JPS63202299A - Automatic voltage regulator - Google Patents

Abstract

PURPOSE:To suppress a variation in a generator voltage by differentiating a harmonic wave component presented at the voltage and applying it as a control signal to a control system. CONSTITUTION:A harmonic wave detector 20 detects the harmonic wave component of the output voltage waveform of a generator 3 produced by a power transformer 5, such as a third harmonic wave, differentiates the detection signal, and applies it to an amplifier 8. The amplifier 8 calculates a deviation between the set value of a bias setter 9, and the sum result of a voltage deviation input from a comparison calculator 6, a hunting preventive signal input from a hunting preventing circuit, and the detection signal of a harmonic wave detector 20, and outputs it to a gate controller 11. Thus, a control system operates to suppress it at the stage immediately before a generator voltage is abruptly varied, thereby suppressing the variation in the generator voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an automatic voltage regulator that controls the output voltage of a single generator to a predetermined value.

(Prior Art) FIG. 3 shows a conventional example of an automatic voltage regulator that controls a generator output voltage to a predetermined value using an AC exciter.

This automatic voltage regulator consists of an automatic voltage regulator AVR and a manual voltage regulator MVR, one of which is selected during operation according to the switching amount Sw. The AC exciter 1 is driven by the outputs of the automatic voltage regulator AVR and the manual voltage regulator MVR. The output of this AC exciter 1 is rectified by the main rectifier 2 and applied to the field winding of the generator 3,
The output of the generator 3 changes depending on the exciting current. Note that the power system is of course three-phase.

In the automatic voltage regulator AVH, the voltage detector 4 detects the output voltage of the generator 3 taken out by the voltage transformer 5, and its detection signal is applied to the comparator 6. The comparison calculator 6 calculates the deviation between the target voltage set in the voltage setting device 7 and the voltage detected by the voltage detector 4, and the deviation is added to the amplifier 8.

The amplifier 8 calculates the deviation between the set value of the bias setting device 9 and the result of addition of the deviation input from the comparator 6 and the disturbance prevention signal input from the disturbance prevention circuit 10, and outputs it to the gate control section 11. do.

The gate control unit 11 forms a pulse whose phase changes according to the input signal and outputs it as a gate pulse for the thyristor 12 . Note that the bias setting device 9 sets the phase of the gate pulse when the output voltage of the generator 3 reaches the target value. Also.

The disturbance prevention circuit 10 includes the transformer 1 of the manual voltage regulator MVR.
The output voltage of the AC exciter 1 detected by the AC exciter 3 is differentiated to form a disturbance prevention signal.

In the manual voltage regulator MVR, the output voltage of the AC exciter 1 detected by the transformer 13 is output from the AC stabilizing circuit 1.
4 to the inductive voltage regulator 15.

Subject to manual changes. Then, the input of the sub-rectifier 16 that rectifies the drive signal of the AC exciter 1 is adjusted by the output of the induced voltage regulator 16.

When the automatic voltage control unit AVR is selected by the switch SW, the output of the sub-rectifier 16 is connected to the thyristor 12.
is added to the bias value of the output of the thyristor 12. When VR is selected as the manual voltage control section by the switch SV, the output of the sub-rectifier 16 is directly applied to the AC exciter 1.

The thyristor 12 is a permanent motor cinerator 17
The output AC voltage is rectified and superimposed on the signal applied from the sub-rectifier 16, and the output is applied to the AC exciter l via the switch Sv.

Further, the initial exciter 18 is for driving the AC exciter 1 at startup, and the switch 19 is for applying the output of the initial exciter 18 to the AC exciter 1.

With the above configuration, at the time of starting, the switch 19 is switched to the manual (manual voltage regulator MVR) side.
is turned on to start the AC exciter 1, and when starting is completed, the induction voltage regulator 15 is adjusted and the generator 3 is controlled. Thereby, the output voltage of the generator 3 is controlled by the manual voltage regulator MVR.

When the output voltage of the generator 3 reaches a predetermined value, the switch Sv is switched to the automatic (automatic voltage regulator AVR) side. As a result, the manual voltage regulator MV is controlled by the thyristor 12.
The output of R and the output of automatic voltage regulator AVH are applied to AC exciter 1, and the output voltage of generator 3 is controlled to a predetermined value.

(Problems to be Solved by the Invention) However, in such a conventional device, one generator 3 When the output voltage fluctuates, there will be a certain amount of time delay between when the output voltage fluctuates and when it recovers to the set voltage.

Causes of generator voltage fluctuations include external load or output fluctuations, cross currents, short circuits in power transmission systems, ground faults, pulsating currents, and tidal currents. The manner of these fluctuations is sudden, and therefore, the above-mentioned conventional apparatus has the disadvantage of not being able to adequately cope with such fluctuations.

The present invention is intended to solve the problems of the prior art, and aims to provide an automatic voltage regulator that can adequately cope with sudden changes in generator voltage.

[Structure of the Invention] (Means for Solving the Problems) It has been observed that normally, when the generator voltage suddenly changes, harmonics are outputted prior to the sudden change.

Therefore, the present invention detects the harmonic components present in the generator voltage, differentiates the harmonic components, and provides the differentiated harmonic components as a control signal to the control system.

(Function) As a result, the control system acts to suppress a sudden change in the generator voltage immediately before it changes, and it is possible to suppress fluctuations in the generator voltage.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an automatic voltage regulator according to an embodiment of the present invention. In this figure, the same parts and corresponding parts as in FIG. 3 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In the figure, a harmonic detector 20 detects a harmonic component, for example, the third harmonic, of the output voltage waveform of the generator 3 extracted by the electric quadrangle 5, and the detected signal is differentiated and sent to the amplifier 8. added to.

The amplifier 8 calculates the deviation between the setting value of the bias setting device 9, the deviation input from the comparator 6, the disturbance prevention signal input from the disturbance prevention circuit 10, and the detection signal of the harmonic detector 20. , and outputs it to the gate control section 11.

Therefore, when the output voltage of the generator 3 suddenly changes, the harmonic components that occur in advance are detected by the harmonic detector 20, and the thyristor 12 is activated in accordance with the detection signal.
is controlled.

As a result, the output of the AC exciter 1 changes, the generator 3 is controlled to suppress fluctuations in its output voltage, and as a result, the output fluctuations of the generator 3 are suppressed.

An example of the harmonic detector 20 is shown in FIG.

In the figure, the primary side of a Δ-Y connected transformer 21 is connected to the secondary side of a quadrature transformer 5. transformer 21
A resistor circuit 22 for detecting three-phase imbalance when harmonics are generated and a three-phase rectifier circuit 23 are connected to the secondary side.

The output of the three-phase rectifier circuit 23 is applied to the reference signal input terminal of the comparator 24, and the output of the resistance circuit 22 is applied to the comparison signal input terminal of the comparator 24, and the output signal of the comparator 24 is
It is output to the amplifier 8 via the differential capacitor 25.

When no harmonic components occur in the output voltage of the generator 3, the output of the resistor circuit 22 is approximately O volts, and therefore the output of the comparator 24 does not change, so at this time, the output of the differential capacitor 25 does not change.

When a harmonic component occurs in the output voltage of the generator 3, a three-phase unbalance occurs, and a signal having a polarity, level, and waveform according to the unbalanced state is output from the resistance circuit 22.

As a result, the output of the comparator 24 changes, the change is differentiated by the differential capacitor 25, and a harmonic detection signal corresponding to the polarity and level of the harmonic component is output to the amplifier 8.

In this way, harmonic components included in the output voltage of the generator 3 are detected. In this case, in order to prevent the control of the automatic voltage regulator AVH, which is performed in response to voltage fluctuations after harmonic components are generated, from being affected, a differential capacitor is installed so that the control by harmonic components can be completed in a short time. 25
is used.

By the way, in the embodiment described above, the generator is controlled using an AC exciter, but other automatic voltage regulators,
For example, it can also be applied to those using a DC exciter. Further, the present invention can also be applied to alternating current generators that have many load and output fluctuations.

[Effects of the Invention] As explained above, according to the present invention, since the control system acts to suppress the sudden change in the generator voltage immediately before it changes, it is possible to suppress fluctuations in the generator voltage. This effect is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an automatic voltage regulator according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of a harmonic detector, and FIG. 3 is a block diagram illustrating a conventional device. AVR... automatic voltage regulator, MVR... manual voltage regulator, 1... AC exciter, 2... main rectifier, 3...
- Generator, 20... Harmonic detector, 21... 3-phase transformer, 22... Resistance circuit, 23... 3-phase rectifier circuit, 24... Comparator, 25... Differential capacitor .

Claims (1)

[Claims] An automatic voltage regulator for controlling a generator output voltage to a predetermined value, further comprising harmonic detection means for outputting a differential value of a harmonic component of the generator output voltage as a control signal to the automatic voltage regulator. automatic voltage regulator.