JP2521130B2 - AC excitation synchronous machine control system - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

This invention is an AC excitation synchronous machine (hereinafter referred to as AE
The present invention relates to a control system for an AC excitation synchronous machine that performs rotation speed control and power control in a variable speed pumped storage power generation system to which an SM (abbreviated as SM) is connected.

[Prior art]

FIG. 3 is, for example, in the magazine, Vol. 107, No. 3, p. 210, p. 210,
FIG. 13 is a block diagram of a variable speed pumped storage hydropower system showing the conventional AESM control system shown in FIG.
Is an AESM in which the secondary side of a wound-type induction motor is secondarily excited by a cycloconverter and is operated at a specified power at a variable speed, 2 is a pump turbine directly connected to the AESM1, 3 is A
Generator breaker for cutting off generated power P of ESM1, 4 cycloconverter, 5 automatic current controller, 6 load regulator, 7 output setter of generated power P, 8 input / output control servo of pump turbine , 9 is the governor of the generator, 10 is the rotation speed calculation unit, 11 is the valve opening calculation unit of the guide vane, P, N, H and GVO are the actual power generated by AESM1, the rotation speed, and the head of the pumped storage power generation system. , Guide vane opening, etc. Next, the operation will be described. First, in order to operate the AESM1 at a variable speed, a method of secondarily exciting the AESM1 is usually adopted. Therefore, even if the rotation speed N changes, the system frequency f
The frequency is corrected by the secondary excitation by the amount of slip so as to match with, and parallel operation with the system is enabled. That is, as the frequency conversion device, a cycloconverter system that directly converts alternating current into alternating current is usually used. Therefore, the cycloconverter 4 is controlled by controlling the output setter 7, the load adjuster 6 and the automatic current controller 5 so that the electric power 65P set by the output setter 7 is obtained. on the other hand,
The output setting device 7 so that the pump turbine 2 has the optimum rotation speed N _0.
Rotation speed calculation unit 10, governor 9, guide vane valve opening calculation unit 11 perform optimum calculation for the set values of, respectively, determine guide vane opening GVO, and finally input / output control servo 8
Control to operate AESM1 to the optimum value. Here, if the system of FIG. 3 is subjected to disturbance and the set value 65P of the output setter 7 for the next generation is operated to increase,
In the case of power feedback, generated power P is output setter 7
However, since the guide vane operation is slow, deceleration torque acts on the rotating body, and the number of revolutions N decreases primarily. After that, the rotation speed N increases and settles to an optimum value as the guide vane is opened by the calculation of the valve opening calculation unit 11. On the other hand, the followability of the generated power P is fast, but the settling of the rotation speed N is slow and the motor temporarily operates in the opposite direction.

[Problems to be Solved by the Invention]

Since the conventional AC excitation synchronous machine control system is configured as described above, when the output setting device 7 is operated next in the power generation operation, the electric power P is supplied to the cycloconverter 4 electrically by the external output setting device 7. However, since the guide vane operation is mechanical and slow, the rotation speed N may temporarily respond in the opposite direction, and since the fast control is fed back to the cycloconverter 4 with electric power, the electric power is constant. Therefore, the stability of the governor loop is deteriorated, and the rotation speed may deviate from the variable speed range. The present invention has been made to solve the above problems, and speeds up the integral time of the electric power or the rotation speed by switching the control circuit of the cycloconverter according to the operational need of the pumped storage power plant. Along with the prevention of temporary overshooting of the rotation speed to stabilize the system, the energy of the rotating body is temporarily released to reduce the rotation speed, but the AC excitation synchronous machine that works effectively as an instantaneous reserve of electric power. The purpose is to obtain a control system.

[Means for Solving the Problems]

The control system of the AESM according to the present invention inputs the rotation speed deviation signal to the cycloconverter to give immediate response,
Rotational speed feedback control by rotational speed deviation control to settle the rotational speed, or power deviation control to input power deviation signal to the cycloconverter and settling power quickly, depending on the operational need, The switching circuit is switched and controlled by a judgment signal of the switching judgment circuit.

[Action]

The control system of the AESM according to the present invention is provided with a switching circuit capable of selecting either control based on power deviation or control based on rotational speed deviation for control of the cycloconverter, and control of either electric power or rotational speed feedback control based on the judgment of the switching judgment circuit. Select the method to switch and control.

Examples of the invention

An embodiment of the present invention will be described below with reference to the drawings. In the figure, the same parts as in FIG. 3 are shown with the same reference numerals, and in FIG. 1, 12 and 13 are switching circuits for rotation speed deviation control and power deviation control. In the switching circuits 12 and 13 that are switched in conjunction with each other by a switching determination circuit 15 to be described later, in the figure, the upper side is connected to the rotation speed deviation control and the lower side is connected to the power deviation control. 14 is a rotation speed detector, 15 is a switching judgment circuit, 16
Is a system data transmission unit, and 17 is a power generation / pumping command circuit. Further, while the control of the cycloconverter 4 is conventionally performed by electric power feedback, in the case of the present invention, the control of the cycloconverter 4 can perform switching control of electric power feedback and rotation speed feedback by the designation of the switching judgment circuit 15. I am trying. Next, the operation of the present invention will be described. First, the rotational speed deviation control will be described. A description will be given of a case where the rotation speed feedback method of the present invention is used as the excitation system control method of the cycloconverter 4 in contrast to the conventional power feedback method. Both control methods settle in the same optimum operating state in the steady state, but operate as follows in the transition immediately after the disturbance. That is, when the rotation speed feedback circuit according to the present invention is used, the rotation speed N rises according to the optimum function output, as shown in FIG. In order to supply the energy for the speed increase of the rotating body from the prime mover, the generated electric power P is temporarily reduced, and thereafter, the generated electric power P is opened together with the guide vane opening operation.
Increases and settles to the set value. In proportion to the conventional method, the rotation speed is settled quickly, there is no reverse operation, and the power settles down at the same time as the rotation speed is settled. Therefore, it is better to use the rotation speed feedback during normal power generation operation. On the other hand, for pumping control, the generated power
Since the change in P _{m and} the change in the rotation speed N are in the same direction, the response speed of each can be increased. Therefore, in order to contribute to the system stability, the same power feedback method as the conventional one is adopted. At that time, the switching determination circuit 15 outputs a switching signal so that the switching circuits 12 and 13 are tilted downward. However, even when power is being generated, when used as an emergency reserve in the event of a system accident, etc., power priority control is superior, and even during power generation, an emergency command is received from the system data transmission unit 16 and the switching determination circuit 15, Rotational speed feedback control, that is, switching circuits 12 and 13
Is switched from the upper side to the lower side power feedback control for temporary operation, or when there is a risk that the rotation speed N can be controlled by the cycloconverter 4 even during pumping operation and the operation exceeds the lower limit. Is controlled by switching from electric power feedback to rotational speed feedback by the rotational speed detector 14 and the switching judgment circuit 15. Further, in the above embodiment, the control of the cycloconverter has been described in the case of the power feedback and the rotation speed feedback. However, a rotation speed correction circuit may be added to the power feedback, or a power correction circuit may be added to the rotation speed feedback. Alternatively, only the variable speed power generation may be used, and another conversion method such as a double-sided forced commutation type shared voltage type converter (GTO) may be used instead of the cycloconverter, and the same effect as that of the above-described embodiment is obtained.

【The invention's effect】

As described above, according to the present invention, the rotation speed of the AC excitation synchronous machine during the pumping operation is the cycloconverter based on the output signal from the rotation speed detector, the power generation, the pumping command circuit, and the command from the system data transmission unit. Controllable, and when there is a risk of operating above the lower limit or during normal power generation operation, switch to rotation speed feedback control, and during pumping operation switch to switching feedback command to switch to power feedback control Since it is configured to have a judgment circuit, it is possible to switch between the rotation speed feedback control and the power feedback control according to the operating state, and if necessary, the responsiveness of either the rotation speed or the power can be made faster. There is an effect that a control system of an AC excitation synchronous machine that can be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control system of an AESM according to an embodiment of the present invention, FIG. 2 is a response characteristic diagram when the cycloconverter control of the present invention is a rotation speed feedback, and FIG. 3 is a conventional AESM. FIG. 4 is a block diagram showing a control system, and FIG. 4 is a response characteristic diagram when the conventional cycloconverter control is used as electric power feedback. 1 is an AC excitation synchronous machine (AESM), 2 is a pump turbine, 4 is a cycloconverter, 7 is an output setting device, 12 and 13 are switching circuits, 14 is a rotation speed detector, 15 is a switching judgment circuit, and 16 is system data. Transmission part, 17 is a power generation and pumping command circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. An AC exciter synchronous machine is directly connected to a pump turbine, and a secondary side of the AC exciter synchronous machine is secondarily excited by a cycloconverter to perform power control operation at a variable speed based on a command from an output setting device. In the control system of the AC excitation synchronous machine, a switching circuit for switching the control of the cycloconverter to either rotation speed deviation control or power deviation control, and a rotation speed detector for detecting the rotation speed of the AC excitation synchronous machine,
Based on the output signal from the rotation speed detector, power generation, a pumping command circuit, and a command from the system data transmission unit, the rotation speed of the AC excitation synchronous machine during pumping operation exceeds the controllable upper and lower limits of the cycloconverter. It is equipped with a switching judgment circuit for instructing the switching circuit to switch to rotation speed feedback control during normal power generation operation and to switch to power feedback control during pumping operation. Characteristic AC excitation synchronous machine control system.