JP2573103Y2 - Excitation controller for synchronous machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excitation control device for a synchronous machine.

[0002]

2. Description of the Related Art FIG. 1 is a diagram showing the configuration of a general conventional excitation system disclosed in, for example, Japanese Patent Application Laid-Open No. 58-176000, wherein 1 is a synchronous machine, 2 is its field winding, Reference numeral 3 denotes an exciter that supplies a field current to the field winding 2, 4 denotes an instrument transformer (hereinafter, referred to as PT) for detecting the voltage of the synchronous machine 1, and 5 denotes the synchronous machine 1. An instrument transformer (hereinafter referred to as CT) for detecting current, 6 is an automatic voltage regulator (hereinafter A) for controlling the voltage of the synchronous machine 1 to be constant.
VR) for detecting the output of the above PT4
61. Reference unit 6 for creating a control target value for the voltage of synchronous machine 1
2. Signals of the amplification unit A63, which increases the difference by taking the difference between the reference unit 62 and the voltage detection unit 61, the phase compensation unit 64 for improving the stability of voltage control, and other additional function devices (described later). And an amplification section B66 for further increasing the output of the addition section 65 and outputting a signal to the exciter 3.

[0003] Reference numeral 7 denotes a power system stabilizing device for detecting power based on the output signals of the PT4 and CT5 and providing an auxiliary signal to the AVR 6 to enhance the stability of the system. Reference numeral 8 denotes an output signal of the PT4 and CT5. V / F limiter for detecting a V / F value (a value obtained by dividing a voltage by a frequency) and applying an auxiliary signal to the AVR 6 to perform limit control so that the V / HZ value does not exceed a predetermined value. , 9 are low-excitation limiting devices that detect power and reactive power based on the output signals of the PT4 and CT5, and limit and control the operating state of the synchronous machine 1 by applying an auxiliary signal to the AVR 6 so as not to become lower than a predetermined value. , 10 are shunts for detecting a current flowing through the field winding 2, and 11 are for detecting an overexcitation state based on an output signal of the shunt 10.
By providing an auxiliary signal in R 6, a overexcitation limiting device for limiting control overexcitation.

Next, the operation will be described. The output voltage of the synchronous machine 1 is stepped down by the PT 4, and the signal is input to the AVR 6 . In the AVR6, the signal of the PT4 is first detected by the voltage detection unit 61, and is a signal (usually a DC signal) that can be easily amplified or added
Is converted to The value of the reference unit 62 is a control target value for the AVR 6 that is trying to control the voltage of the synchronous machine 1.
The difference between the reference section 62 and the voltage detection section 61 is calculated, and an amplifier A 63
Is increased to an appropriate value.

If this signal is a positive value, the output voltage of the synchronous machine 1 is lower than the control target voltage value set in the reference section 62, and thus the AVR 6 increases the output of the exciter 3 by a control signal. Means that it is necessary to increase the current flowing through the field winding 2 and increase the output voltage of the synchronous machine 1. The phase compensator 64 compensates for the output of the amplifier A63 in order to enhance the stability of the voltage control, and the adder 65 applies various attached devices (system stabilizing device 7, V / V) to the output signal of the phase compensator 64. The output of the F limiter 8 and the like are added, and the signal is further amplified appropriately in the amplification section B66 and a signal proportional to the field current output from the exciter 3 is output to the exciter 3 (that is, the exciter). 3 also has a single amplification function).
Is controlled so as to become the control target value set by the reference unit 62 in the AVR 6 . To perform excitation control,
A voltage detector 61 for detecting the signal of PT4, an active power converter 71 for detecting the active power, and a V for detecting the signal of the V / F ratio.
Various input converters such as a / F converter 81 and a reactive power converter 91 for detecting a reactive power amount are required.

[0006] For example, as shown in FIG.
4 of the three-phase signals _{(v a, v b, v} c) a 3-phase transformer 611
A three-phase full-wave rectifier circuit composed of a semiconductor 612 resistor 613 and a capacitor 614 converts the signal into a low-level analog signal and corrects the characteristic with an adjusting resistor 615. Similarly, the active power converter, the V / HZ converter, and the reactive power converter are similarly converted into small-level analog signals by a circuit including a semiconductor, a capacitor, and a resistor. The characteristic adjustment of these converters is corrected by variable resistors.

[0007]

Since the conventional excitation control device is configured as described above, the AVR 6 and the input signal converter of the additional function device are required respectively, and the converter is a semiconductor and a capacitor. In addition, since the circuit is constituted by resistors and the like, there is a characteristic difference inherent to the circuit element and a response delay due to a time constant of a capacitor, a resistor, and the like, and it is difficult to obtain ideal control. In addition, various converters must be provided in a limited space factor along with the small size of the control panel, resulting in deterioration in heat dissipation and maintenance.

This invention has been made in order to solve the above-mentioned problems, and does not provide input signal converters, but controls the input of PT4 and CT5 by one digital converter to control the excitation controller. It is an object of the present invention to provide a device capable of producing all of an input signal generator voltage (V), an active power (P), a voltage / frequency ratio (V / F), and a reactive power (Q) necessary for the above.

[0009]

SUMMARY OF THE INVENTION An excitation control device according to the present invention comprises an automatic voltage regulator for controlling the voltage of a synchronous machine to be constant, and controls the excitation of the synchronous machine. And input signals of an instrumentation transformer (PT) and an instrumentation transformer (CT) for detecting current,
Generator voltage, frequency, and electric power necessary for excitation control
Flow, comprising a active power, digital converter to create the software calculating all signals of the reactive power, the digital
The converter is an isolator that isolates the input signal,
High-speed operation unit for operation, 2-port register for operation processing
Bus and PIO bus-in that outputs each signal for control
It is composed of a surface.

[0010]

The signals of the input signals (V, P, V / F, Q) necessary for the control of the excitation control device in this invention are converted by one digital converter and used as input signals for the excitation control.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 3, reference numeral 20 denotes a digital converter for converting the signals of PT4 and CT5 into generator voltage (V), active power (P), voltage / frequency ratio (V / F), and reactive power (Q). .

FIG. 4 shows the hardware configuration of the digital converter. The digital converter is composed of a single print card, and the three-phase input signals (v, PT4, CT5) are internally provided.
_{a, v b, v c,} i a, i b, isolator 201 to isolate the i _c), PT4, the signal for controlling from the 3-phase signal CT5 (V, P, V / F, Q) and It comprises a high-speed operation unit 202 for performing operations, a two-port register 203 for operation processing, and a PIO bus interface 204 for outputting signals (V, P, V / F, Q) for control.
Next, a software operation method in the high-speed operation unit will be described.

[0013] One cycle of v _a AC signal which is one of the example PT3 phase signal as shown in FIG. 5 by circumferential 12 minutes samples. FIG. 6 shows the details of the operation formula of each input signal, and the operation is 2
One of the sampling data (v _am and v _am-3) than with the product form of the amplitude value calculation equation v _a value calculated 3-phase (v _a, v _b, v
_The voltage (V) is obtained from the average value of _c ). The current (I), active power (P), frequency (F), and reactive power (Q) are calculated in the same manner. By performing input signal conversion by digital control (soft operation) in this manner, characteristics can be made uniform, and performance and accuracy can be improved. The response speed of the input signal conversion is increased from several hundred milliseconds in the past to ten and several milliseconds. In addition, since the digital converter is constituted by a single printed circuit board, the digital converter requires less space factor than the conventional one, so that the maintenance space and the like are increased.

In the above embodiment, the exciter 3 is a rotary exciter having a gain and a first-order lag characteristic. However, a static exciter in which the first-order lag is almost negligible may be used. Further, in the above embodiment, the voltage 3
Although three-phase and three-phase current signals are used, single-phase or only two-phase signals or a combination thereof may be used, and the same effects as in the above-described embodiment can be obtained.

[0015]

As described above, according to the present invention, since the input signal conversion is performed by digital control (soft operation), the response due to the characteristic difference inherent in circuit elements such as semiconductors, capacitors, resistors and the like and the time constant. The delay of
Characteristics can be standardized, and performance and accuracy can be improved. In addition, since the digital converter can be constituted by one printed circuit board, the space factor is small and the maintenance space has a margin.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a conventional excitation system.

FIG. 2 is an internal view of a conventional voltage detector.

FIG. 3 is a configuration diagram of an excitation system according to an embodiment of the present invention.

FIG. 4 is an internal configuration diagram of a digital converter.

Figure 5 shows an example of sampling the waveform of v _a signal which is one of PT3 phase signal.

FIG. 6 shows a high-speed calculation (software calculation formula) in the digital converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synchronous machine 2 Field winding 3 Exciter 4 Instrument transformer 5 Instrument transformer 6 Automatic voltage regulator

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-344199 (JP, A) JP-A-60-197194 (JP, A) JP-A-61-185100 (JP, A) JP-A 64-64 81700 (JP, A) JP-A-56-22600 (JP, A) JP-A-59-169394 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02P 9 / 00-9 / 48

Claims (1)

(57) [Scope of request for utility model registration] 1. An excitation control device for a synchronous machine, comprising: an automatic voltage regulator for controlling the voltage of the synchronous machine at a constant level, for controlling excitation of the synchronous machine. The respective signals v and i of the instrument transformer (PT) and the instrument transformer (CT) are inputted, and the generator voltage V, frequency F, current I, and effective voltage necessary for the excitation control are inputted.
The following formula is used to calculate all signals of force P and reactive power Q
Digital created by software operation
Digital converter, the digital converter converts the input signal.
Isolator to insulate, high-speed operation unit to calculate each signal,
2 port register for arithmetic processing and control
Consists of a PIO bus interface that outputs each signal
An excitation control device for a synchronous machine, comprising: (Equation 1) _{However, v a, v b, v} c is the 3-phase input signals of the PT, respectively
No. a and, v _am is by 12 dividing the one period of v _a ac signal
It is the signal value at one time when sampling,
v _am-3 is the signal value at the time when the phase is delayed by π / 2 from v _am , v
_am-6 is the signal value when the phase is delayed by π from v _am . v
_bm , v _bm-3 , v _bm-6 , and v _cm , v _cm-3 , v
The same applies to the relationship of _cm-6 . Also, i _a ,
i _b, i _c is the 3-phase input signals CT, respectively, i _am
Is sampled by dividing one cycle of the _ia AC signal by 12
A signal value at one time point when the, i _am-3 is i _am
Signal value when the phase is delayed by π / 2, i _am-6 is greater than i _am
This is the signal value when the phase is delayed by π. i _bm , i _bm-3 , i
relationship of _bm-6, as well as i _cm, with the relationship of _{i cm-3, i cm-} 6
This is the same as above.