JPH04308364A - Speed governing control systme for hydraulic power plant - Google Patents

Abstract

PURPOSE:To improve controllability on the speed and output of a generator and simplify maintenance by detecting the guide vane opening of a hydraulic turbine without requiring a wire and a wire mechanism part, and a differential transformer and a differential transformer conversion part. CONSTITUTION:The guide vane opening 13 of a hydraulic turbine is computed from the output of a resolver 7 fitted to the anti-load side of an AC servo motor 6 serving as the prime mover of a motor-driven servo motor 8, and fed back to a governor regulator 4.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed governor control system for a hydroelectric power plant that controls the speed and output of a generator by opening and closing guide vanes of a water turbine of the hydropower plant using an electric servo motor.

0002

2. Description of the Related Art In a speed regulating control system for a hydroelectric power plant, a servo motor drives and controls guide vanes that regulate water flowing into a water turbine. The servo motor for operating the guide vanes of this water turbine is generally driven by hydraulic operation, but since it is a hydraulic mechanism, it requires many attached devices such as a pressure oil pump set, pressure oil tank, piping, and valves. I need. Therefore, simplification is desired from the viewpoint of maintenance as well. In recent years, oil spills into rivers have become an important environmental problem.

[0003] Therefore, electric servo motors have been adopted in order to solve the problems of these accessory devices and to simplify the equipment. In a system using this electric servo motor, the electric servo motor is controlled by a speed command from a governor regulator, and the opening degree of the guide vane of the water turbine is controlled.

[0004] The basic control object of the governor regulator is the speed and output of the water turbine generator. The speed of the water wheel is detected by an electromagnetic pickup, and the position of the servo motor that moves the guide vanes is detected by a differential transformer or potentiometer.

FIG. 3 is a block diagram of a conventional speed governor control system. The speed of the generator 1 is detected by an electromagnetic pickup and inputted to the governor regulator 4. Further, the position of an electric servo motor 8 that moves a guide vane 3 for adjusting the amount of water flowing into the water turbine 2 is detected by a differential transformer 9 and input to the governor regulator 4 . The governor regulator 4 performs PID calculation based on these signals to keep the regulation rate or drooping rate constant. Then, a position command for the electric servo motor 8 is calculated, and a speed command 11 given to the servo amplifier device 5 is adjusted in order to control the position of the electric servo motor 8 based on this command. The servo amplifier device 5 issues a command to the electric servo motor 8 via the AC servo motor 6, and the rotor position of the AC servo motor 6 is detected by the resolver 7 and sent to the servo amplifier 5.
is input.

FIG. 4 is a block diagram of the servo amplifier device 5. As shown in FIG. A speed command 11 from the governor regulator 4 is input to a speed control section 15 of the servo amplifier device 5. The speed control section 15 uses this speed command 11 and the resolver control section 25.
A current command 19 is calculated by comparing the current command 19 with the motor speed 20 from the current control section 24 . The current control unit 24 compares the current command 19 and the load current 28 and outputs a control signal 23 to flow a sine wave current that matches the rotor position 21 obtained from the output 27 of the resolver 7 via the resolver control unit 25.
is output to the inverter section 22. The inverter section 22 generates an alternating current voltage 26 of a necessary frequency based on the control signal 23, and drives the AC servo motor 6.

[0007] Here, the inverter section 22 includes an AC power source 1
DC 1 obtained by converting AC from 0 to DC in the converter section 14
8 is input. Further, the sequence control unit 16 performs not only speed regulating control of the generator 1 but also sequence control of the entire generator 1 based on the operation command 12.

[0008] As a result, the electric servo motor 8 is driven to operate the guide vane 3, and the flow rate proportional to the guide vane opening generates acceleration torque to the water turbine 2, which generates electricity by balancing with the load of the generator 1. Machine 1 is accelerated or decelerated.

[0009]

[Problems to be Solved by the Invention] However, in order to control the speed and output of the generator as described above, feedback of the speed of the generator and the opening degree of the guide vane is required. To detect this, a wire is attached to the end fitting of the electric servo motor 8, and the differential transformer is rotated by this wire. On the other hand, on the governor regulator 4 side, the AC excitation voltage is transferred to the differential transformer 9
In addition, it is necessary to convert the secondary side signal proportional to the guide vane opening into a DC voltage proportional to the opening position via a synchronous rectification and filter circuit. The electric servo motor 8 is used to simplify maintenance, improve controllability, and reduce construction costs by not using control oil. Since a transformer is used, errors due to elongation of the return wire, friction with the wire mechanism, aging, etc. become a problem.

[0010] Also, in addition to the differential transformer, a converting section for the differential transformer is also required, which is not preferable. The same applies if a potentiometer is used instead of a differential transformer.

Therefore, an object of the present invention is to detect the opening degree of a guide vane of a water turbine without requiring a wire, a wire mechanism, a differential transformer, or a differential transformer converter, and to detect the speed and output of a generator. An object of the present invention is to provide a speed regulating control system for a hydroelectric power plant that can improve controllability and simplify maintenance. [Structure of the invention]

0012

[Means for Solving the Problems] The present invention provides a resolver that is attached to the opposite load side of an AC servo motor, which is a prime mover of an electric servo motor, and that detects the rotor position of the AC servo motor, and a resolver that controls the drive of the AC servo motor. At the same time, there is a servo amplifier device that calculates the position of the electric servo motor based on the rotor position signal of the AC servo motor from the resolver and calculates the guide vane opening, and the guide vane opening calculated by this servo amplifier and power generation. It is equipped with a governor regulator that issues control commands to the servo amplifier device based on the speed of the machine.

[0013]

[Operation] In the present invention, the position of the electric servo motor is detected by a servo amplifier device from the signal of the rotor position of the AC servo motor, which is the output of the resolver that is essential for controlling the AC servo motor. The guide vane opening degree is calculated from the ratio to the total stroke and fed back to the governor regulator.

[0014] Therefore, a wire, a wire mechanism, a differential transformer, or a differential transformer converter are not required for detecting the opening of the guide vane of a water turbine.

[0015]

[Embodiment] An embodiment of the present invention will be described below. FIG. 1 is a configuration diagram of a speed governor control system according to an embodiment of the present invention. In this figure, the same parts as those in FIG. 3 are given the same reference numerals, and the explanation will be omitted. The difference in this figure is that the guide vane opening degree 13 of the water turbine 2 is fed back from the servo amplifier device 5 to the governor regulator 4, thereby eliminating the need for the differential transformer 9. That is, in order to control the speed and output of the generator 1 based on the frequency command and the output command, the governor regulator 4 detects and inputs the speed of the generator 1 using an electromagnetic pickup, and also controls the guide vane opening 13 using a servo. It is input from the amplifier device 5.

FIG. 2 is a block diagram of a servo amplifier device according to an embodiment of the present invention, and the same parts as those in FIG. 4 are given the same reference numerals and the explanation thereof will be omitted. The difference in this figure is that the guide vane opening degree 13
The purpose is to detect

That is, the guide vane opening degree 13 is calculated by detecting the position of the electric servo motor 8 that moves the guide vane 3. The rotor position 21 calculated by the resolver control unit 25 is determined by the amount of movement of the electric servo motor 8, that is, the position is calculated, and the guide vane opening degree 13 with respect to the position of the electric servo motor 8 is calculated from the ratio with the number of pulses of the total stroke of the electric servo motor 8.

The guide vane opening degree 13 is then fed back to the governor regulator 4. Based on this signal, the governor regulator 4 performs PID calculation to keep the regulation rate or drooping rate constant, and the electric servo motor 8
Based on this command, the command given to the servo amplifier device 5 is adjusted to control the position of the electric servo motor 8.

According to this command, the servo amplifier device 5
The C servo motor 6 is driven, and the electric servo motor 8 operates the guide vane 3. And guide vane 3
Accelerating torque to the water turbine 2 is generated by the flow rate proportional to the opening degree of the generator 1, and the generator 1 is accelerated or decelerated depending on the balance with the load of the generator 1.

The servo amplifier device 5 is equipped with a DC backup power source in addition to the normal AC power source, and the A
Control is possible even if the C power supply runs out. If the DC backup power supply also disappears, it will be impossible to detect the opening of the guide vane 3, making it impossible to control it, but in such a case, there will be a problem because the guide vane 3 is designed to automatically close. There isn't. Additionally, if such an accident occurs and the engine is restarted, there is a possibility that the opening degree of the guide vane 3 cannot be calculated accurately, so it is necessary to initialize the guide vane opening degree 13 with a fully closed signal of the guide vane 3. be. In this way, even if an accident occurs, the opening degree of the guide vane 3 can be accurately detected even under normal conditions.

As described above, the position of the electric servo motor is detected from the signal of the rotor position of the AC servo motor, which is the output of the resolver which is essential for controlling the AC servo motor, and the entire stroke of the electric servo motor is determined. The speed and output of the generator can be controlled by calculating the guide vane opening degree from the ratio and feeding it back to the governor regulator.

[0022] This eliminates the need for the return wire, the rear part of the wire machine, the differential transformer, the differential transformer converter, etc. that were conventionally used to detect the opening of the guide vane.

[0023]

[Effects of the Invention] As described above, in the speed governing control system of the present invention, return wires, wire mechanisms, differential transformers, and differential transformer converters are not required.
Equipment can be simplified and reliability improved. In addition, since aging changes such as wire elongation are eliminated, maintainability can be further simplified and controllability can be improved. This further increases the merits of applying the electric servo motor.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram of a servo amplifier device of the present invention.

FIG. 3 is a block diagram of a conventional example.

FIG. 4 is a block diagram of a conventional servo amplifier device.

[Explanation of symbols]

1 Generator 2 Water wheel 3 Guide vane 4 Governor regulator 5 Servo amplifier 6 AC servo motor 7 Resolver 8 Electric servo motor 9 Differential transformer 10 AC power supply 11 Speed command 12 Operation command 13 Guide vane opening degree 14 Converter section 15 Speed control section 16 Sequence control section 17 Opening detection part 18 DC power supply 19 Current command 20 Motor speed 21 Rotor position 22 Inverter section 23 Control signal 24 Current control section 25 Resolver control section 26 AC voltage 27 Resolver output 28 Load current

Claims (1)

[Claims] Claim 1: In a speed governing control system for a hydroelectric power plant in which a guide vane of a water turbine of a hydroelectric power plant is opened and closed by an electric servo motor to control the speed and output of a generator, the motor is a prime mover of the electric servo motor. a resolver that is attached to the opposite load side of the AC servo motor and detects the rotor position of the AC servo motor; a servo amplifier device that calculates the position of the servo motor and calculates the opening degree of the guide vane, and a governor regulator that issues a control command to the servo amplifier device based on the guide vane opening degree calculated by the servo amplifier device and the speed of the generator. A speed regulating control system for a hydroelectric power plant, characterized by comprising: