JPS61280799A - Power system stabilizer - Google Patents

Abstract

PURPOSE:To improve the transient stability and constant state stability by providing the first system stabilizer set to improve synchronizing power and the second system stabilizer set to improve a brake force. CONSTITUTION:The first PSS (system stabilizer) 8 set to improve synchronizing power and the second PSS (system stabilizer) 2 set to improve a brake force are provided. When a system defect occurs, a rotating speed deviation omega varies. This is collected by a system fluctuation discriminator 9, the gain factor of the second PSS 2 is reduced and the gain factor of the first PSS 8 is increased simultaneously when a defect occurs. When the peak value of the deviation DELTAw becomes a certain value, the gain factors are returned to the original values. The outputs of the first and second PSS 2, 8 are applied to an adder 5 as auxiliary signals of an exciter system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power system stabilization device (PSEI) used in an excitation device for a synchronous generator.

[Conventional technology]

FIG. 4 is a block diagram of a general excitation system incorporating a conventional PEL5 disclosed in, for example, Japanese Patent Publication No. 58-441104.

In the figure (11 is the input terminal for the deviation of the generator terminal voltage from the reference value, +210-iP S S , +31 is the input terminal for 21, +41 fl damping circuit, (5) is from the input terminal Il+ deviation and P S S +
An adder circuit that subtracts the output of the damping circuit (4) from the sum of the output of the adder circuit (5), and a regulator (t?) that controls the excitation device by the output of the adder circuit (5). It is an excitation device that is controlled by this regulator (6) and supplies field voltage for one generator (not shown). (2a) is P S
It has a B12+ input signal function characteristic. (2b)
It is a delay circuit that corrects the time delay of the regulator (6), excitation device (7), generator, etc. (2C) is a limiter that limits the output signal of P S S +21 to an appropriate signal level considering the entire excitation system shown in FIG.

As the input signals for P S S +21, 9 normally 1 rotational speed deviation of the generator rotor, 9 the same wave number deviation of the generator terminal voltage, 1 the output deviation of the generator, etc. are used.

Next, the operation will be explained. When the generator terminal voltage deviates from the reference value, an input terminal +111c deviation signal is added, and this deviation signal is amplified by the regulator (6) and input to the exciter (7) - the exciter (7) further amplifies it. 9 supplied to the field of the generator.

Control is performed to return the deviation of the generator terminal voltage from the reference value to zero. The damping circuit (7) is for completely stabilizing voltage control of 9 or more.

The above is a so-called general self-help voltage regulator (hereinafter referred to as AV
This is the function of the adder circuit (referred to as R) in this excitation system (referred to as R).
P B S +2 is a control device that improves the stability of the power system by appropriately amplifying and correcting an auxiliary signal [for example, rotation speed deviation of a generator rotor, etc.] to 5).
It is 1.

Now consider PI35 which inputs the rotation speed of the generator rotor. The detected rotational speed deviation is applied to the input terminal (3) of the PSB. The DC component and high frequency of this signal are cut by a filter (2a), and the signal is applied to a correction circuit (2b) where it is appropriately amplified and phase corrected. This signal 8+ is limited by the limiter (2C) to a signal level below the appropriate signal level for the excitation system, and the output voltage of the excitation device (7) is added to the adder circuit (6) (1) to suppress the fluctuation of the generator rotor. controlled.

Next, the principle of pss will be explained. FIG. 5 is a block diagram linearly approximating the oscillation of a single-machine infinite system generator as shown in, for example, Electric Kyodo Research Vol. 84, No. 5. In the figure, 1 is the synchronized torque series generated by a generator with a constant field exchange magnetic flux * 'Kl' is the synchronized torque series generated by R, The synchronization torque series, D is the braking torque series generated by the generator with constant magnetic flux, D' is the braking torque series generated by the AVR, and p// is the braking torque series generated by the PI9S. In general, when the power factor is close to 1.0 and the phase angle θ becomes large, D' tends to take a negative value.O Especially in high-speed response and high-gain AVRs, D+D'' may become negative in some cases. , Steady-state stability may not be maintained due to insufficient braking force. In this case, by adding PBBf, braking force D# is generated and stabilization is attempted.

FIG. 6 is an explanatory diagram showing these aspects.

PSS improves braking force by generating an opposite braking force D″ to counteract the negative braking force D′2 generated by high-speed response/high gain AVH. However, PSB is designed to improve the synchronization force. It is not assumed that 1 is very small, or in some cases it may even produce a slightly negative value.

[Problem that the invention seeks to solve]

Since the conventional PSS is configured as described above, it is not possible to improve the synchronization power necessary in the transient region where the generator is greatly shaken immediately after an accident occurs in the power system, and therefore the transient stability is There were drawbacks such as the inability to improve

This invention was made to solve all of the above-mentioned problems, and in the transient region where the generator oscillates greatly, the synchronizing force can be sufficiently increased to improve transient stability.
The purpose of the present invention is to obtain a power system stabilizing device that can fully improve the steady state stability by sufficiently increasing the braking force in the steady state region where the oscillation of the generator is slightly reduced.

[Means for solving problems]

The power system stabilizing device according to the present invention improves the synchronization force using the generator rotation speed or the system frequency as input, and the braking force using the first pss set to improve and the generator output as input signals. The first PSS is provided with a second PSB which is set to the desired value, and the sharpness of the oscillation of the first generator is determined, and the gain elements of the first PSS and the second PSS are changed.

[Effect]

The magnitude of the oscillation of the generator is determined by the PSS oscillation and system oscillation determination circuit in the present invention, and in a region where the oscillation is large, the gain element of the first PSS that has been set is increased to improve the synchronization power.

The gain element of the second PSS is made smaller, and the gain element of the second PSS, which is set to increase the braking force in the area of small vibration, is made thicker, and the gain element of the it PSS is made smaller, and the output of this PEL8 is increased. As an auxiliary signal for the excitation system, the output voltage of the excitation device is controlled to improve the transient stability of the first generator and to improve the damping of #swings.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, [21r1 is the second PSS set to improve the braking force, +81 is the first pss set to improve the synchronization force, and the system for determining the magnitude of the fluctuation of the f9Hj generator. Shake judgment circuit.

(lO) is the input terminal of the system fluctuation determination circuit (9), t:1
ll-j first P S B [21 input signals 1
Generator output signal.

(1υ is the input signal of the second PSel f8), which is a generator rotational speed signal or a system same wave signal.

(8a) A filter circuit for determining the response range for the input signal (3) of iP B S i8).
Normally (8b) is a lead/lag circuit expressed in the form of a regulator (6), an excitation device, and a generator.

(8C) is a limiter that limits the output signal of P El 8 +81 to an appropriate signal level considering the entire excitation system shown in FIG.

As input signals to the system fluctuation determination circuit (9), 1 generator rotor rotation speed deviation 1 generator output deviation 9 generator terminal voltage deviation, etc. are used.

Note that PBB (2), which is set to improve the braking force, has a torque characteristic as shown in Fig. 6, and PBB (2), which has been set to a minimum, has a torque characteristic as shown in Fig. 2. , a relatively large positive Kit occurs.

Next, the operation will be explained. Current system oscillation judgment circuit (9)
Consider the case where the rotation speed deviation of the generator is input to the input terminal (lO) of It changes as shown in Figure 3.During normal operation, the generator rotational speed deviation Δω becomes almost zero, and in this case, the gain element of the second P S S +21 to improve the braking force is increased, and the synchronization force is increased. The first p to improve
The gain element of s s (s) is kept small.

When a system fault occurs, Δω changes as shown in Fig. 8. This is captured by the system fluctuation determination circuit (9), and at the same time as the fault occurs, the second P SS (the gain element of 21 is made smaller and the first P 8 S (Change the gain element of 81 to become larger. This state is continued until the peak value of Δω exceeds a certain value, and when it reaches a certain value, each gain element is returned to its original value.

These first OP S S +21 and second PB
The output of El [8] is added to the adder circuit (6) as an auxiliary signal for the excitation system. This addition is called vector synthesis, and immediately after the occurrence of a system accident, synchronization power is lost. The first thing to improve
P 88 (81 vector components are large and fxb.

Second PSS (2) that improves braking force during steady operation
The vector component of will become large.

Note that in the above embodiment, the transient region and steady state region of the generator's oscillation were determined based on the magnitude of the rotational speed deviation, but even if determined based on the magnitude of the generator output deviation, one generator terminal voltage deviation In the above embodiment, each gain element was switched in 2 stages based on the 9 rotational speed deviations, but it may be switched more finely in n stages, and the same as in the above embodiment may be used. be effective.

〔Effect of the invention〕

As described above, according to the present invention, pss'l is the first pss for improving the synchronizing force, and b is the second pss for improving the braking.
Since each gain element is changed according to the amount of oscillation of the generator, the steady-state stability can be sufficiently improved, and the transient stability can also be sufficiently improved.

[Brief explanation of drawings]

Fig. 1 is a composition diagram of a general excitation system including a PSS according to an embodiment of the present invention, Fig. 2 is a vector diagram explaining the torque characteristics of the PSS set to improve synchronization power, and Fig. 8
The figure is a waveform diagram showing the oscillation of the generator, Fig. 4 is a configuration diagram of a general excitation system including a conventional PuS, and Fig. 5 is a linear approximation of the oscillation of a single-engine infinite generator. block diagram,
FIG. 6 is a vector diagram illustrating the torque characteristics of a conventional PSS set to improve braking force. il+ is the input terminal for the deviation signal between the generator terminal voltage and the reference value, and (2) is the second PE that is set to fully improve the braking force.
18. +31/fi First PSS input terminal. +41 is a damping circuit, and (6) is an excitation system addition circuit. (6) is a regulator, (7) is an excitation device, (8) is a first P 8 S set to improve synchronization power,
(91 is the system oscillation that determines the magnitude of generator oscillation.
constant circuit, +101 is the input terminal of the system fluctuation determination circuit,
(11) indicates the input terminal of the first pss. In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] The amount of excitation of the synchronous generator is adjusted by detecting either the generator output, the generator rotation speed, or the grid frequency, etc., and adjusting it via the automatic voltage regulator after passing through the gain and phase correction circuit. Power grid stabilization device that stabilizes
r System Stabilizer (hereinafter referred to as PSS) includes a system oscillation determination circuit that determines the magnitude of generator oscillation, and a first stabilizer that uses the generator rotational speed or system frequency as an input signal and is set to improve the synchronization power. PSS of
and a second PSS that uses the generator output as an input signal and is set to improve braking force, and according to the amount of oscillation of the generator,
A power system stabilizing device characterized in that gain elements of a first PSS and a second PSS are changed.