JPS59162724A - Power system stabilizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic voltage regulator (hereinafter abbreviated as AVR) for an AC synchronous generator that is connected to a power system and operates, and its AVH.
This relates to a power system stabilizing device added to the system.

2. Description of the Related Art Conventionally, a control method shown in FIG. 1 is known as this type of power system stabilizing device (hereinafter abbreviated as PSS). In the figure, 1 is a PSS control circuit, and an AVR control circuit 2 is connected to the output stage of the PSS control circuit 1. el
is another input signal of the AVR control circuit 2, which is a generator terminal voltage signal, and e2 is an AVR control circuit output signal of the AVR control circuit 2, which acts as an input signal to the exciter of the AC synchronous generator. e5 is an active power signal of the AC synchronous generator.

Next, the operation of the conventional device shown in FIG. 1 will be explained below. Generally, when a generator control signal with a large power level difference or rate of change is input to a power system and a power fluctuation occurs, the active power output of the AC synchronous generator may oscillate and not attenuate easily. Further, when the active power output of the generator exhibits an aspect of oscillation divergence, the generator active power signal e5 is inputted to the PSS control circuit 1, and the output of the PSS control circuit 1 whose phase has been appropriately adjusted is input to the AVR.
When added to the control circuit 2 as shown in the figure, the attenuation of the above-mentioned force oscillations is greatly improved and system oscillations can be stabilized. Because of this principle of power fluctuation stabilization, the PSS control circuit 1 is generally called a power system stabilizing device.

Therefore, in addition to the active power signal e3 of the generator, the rotational angular velocity signal ω of the generator and the power system frequency signal f are sometimes used as input signals to the PSS control circuit 1. A method using the generator's active power signal e5 is often adopted because it is resistant to noise and has a large effect in suppressing power fluctuations. Pss control circuit 1 that uses the active power signal e5 of this generator as an input signal
is called the general kP input PSS.

However, the above-mentioned P input PSS works effectively when the magnitude of the mechanical torque used by the water wheel or steam turbine to drive the generator is constant, that is, when the generator is in steady operation.
When the output of the generator is changed by an external command, such as when the output of the generator is increased or decreased, side effects may be induced and the terminal voltage of the generator may abnormally decrease or increase. This abnormal drop in generator terminal voltage,
Alternatively, the rise depends on the speed at which the output voltage of the generator is changed, and there is an extremely serious drawback that the more rapid the output voltage is changed, the more the generator terminal voltage drops or rises, which will impede the operation of the generator. there were.

The present invention has been made in order to eliminate the drawbacks of the conventional devices as described above. A PSSS clock path that takes the generator control signal as an input signal is installed to temporarily lock the output of Pss when the mechanical torque to the generator suddenly changes, and then return to normal after a certain period of time.
An object of the present invention is to provide a power system stabilizing device that prevents power fluctuations caused by side effects of S.

An embodiment of the present invention will be briefly described below.

In FIG. 2, the same parts as in FIG. 1 are indicated by the same reference numerals. In FIG. 2, numeral 3 operates changeover switches 41 and 42 which are interlocked with a Pss lock circuit.

eII is an input signal to the Pss lock circuit 3, which is a generator output setting device signal of a governor control system, a guide vane opening signal of a water turbine governor, or a first pulp signal of steam power, that is, a generator control signal. . Further, FIG. 3 shows another embodiment of the present invention. In this Figure 3, 2a is a high transient gain AVR control circuit used with Pss, which has high circuit characteristics when the transient gain is around 1H2, and 2b is a low transient gain AVR control circuit used when PSS is locked. It has a circuit characteristic in which the transient gain is lower than 2a.

Next, the operation of the present invention will be explained with reference to FIGS. 2 and 3. Generally speaking, considering the responsiveness of the generator control system, changes in the mechanical torque of the generator usually occur due to the generator control signal eII, the generator output setter signal of the governor control system, or the guide vane opening of the water turbine governor. This is when the signal, or the first pulp signal of steam power, changes. Therefore, when it is necessary to change the generator output voltage, the Pss lock circuit 3 automatically detects that the magnitude of the generator control signal or its rate of change has exceeded a certain value, and As a result, in the state before a change in mechanical torque occurs, switch to the two sets of changeover switches 41 and 42 to give a drive command, and perform interlocking switching to prevent the output signal of the Pss control circuit 1 from being applied to the AVR control circuit 2. PSSSS indicates that the level value or rate of change of the generator control signal e) has become below a certain value at the point when the rotation speed of the generator has stabilized and the change in mechanical torque to the generator has become small. Check the switch 4 again.
1.42, the output signal of PSS control circuit 1 becomes AV
It is added to the R control circuit 2 or the high transient gain AVR control circuit 2a of FIG. 3 to restore the PSS control circuit 1 to its operating state.

However, when the PSS control circuit 1 is locked, the AV
The negative damping effect of R may deteriorate the attenuation of power fluctuations, which may impede operation, so when there is such a possibility, the AVR is switched to the low transient gain AVR control circuit 2b as in the embodiment shown in Figure 3. By this, AVR
The problem of negative damping effect can be alleviated.

As described above, according to the present invention, when a sudden change in the mechanical torque to the generator is predicted by the generator output setting signal or the generator control signal such as the guide vane opening signal or the fast pulp signal, the generator control Detect the level value or rate of change of the signal, switch to cut off the function of the PSS control circuit, pull it off with a switch, and after confirming that the level value or rate of change has exceeded a certain value, switch the PSS control circuit. Since the switch was returned to its original state and the Pss control circuit was activated, the side effect of power fluctuation due to the Pss of the P input,
That is, it is possible to reliably prevent an abnormal drop or rise in the voltage at the generator terminals, and at the same time, it has remarkable practical effects such as being able to supply power with high quality.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional power system stabilization device;
FIG. 3 is a block diagram of a power system stabilizing device according to an embodiment of the present invention, and FIG. 3 is a block diagram of a power system stabilizing device showing another embodiment of the present invention. 1... pss control circuit, 2... AVR control circuit, 3
. . . PSS lock circuit, A1, 42 . . . Changeover switch In addition, the same reference numerals in the drawings indicate the same or equivalent parts. Agent Shin Kuzuno (1 person)

Claims (2)

[Claims] (1) PS that operates by inputting the generator's active power signal
an AVR control circuit that receives the output signal of the Pss control circuit and the generator terminal voltage signal as input, and a power system that transmits the output signal of the AVR control circuit to the exciter of the synchronous generator. The stabilization device includes a PSSS clock circuit that operates by detecting the level value or rate of change of the generator signal, and an output signal of the psS lock circuit that controls the generator control signal when the generator control signal deviates from a predetermined value. Two sets of changeover switches are provided to separate the active power signal and the output signal of the PSS control circuit, and the changeover switch is reset when the level value or rate of change of the generator control signal becomes below a certain value. A power system stabilizing device that is capable of operating a Pss control circuit normally. (2) The input signal of the pss control circuit and the output signal of the AVR control circuit are controlled by the operation of the pss lock circuit and the PSSS clock circuit, which operate when the level value or rate of change of the generator control signal exceeds a predetermined value. 2. The power system stabilizing device according to claim 1, wherein a normally operating high transient gain AVR control circuit provided between the changeover switches is switched to a low transient gain AVR control circuit.