JPS6323597A - Power system stabilizing apparatus - Google Patents

Abstract

PURPOSE:To enable sufficient demonstration the effect of a power system stabilizing apparatus, by providing the power system stabilizing apparatus with a discrete and non-cyclic type filter. CONSTITUTION:From a power system stabilizing apparatus 2, the output of generator rotational-frequency signal for input from an input terminal 3 is generated as stabilizing signal, via a high frequency filter 2a, a low frequency filter 2b, a regulator 6, a leading or lagging circuit 2c for correcting the time lag of an exciter 7, a generator, and the like, and a limiter 2d. By an adder circuit 5, a deviation from the reference value of generator terminal voltage for input to an input terminal 1, the output of the power system stabilizing apparatus 2, and the output of a damping circuit 4 are added to one another, and the output is directed to the regulator 6 for controlling the exciter 7. A discrete and non-cyclic type filter for removing axis-torsional component in the generator rotational-frequency signal is used. For the filter 2a.

Description

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

[Conventional technology]

FIG. λ is a block diagram of a general excitation system incorporating a PSS disclosed in, for example, Japanese Patent Publication No. 58-44204.

In the figure, (1) is the input terminal for the deviation of the generator terminal voltage from the reference value, (2) is PSS, and (3) is PSS.
(2) is an input terminal, (4) is a damping circuit, and (5) is an addition circuit that subtracts the output of the damping circuit (4) from the sum of the deviation from the input terminal (1) and the PSS (2) q) output. , (6) is the output of this adder circuit (5) to the excitation device (7).
The regulator that controls (7) is this regulator (
6), which is an excitation device that supplies the field voltage of a generator (not shown). (2a) is a filter circuit for removing high frequency components from the input signal (3) of PSS (2), and has a transfer function characteristic of a normal type.

(2b) is an R-8 filter circuit for excluding low frequency components from the input signal of the same PSS (2), and usually has transfer function characteristics in the form of ++Ta,s. (2c) is a part that corrects the time delay of the regulator (6), exciter (7), generator, etc.
Usually, there is a lead/lag circuit expressed in the form 1+T,X8-, and 1+T, ,8. (2d) is a limiter that controls the output signal of PSS (2) to be an appropriate signal considering the entire excitation system shown in FIG. 1, and to be a bell.

Next, the operation will be explained. When the generator terminal voltage deviates from the reference value, a deviation signal is applied to the input terminal (1), and this deviation signal is amplified by the regulator (6) and sent to the exciter (
7). The excitation device (7) further amplifies it, supplies it to the field of the generator, and controls it to return the deviation of the generator terminal voltage from the reference value to zero. The damping circuit (7) is for stabilizing the voltage control described above.

The above is a general automatic voltage regulator (hereinafter referred to as A).
This function stabilizes the power system by appropriately amplifying and correcting the rotation speed deviation of the generator rotor as a power fluctuation signal and adding it to the adder circuit (5) of the excitation system (referred to as VR). PSS is a control device to improve performance (2)
It is.

The detected rotational speed deviation is applied to the input terminal (3) of the PSS. The high frequency and low frequency components of this signal are cut by a filter (2a) and a filter (2C), respectively, and added to a correction circuit (2C), where appropriate amplification and phase correction are performed. This signal is limited by a limiter (2d) to a signal level below that appropriate for the excitation system, and is added to an adder circuit (5), which controls the output voltage of the excitation device (7) to suppress the fluctuation of the generator rotor. be done.

Next, the characteristics of the PSS filter (2a) will be explained. FIG. 4 shows the frequency characteristics of the π1-type transfer function of this filter (2a). As can be seen from FIG. 4, the gain characteristic is such that the frequency f is approximately 0.7 times as high as f-iπTH, and the gain gradually decreases as the frequency f increases. Similarly, the phase characteristics are delayed by 45° at the point '-'7rTl□, and the larger the frequency f, the closer to -90°.The characteristics of this filter (2a) are determined by determining the filter time constant Tn. High frequency components can be removed.

[Problem that the invention seeks to solve]

Since the conventional PSS is configured as above, it is not possible to completely remove the shaft torsion component whose frequency component is relatively close to the power oscillation signal present at the generator rotation speed, and due to this shaft torsion component, the PSS If the gain of PSS is increased to make the effect more effective, the PSS operation and shaft torsional vibration will cause resonance, so it is necessary to lower the gain of PSS.
There was a problem in that the effect of S was difficult to demonstrate.

These issues are covered in the IEEE report PAS-92JAN.
/FEB1978 P2O4~2] It is known as a whistle.

This invention was made in order to solve the above-mentioned problems, and it is possible to remove the shaft torsion component from the generator rotation speed signal, increase the gain, and create a PSS that can more effectively utilize the PSS effect. The purpose is to obtain.

[Means for solving problems]

The power system stabilizing device according to the present invention is equipped with a discrete acyclic filter at the input of the PSS.

[Effect]

In the PSS of this invention, the axial torsion component is removed by a discrete acyclic filter from the input signal of t'IPSS.
The effect is fully demonstrated.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (2a) is a discrete acyclic filter (hereinafter referred to as a filter) for removing the shaft torsion component present in the generator rotational speed signal. This filter (2a) can be expressed by a block diagram as shown in FIG. In Figure 2, (10-1) to (10-j)
is a function z−Kl expressed by Z transformation, (11-1)
indicates an addition point that adds the input signal and the output signal of function (10-1), and (11-2) to (1t-j) indicate addition points that similarly add signals. The block diagram shown in Figure 2 is represented by a pulse distribution function: H(z)-C1+Z-
can be expressed as 2)...(1+Z-"j).

Figure 8 shows the frequency response characteristic of the pulse transfer function H(z) - (1+z-'').As can be seen in Figure 8, by appropriately selecting the filter constant K and sampling time T, the fundamental wave frequency fO can be adjusted. On the other hand, it becomes possible to remove the fa component.

Next, the operation will be explained. Now PSS input terminal (3)
The generator rotation speed signal input to Co51n2πfoH
-C,5in2πflt+-...+Cjsin2yrf
Suppose that it is given by the expression jt. In this formula, fO is the power system fluctuation frequency, Co is the coefficient applied to it, and f1~
j represents the frequency of the shaft torsion component present in the generator rotational speed signal, and C1 to j represent the coefficients thereof. In the constant of the function (10-1) in Fig. 2, 1 is the axial torsion component C, 5i
A constant for eliminating n2πf,t can be selected based on the characteristics shown in FIG. Similarly, the function (
The constant Kj of 10-D is the axial torsion component Cjsin2πfj
It can be chosen to be a constant for eliminating t. As a result, the output of the filter (2a) is the input signal Co51n2πfot1t of the input terminal (3) of pss, 5in2πf1t
4-・-1-Cjsin2yrf jt Co51n2π of only the power system perturbation component by removing the shaft torsion component
It becomes fot.

In addition, in the second embodiment, only the filter (2a) is shown as a discrete type, but the PSS (2), the damping circuit (4),
The adder circuit (5) and the regulator (6) may be of a discrete type.

Further, in the above embodiment, explanation has been given regarding the removal of the shaft torsion component, but a rotation speed component may be included in addition to the shaft torsion component. Also in the above example! PSS the filter (2a)
Although it is located on the input side of the block in (2), it may be placed at an intermediate position or on the output side, and the same effect as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, since the power system stabilizing device is equipped with a discrete acyclic filter, it is possible to remove the shaft torsion component present in the generator rotation speed, and it is possible to obtain a device that can more effectively exhibit the effect of PSS. It has the effect of

[Brief explanation of drawings]

Fig. 1 is a block diagram of a general excitation system including an embodiment of the present invention and a conventional PSS, Fig. 2 is a block diagram of a discrete acyclic filter, and Fig. 8 is a block diagram of a discrete acyclic filter. -k
) is a frequency response characteristic diagram of a pulse transfer function, and FIG. 4 shows a frequency response characteristic of a conventional PSS filter. (1) is the input terminal for the deviation signal between the generator terminal voltage and the reference value, (2) is the PSS input terminal, (3) is the PSS input terminal,
(4) is a damping circuit, (5) is an excitation system addition circuit,
(6) is a regulator, (7) is an excitation device, (2a) is a discrete acyclic filter, 00 is a function expressed by Z transformation, and OD is an addition point. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Power System Stabilize stabilizes the power system by detecting the generator rotation speed, passing through a gain and phase correction circuit, and then adjusting the amount of excitation of the synchronous generator via an automatic voltage regulator.
1. A power system stabilizing device comprising a discrete acyclic filter for removing shaft torsion components present in a generator rotational speed signal.