputting the bias signal when this value exceeds a specified value.

(Function) When starting a synchronous machine, if the voltage is below the specified value of the first judgment means, the bias signal of the signal output means is added to the output signal from the automatic voltage regulator to raise the set voltage, and the bias signal of the signal output means is added to the output signal of the signal output means to raise the set voltage. It becomes input. This results in a smooth voltage rise near the specified terminal voltage value. When the specified value is reached, the output of the bias signal is stopped, and the output signal of the automatic voltage mater becomes a phase control device.

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

In FIG. 1, devices, signals, etc. that are similar to those in FIG. 4 are given the same symbols.

FIG. 1 is a block diagram of an excitation device of the present invention, and FIG. 2 is a block diagram of a bias signal generator of the present invention.

The bias signal generator of this embodiment is proportional to the terminal voltage of the synchronous machine 1 by a detection circuit 12-a that detects the terminal voltage of the synchronous machine 1', a bias adjustment circuit 12-b, and a variable limiter circuit 12-C. It outputs an output signal of opposite polarity to the output signal of the automatic voltage glIll device 7, and has means for cutting off this output signal of opposite polarity when the terminal voltage of the synchronous machine 1 reaches a certain specified value.

In the above configuration, the automatic voltage regulator 7 of the synchronous machine 1
The case of automatic startup will be explained using the output characteristic diagram shown in FIG.

When the synchronous machine 1, which is driven by a prime mover such as a turbine, reaches a specified synchronous rotation speed according to the main engine start command, the field breaker 3 and the initial excitation device i10 are turned on, and the field winding 2 of the synchronous machine 1 is initially excited. , and the terminal voltage of synchronous machine 1 gradually rises as shown by curve a. At this time, the rising state is determined by the initial excitation amount, and the phase control bag! ! ! 9 is gate blocked, so the automatic voltage W! is applied as shown in FIG. The sum of the outputs of the III unit 7 and the bias signal generator 12 is the phase control device! 9, but is not involved in voltage control.

When the terminal voltage of the synchronous machine 1 reaches a voltage value sufficient for the phase control device 9 to function, the gate-off state of the phase control device 9 is removed, and the field voltage of the synchronous machine 1 is changed to the terminal voltage of the synchronous machine 1 to a power transformer for excitation. 5 and is controlled by a thyristor rectifier 4.

The thyristor rectifier 4 is controlled by a phase controller 9.
Initially, when the phase control device 9 was turned on, the synchronous machine 1
Since the terminal voltage of the automatic voltage regulator 7 is low, the output of the automatic voltage regulator 7 is outputting an almost maximum increase signal. In addition, since the output of the bias signal generator 12 is also in a low state, the field voltage θ rises almost to the top voltage, and the excitation is strengthened.
As the terminal voltage of the synchronous machine 1 increases, the output of the bias signal generator 12 also increases, and therefore the input voltage of the phase control bag 2!9 decreases.At this time, the automatic voltage regulator 7 The output of is still the maximum raised signal,
If the limit value of the output signal 12-C of the bias signal generator 12 is changed so that the field voltage 8 becomes the no-load field voltage, the terminal voltage of the synchronous machine gradually increases. At that time, the bias signal generator 12 detects that the terminal voltage of the synchronous machine 1 is close to the rated specified value, approximately 95 to 98% of the rated value, and when the output of the bias signal generator 12 is cut off, the automatic voltage regulator 7 is the only output signal, and the maximum increase signal is input to the phase control device 9, but since the synchronous machine terminal voltage quickly reaches the rated specified value, a decrease signal is output from the automatic voltage regulator 7, and the synchronous machine terminal The voltage is controlled to the rated value with only a slight overshoot.

Therefore, it is more likely that the terminal voltage will greatly overshoot when the starting voltage is established.

Furthermore, it goes without saying that a similar effect can be obtained by adding a similar bias signal generator to a field current controlled manual voltage regulator which exhibits the same controllability as an automatic voltage regulator.

〔Effect of the invention〕

As described above, according to the present invention, even when the automatic starting voltage is established by a normal automatic voltage regulator, the terminal voltage of the synchronous machine does not overshoot from the rated specified value, and the voltage is established, so that it dissolves quickly during normal operation. It is possible to provide an excitation control device for a synchronous machine that does not sacrifice the

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an excitation device for a synchronous machine according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a bias signal generator of the present invention.
Fig. 3 is an output characteristic diagram during automatic startup by the excitation device of the synchronous machine of the present invention, Fig. 4 is a block diagram showing the excitation device of a conventional synchronous machine, and Fig. 5 is an automatic start-up diagram of the excitation device of a conventional synchronous machine. It is an output characteristic diagram at the time of starting. 1...Synchronous machine 2...Field winding 4.
...Thyristor rectifier 7...Automatic voltage regulator 8
... Voltage setting device 9 ... Phase control device 1
2... Bias signal generator 12-8... Detection circuit 12-b... Bias amount adjustment circuit 12-C...
Variable limiter circuit 12-d... Voltage comparator circuit representative Patent attorney Nori Chika Ken Yudo Daikomaru Ken Figure 1 Figure 4 Figure 5

Claims (1)

[Scope of Claims] An excitation control device for a synchronous machine including a thyristor rectifier that controls and rectifies an alternating current power supply and supplies a field current to a field winding of the synchronous machine, comprising: detecting a terminal voltage value of the synchronous machine; signal output means for outputting a bias signal of opposite polarity corresponding to the magnitude of this value to a phase control device in which the phase of the thyristor rectifier is controlled; 1. An excitation control device for a synchronous machine, characterized in that the excitation control device for a synchronous machine is provided with a determining means for stopping the output of the bias signal from the signal output means when the bias signal exceeds the limit.