JP5412727B2 - Automatic voltage control method at and after generator voltage establishment - Google Patents

Description

  The present invention relates to a digital automatic voltage control apparatus for a turbine generator, and more particularly to an automatic voltage control method at the time of establishing a voltage of a generator and after the establishment.

  A control block configuration as shown in FIG. 4 is used for automatic voltage control of the turbine generator. In FIG. 4, reference numeral 1 denotes a turbine (T), and a field current is supplied to an excitation winding of a generator 2 driven by the turbine 1 by an excitation device 3 composed of a thyristor control unit.

  Reference numeral 4 denotes a digital automatic voltage control device (hereinafter referred to as AVR). The AVR 4 converts the generator voltage detected by the transformer PT into a digital signal by the A / D converter 5 and an effective value converter (not shown). Is converted into an effective value by adjusting the phase advance / delay by the power fluctuation stabilizing device 6, and the deviation from the voltage setting device 7 consisting of 90 R is obtained by the deviation device 8, and then the deviation is subjected to voltage control calculation with a limiter. The unit (first LPI) 9 performs a proportional integration (PI) calculation to obtain a field current command.

  The changeover switch 10 switches the field current command from the first LPI 9 and the field current command from the 70E field current setter 11. Reference numeral 12 denotes an A / D converter that detects a field current If supplied from the excitation device 3 to the excitation winding of the generator 2, and this A / D converter 12 digitally detects the detected current from the current transformer CT. The signal is converted into a signal, and the field current command and the field current If converted into a digital signal are supplied to the deviation unit 13.

  The deviation between the field current command and the field current If is obtained by the deviator 13, and the deviation is proportional-integral (PI) computed by the limiter-equipped field current control computation unit (second LPI) 14. This calculation result is converted into an analog signal by the D / A converter 15 and used as an excitation control signal for a gate circuit (not shown), and the phase control of the thyristor of the excitation device 3 is performed by the gate circuit.

In the above configuration, the selector switch 10 is set to the field current setter 11 side to perform the initial excitation of the generator 2, and then the selector switch 10 is switched to the first LPI 9 side to perform automatic voltage control of the generator 2. The field current is automatically controlled so that the generated voltage of the generator 2 matches the set voltage (rated voltage) of the voltage setter 7.
JP-A-11-150994

  There are two methods of controlling the voltage establishment of the turbine generator: separately excited and self-excited. Currently, the separately excited method is mainly used. In the case of the separate excitation method, when the “field breaker # 41 (excitation)” signal is turned ON, the thyristor control unit turns ON “# 41I (initial excitation)” and performs control based on an external command. When the generator voltage becomes equal to or higher than the set value (equivalent to about 80% of the rated value), “# 41I” is turned OFF, and control is performed according to a command from AVR4.

  For this reason, AVR4 is in an open loop until “# 41I” is turned off from “# 41” being turned on, which is the same as the uncontrolled state, and the integral term of the first LPI 9 shown in FIG. .

  Therefore, when the control is changed to AVR4, there is a problem that the generator voltage control is not stable and causes overshoot / undershoot. In addition, there is a problem in that the response of control during normal operation is lowered if the gain is decreased in order to stabilize the first LPI 9 when the generator voltage is established.

  The present invention has been made in view of the above circumstances, and at the time of establishment and establishment of a generator voltage that is intended to stabilize control after establishment of the generator voltage and to prevent overshoot and undershoot. It is an object of the present invention to provide a later automatic voltage control method.

In order to solve the above problems, the present invention provides a voltage control calculation unit that obtains a field current command by a proportional integral calculation of a deviation between a detection voltage of a turbine generator and a set value of a voltage setter, A field current control calculation unit for controlling a field current of the generator according to a deviation between the field current command and a detected field current of the generator; The generator voltage is increased by the set value of the field current setter that performs field current control only by the magnetic current control calculation unit, and after the voltage rises, it is automatically switched to the field current command from the voltage control calculation unit. In the turbine generator automatic voltage control method in which the voltage is controlled at the same time, it is determined whether or not the generator voltage is equal to or higher than a set value, and the field current setting device is set until the voltage reaches the set value. The value depends on the output of the field current increase change processing unit. Furthermore, until the voltage of the generator is established, the field current is linearly increased. When the voltage target value is reached, the field current command is switched from the voltage control calculation unit, and the generator is connected to the calculation unit. The field current increase change processing unit is composed of an internal automatic calculation processing unit and a switch, and the internal automatic calculation processing unit An increase per hour is added to the set value of the current setting device.

  According to the present invention, the control at the time of establishing the generator voltage is stabilized, overshoot / undershoot can be prevented, and the control after the generator voltage is established can be controlled stably, and each set value is variable. This enables stable control regardless of the type of generator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same parts as those in FIG. In FIG. 1, when the changeover switch 10 is switched to the manual side and controlled until the generator voltage becomes equal to or higher than the set voltage, the set value of the field current setter 11 is changed, and the field current is changed to the target value. Control is performed using the value from the field current increase change processing unit 20 that linearly increases at the set time.

  The field current increase change processing unit 20 includes an internal automatic calculation processing unit 21 and a switch 22, and the internal automatic calculation processing unit 21 adds an increase per time to the set value of the field current setter 11. Is. The deviation between the added value and the field current If is obtained from the deviator 13, the deviation is controlled by the second LPI 14, and the generator winding is excited from the IGBT controller 3 a via the D / A converter 15. Supply to the line and establish the generator voltage.

  When the generator voltage is established, the changeover switch 10 of the AVR 4 is switched to the automatic side, and control is performed from the first LPI 9. At this time, the field current If is supplied from the A / D converter 12 to the first LPI 9, and the integral term of the first LPI 9 is set to the field current detection value. This prevents overshoot / undershoot from occurring when the AVR 4 automatically switches.

  FIG. 2 is an operation flowchart of the above embodiment. It is determined whether the field breaker # 41 is ON in step S1, and if “Yes”, it is determined in step S2 whether the generator voltage is equal to or higher than the set value. If “No”, the process proceeds to step S3. In step S <b> 3, the increment per hour from the internal automatic calculation processing unit 21 is added to the set value of the field current setter 11. This increment is the upper limit value of the field current setter 11 × the calculation cycle / the set time.

  If the field current increases linearly and reaches the target value as shown in FIG. 3A in the process of step S3, the process proceeds to step S4. Step S4 is a process of setting the first LPI 9 operation integral term to the field current detection value. By performing this process, the voltage overshoots as shown in FIG. 3B. It becomes possible to control without overshooting as shown in FIG. The process of step S4 returns to step S2 again, where it is determined whether or not the voltage is equal to or higher than the set value. If “Yes”, the normal calculation process of step S5 is performed and the process ends.

The block block diagram which shows embodiment of this invention. The operation | movement flowchart of embodiment. (A) is a waveform diagram in which the field current reaches the target value linearly at a set time, (b) is a waveform diagram when there is an overshoot, and (c) is a waveform diagram when no overshoot occurs. The block block diagram of a prior art example.

Explanation of symbols

5 ... A / D converter for voltage detection 7 ... Voltage setter 9 ... Voltage control operation unit with limiter (first LPI)
DESCRIPTION OF SYMBOLS 10 ... Changeover switch 11 ... Field current setting device 12 ... A / D converter for field current detection 14 ... Field current control calculation part with a limiter (2nd LPI)
DESCRIPTION OF SYMBOLS 15 ... D / A converter 20 ... Field current increase change process part 21 ... Internal automatic calculation process part 22 ... Switch

Claims (1)

A voltage control calculation unit that obtains a field current command by proportional integral calculation of a deviation between a detected voltage of the turbine generator and a set value of the voltage setting unit, and a deviation between the field current command and the detected field current value of the generator A field current control calculation unit that controls a field current of the generator according to the field current, and a field current setter that performs field current control only by the field current control calculation unit when the voltage of the generator is established In the automatic voltage control method for a turbine generator, the voltage of the generator is increased according to the set value, and after the voltage increase, the voltage is automatically controlled by switching to the field current command from the voltage control calculation unit.
It is determined whether the generator voltage is equal to or higher than the set value, and the set value of the field current setter is changed by the output of the field current increase change processing unit until the voltage reaches the set value. Until the voltage is established, the field current is increased linearly and when the voltage target value is reached, the field current command from the voltage control calculation unit is switched to the field current detection value of the generator in the calculation unit. Is repeatedly performed as control calculation output,
The field current increase change processing unit is composed of an internal automatic calculation processing unit and a switch, and the internal automatic calculation processing unit adds the increment per time to the set value of the field current setting device. An automatic voltage control method during and after the establishment of the generator voltage.

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