JPH05336800A - Controlling equipment of power of winding type induction machine - Google Patents

Abstract

PURPOSE:To prevent a sudden change of an effective power by a method wherein a speed deviation is made zero substantially for following by adding a certain bias signal to a speed target signal before parallel and the bias signal is made zero little by little after the parallel. CONSTITUTION:A speed instruction signal Na outputted by a speed instruction preparing part 15 and a speed signal N undergo transition in a state of being in accord substantially with each other, from a time t1. The speed instruction signal Na is outputted to an adder-subtracter and added up to the speed signal N, a deviation signal thereof becomes zero substantially, and the condition of parallel its established at a time t2. In this case, a signal obtained by addition of a bias signal B and a value of zero of a fixed value setting unit 19 is inputted to an integrator 16, an output of the integrator 16 attenuates from the value of the bias signal B before the parallel to the value of zero by a prescribed time constant of linear delay and the bias signal B becomes zero at a time t4. According to this constitution, the speed instruction signal is prevented from changing stepwise after the parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power control apparatus for a wound-rotor induction generator, and more particularly to a power control apparatus for a wound-rotor induction machine that suppresses fluctuations in active power in parallel.

[0002]

2. Description of the Related Art In a conventional pumped-storage power plant, since a synchronous machine is used as a generator motor, the rotation speed is constant at the synchronous speed. Therefore, during power generation operation, the guide vane opening is also determined when the head is determined from the active power, but the operating state at that time is not always efficient as a pump turbine. Also, during pumping operation, the input becomes constant once the pump head is determined,
Unable to control active power.

A variable speed pumping system detects the rotational speed and phase of the rotor of a wire wound induction machine and outputs the output frequency and phase of a frequency converter for exciting the secondary side of the wire wound induction machine with a low frequency AC. Is a system in which the primary side can always be synchronized with the system even if the rotor of the wire-wound induction machine is not at the synchronous speed. That is, it is a system that can change the rotation speed during system parallelization.

In this system, the active power, the guide vane opening degree, and the rotation speed can be manipulated so that the pump turbine always operates with high efficiency during the power generation operation. Further, during the pumping operation, the active power changes with the cube of the rotation speed, so the active power can be adjusted by changing the rotation speed.

FIG. 4 is a block diagram showing a conventional example in a parallel state. In the figure, the rotor 1a of the wire wound induction machine 1 and the pump turbine 2 are directly connected to each other, and these are rotated by the flow rate from the guide vanes 3. The rotor 1a is excited by an alternating current by the frequency converter 4, while its current is detected by the current detector 5 and the number of rotations is detected by the speed detector 6. The stator 1b of the wound-rotor induction machine 1 is connected to a system 8 via a parallel circuit breaker 7, and the system 8 includes an active power detector 9
Are connected.

The active power controller 10 uses the active power command output from the active power command setter 11 and the active power output from the active power detector 9 for detecting active power to be input to the grid, and the head of the pump turbine. The guide vane opening command and the speed command are output so that the No. 2 operates at high efficiency. Speed controller 1
The current controller 13 outputs the output current command of the frequency converter 4 from the speed command signal Na and the speed signal N which is the output of the speed detector 6 so that the rotation speed of the wire wound induction machine 1 is in accordance with the command value. Output to. The current controller 13 controls the output current of the frequency converter 4 from the output current command and the output of the current detector 5 which detects the output current of the frequency converter 4.

During the power generation operation, the input of the pump turbine 2 is changed by adjusting the flow rate by opening and closing the guide vanes 3, and the input becomes the power generation amount of the wire wound induction machine 1 and outputs it to the system 8. Further, during the pumping operation, the pump-turbine 2 is rotated by the active power input from the system by the wound-rotor induction machine 1 to pump water. Reference numeral 14 represents an adder / subtractor.

[0008]

However, the above-mentioned device has a problem that the active power changes abruptly in parallel.

That is, since the frequency and phase of the primary side before parallelization are synchronized with the grid, there is no power exchange with the grid at the moment of parallelization, but the active power that becomes the speed command signal after parallelization is It is a rotation speed that makes the pump turbine 2 highly efficient, and is different from the speed before the parallel connection. Therefore, after parallel connection, the speed command signal Na and the speed signal N from the active power controller 10
Are input to the speed controller 12, and the speed controller 12 multiplies the speed deviation signal by a proportional gain to output the current controller 13 to the frequency converter 4.
As a result, the suddenly changed signal causes the output current of the frequency converter 4 to suddenly change.

For example, referring to FIG. 5, it is assumed that the speed signal N and the speed command signal Na change from time t1 as shown in the figure, and the parallel condition is satisfied at time t2. In this case, the switching means (not shown) of the speed controller 12 is switched by the establishment of the parallel condition, and the speed signal before parallel is switched to the speed command signal Na output from the active power controller 10. Therefore, a large speed deviation signal between the illustrated speed command signal Na and speed signal N is input to the speed controller 12.
In the speed controller 12, a large speed deviation signal is multiplied by a large proportional gain and is output to the frequency converter 4 via the current controller 13. As a result, in the frequency converter 4, the secondary current of the wound-rotor induction machine 1 is output so that the speed signal N approaches the speed command signal Na, so that the wound-rotor induction machine 1 operates as an electric motor (pumping direction), The active power P suddenly changes as shown. In addition, from time t1 in the figure to time t
The reason why the active power P1 of 3 is slightly negative is
This is because the frequency converter 4 is supplied with power from the grid 8 even before the parallel condition is satisfied.

In hydroelectric power generation, since the rotational time constant of the wound induction machine 1 and the pump turbine 2 combined is large, the speed controller 1
The proportional gain of 2 is very high and is set to 10 or more, for example. Therefore, the sudden change in the output current of the frequency converter 4 is large and cannot be ignored.

Therefore, an object of the present invention is to provide a power control device for a wire wound induction machine, which prevents a sudden change in active power by correcting a speed command when in parallel.

[0013]

SUMMARY OF THE INVENTION The present invention is a wire-wound type induction system in which a primary side is connected to a system via a parallel circuit breaker and a secondary side is directly connected to a pump turbine whose flow rate is controlled by a guide vane. Machine, a frequency converter that converts the system frequency into a variable frequency and outputs it to the secondary winding of this winding induction machine, the output of the active power command setter and the output of the active power detector of the system. The active power controller that adjusts the opening of the guide vanes and outputs the speed target signal, the speed detector that detects the speed signal of the wire wound induction machine, and the speed control that speed controls the wire wound induction machine in parallel. Controller, a current controller that controls the output current of the frequency converter from the current command of this speed controller and the output current of the frequency converter, and a signal based on the deviation between the speed target signal and the speed signal as a bias signal before paralleling. While outputting A speed command including bias signal output means for outputting a signal based on the deviation as zero after a row with a predetermined time constant, and means for adding the output of the bias signal output means and the speed target signal to output as a speed command signal. A creation unit and a calculation unit for calculating the deviation between the speed command signal output from the speed command creation unit and the speed target signal and outputting the deviation signal to the speed controller are provided. ..

[0014]

With the above structure, the speed command generating section outputs a speed command signal substantially similar to the speed signal to the deviation calculating means before the parallel connection. The deviation calculating means calculates the deviation between the speed command signal and the speed signal, and outputs a deviation signal close to zero to the speed controller. After the parallel connection, the speed command signal from the speed command generator approaches the speed target signal with a predetermined time constant, and this signal is output to the deviation calculating means. The deviation calculating means calculates the deviation between the signal and the speed signal, and after a predetermined time, the speed deviation signal between the speed command signal and the speed signal is input to the speed controller. Therefore, the active power of the system does not change suddenly when the wire wound induction machine is connected in parallel to the system.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram of a power control device for a wire wound induction machine showing an embodiment of the present invention. The difference from FIG. 4 is that the speed command creating unit 15 is additionally provided. The speed command generator 15 includes the speed target signal Nb output from the active power controller 10, the parallel condition, and the speed signal N of the speed detector 6.
Is input to output the speed command signal Na to the adder / subtractor 14.

In this embodiment, the adder / subtractor 14 outputs the speed target signal Nb output from the active power controller 10 in the speed command generator 15, the pre-parallel condition and the speed signal N output from the speed detector 6. The speed command signal Na is corrected and output so that the speed deviation signal becomes substantially zero, and after parallel connection, the speed command signal Na is gradually output so as to substantially match the speed target signal Nb.

The speed command generator 15 is specifically shown in FIG.
As shown in FIG. 5, the integrator 16, the parallel condition a contact 17a, the parallel condition b contact 17b, the adders 18a, 18b and 18c, and the fixed value setting device 19 are included. Before the parallel connection, the parallel condition a contact 17a is not established, and the parallel condition b contact 17b is established. For this reason, the speed signal N and the speed target signal Nb are added by the adder 18a with the symbols shown, and the deviation signal is input to the integrator 16 via the parallel condition b contact point 17b. The integrator 16 is configured to always overwrite the output of the integrator 16 with the deviation signal, and the deviation signal is overwritten and output as the bias signal B to the adder 18c. At this time,
The bias signal B is expressed by the following equation (1).

[0019]

[Equation 1] B = N-Nb ... (1)

Further, in the adder 18c, a speed command signal Na, which is added by the symbols shown in the figure and is expressed by the following equation (2), is output from the speed command creating section 15.

[0021]

## EQU00002 ## Na = (N-Nb) + Nb = N ......... (2)

That is, as shown in the above equation (2) and FIG. 3, the speed command signal Na output from the speed command generator 15 and the speed signal N change substantially at the time t1. The speed command signal Na is output to the adder / subtractor 14 where it is added to the speed signal N, and the deviation signal thereof is substantially zero. When the parallel condition is satisfied at time t2 in this state, the parallel condition a contact 17a is closed and the parallel condition b contact 17b is opened. In this case, a circuit is formed in which the output of the integrator 16 is fed back to the input of the integrator 16, and the output of the integrator 16, that is, the bias signal B and the zero value of the fixed value setting device 19 are added by the symbols shown. The generated signal is integrator 1
6 is input. As a result, the output of the integrator 16 attenuates from the value of the bias signal B before paralleling to a value of zero by a predetermined first-order delay time constant. Eventually, when the bias signal B becomes zero at time t4, the speed target signal Nb and the speed command signal Na substantially match, and the speed signal N also matches. Then, the speed command signal Na is gradually increased from time t5. In response to this, the active power P increases and is output to the grid.

As described above, since the speed command signal Na input to the adder / subtractor 14 which outputs the speed deviation signal is almost equal to the speed signal N and the speed deviation signal becomes zero and follows immediately after the parallel operation, the sudden change in the parallel operation occurs. After that, the pump turbine 2 can be shifted to the parallel operation so that the pump turbine 2 smoothly operates in high efficiency. In addition, in the present embodiment, it is possible to prevent a sudden change in active power during the power generation operation and the pumping operation.

[0024]

As described above, according to the present invention, before the parallel operation, a bias signal is added to the speed target signal to make the speed deviation substantially zero and the follow-up is performed, while after the parallel operation, the bias signal is gradually reduced to zero. Therefore, the speed command signal does not change stepwise after the parallel connection. Therefore, the sudden change of the secondary current does not occur, and the sudden change of the active power can be prevented.

[Brief description of drawings]

FIG. 1 is a system diagram of a power control device for a wire wound induction machine showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a speed command creating unit in FIG.

FIG. 3 is an explanatory diagram showing an example of the operation of FIG.

FIG. 4 is a system diagram of a power control device for a wound-rotor induction machine showing a conventional example.

5 is an explanatory diagram corresponding to FIG. 3, showing an example of the operation of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 winding type induction machine 4 frequency converter 10 active power controller 12 speed controller 13 current controller 14 adder / subtractor 15 speed command preparation section 1a rotor 1b stator

Claims (1)

[Claims] 1. A winding type induction machine in which a primary side is connected to a system via a parallel breaker and a secondary side is directly connected to a pump turbine whose flow rate is controlled by a guide vane, and this winding type induction machine. The guide vanes are opened from the frequency converter that converts the power of the system to a variable frequency and outputs the current to the secondary winding of the device, and the output of the active power command setter and the active power detector of the system. An active power controller that adjusts the speed and outputs a speed target signal, a speed detector that detects the speed signal of the wire-wound induction machine, and a speed controller that speed-controls the wire-wound induction machine in parallel. , A current controller for controlling the output current of the frequency converter from the current command of the speed controller and the output current of the frequency converter, and a signal based on the deviation between the speed target signal and the speed signal before paralleling. As a bias signal While outputting in parallel, the bias signal output means for outputting a signal based on the deviation as zero with a predetermined time constant after parallel, and the output of the bias signal output means and the speed target signal are added and output as a speed command signal. And a deviation calculating means for calculating a deviation between the speed command signal output from the speed command creating section and the speed target signal, and outputting the deviation signal to the speed controller. A power control device for a wire-wound induction machine, comprising: