JPH09327198A - Controller for variable speed hydraulic power station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller for variable speed hydraulic power station permitting stable running by avoiding the natural vibration frequency range of the runners of the hydraulic turbine or reversible-pump turbines. SOLUTION: Resonance range of the runner of a reversible-pump turbine is stored in advance in a resonance range map 14, and a discriminator 13 outputs a speed target value Ns' by avoiding the resonance range when the speed target value Ns of the reversible-pump turbine enters the resonance range of the runner. A speed control section 6 controls the AC secondary excitation in such a manner that the speed of the reversible-pump turbine 1 coincides with the speed target value Ns' from the discriminator 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a variable speed hydroelectric power generation system which controls the speed of a generator or a generator motor by variable speed by AC secondary excitation control.

[0002]

2. Description of the Related Art Generally, a variable speed hydroelectric power generation system is a system in which a generator or a generator motor connected in parallel in a system is operated at a variable speed at a speed (rotation speed) with good operation efficiency. In this case, since it is necessary to match the output frequency of the generator or the generator motor with the system frequency, the control is performed by AC secondary excitation.

FIG. 6 is a schematic diagram of a control device of a variable speed pumped storage power generation system. A variable speed generator motor 2 is directly connected to the pump turbine 1. The function generator 4 generates a variable speed target value Ns based on the head H at the pumped storage power plant and the generator motor output command value P0.
The speed at a point where the operation efficiency of the variable speed generator motor 2 or the like is high is obtained as the speed target value Ns.

The rotational speed N of the variable speed generator-motor 2 is detected by the resolver 3, and the subtractor 5 calculates the speed deviation ΔN from the speed target value Ns from the function generator 4. This speed deviation ΔN is input to the secondary excitation device 8 via the speed controller 6 and the output limiter 7. The secondary excitation device 8 has a difference frequency between the system frequency and the frequency with respect to the rotation speed,
The AC exciting current is output to the variable speed generator motor 2. This alternating excitation current can be decomposed into a d-axis component and a q-axis component on the orthogonal axis, the active power of the generator motor 2 is controlled by the q-axis component, and the reactive power is controlled by the d-axis component.

Next, the subtractor 9 outputs the output deviation ΔP between the output command value P0 and the current output PE, and this output deviation ΔP
Is input to the guide vane servo 11 via the guide vane control circuit 10. This guide vane servo 11 is based on the output deviation ΔP, and the guide vane 12 of the pump turbine 1
Drive to the proper position. As a result, the pump turbine 1 outputs the output according to the position of the guide vane 12 to the variable speed generator-motor 2.

[0006]

However, when the runner of the pump turbine is operated at a variable speed, it receives an exciting force having various frequencies according to the variable speed.
When the exciting force frequency matches the natural vibration frequency of the runner, resonance occurs in the runner. When the runner resonates, the runner may be damaged.

It is known that there are a plurality of natural frequencies of the runner due to its complicated shape and vibration mode. When the operation width of variable speed operation is expanded, those natural frequencies are variable speed operation. It may fall into the width. Also,
In the conventional pump turbine, the output command value P is used to select the rotation speed.
The speed target value Ns is uniquely determined from 0 and the head H, and the operation may be performed at a rotational speed to which an exciting force corresponding to the natural frequency of the runner is applied. In that case,
There was no way to detect or avoid it.

An object of the present invention is to provide a control device for a variable speed hydroelectric power generation system, which avoids the natural vibration frequency range of a runner of a water turbine or a pump water turbine and enables stable operation.

[0009]

According to a first aspect of the present invention, the AC secondary excitation of the variable speed generator-motor is performed so that the speed of the pump turbine directly connected to the variable speed generator-motor matches the speed target value of the variable speed. A control device for a variable speed hydroelectric system configured to control, wherein a resonance range map pre-stores the resonance range of the runner of the pump turbine and the resonance when the target speed value of the pump turbine falls within the resonance range of the runner. It is provided with a discriminator that outputs a speed target value that avoids the range, and a speed controller for controlling the AC secondary excitation so that the speed of the pump turbine matches the speed target value from the discriminator. .

According to the first aspect of the present invention, the resonance range of the runner of the pump turbine is stored in advance in the resonance range map, and when the speed target value of the pump turbine falls within the resonance range of the runner, the discriminator determines the resonance range. The avoided speed target value is output. Then, the speed control unit controls the AC secondary excitation so that the speed of the pump turbine matches the speed target value from the discriminator.

According to a second aspect of the present invention, the variable speed AC variable excitation is controlled so that the speed of the water turbine directly connected to the variable speed generator matches the speed target value of the variable speed generator. A control device for a hydraulic power generation system, which outputs a resonance range map in which the resonance range of the turbine runner is stored in advance and a speed target value that avoids the resonance range when the turbine speed target value falls within the runner resonance range. And a speed controller for controlling the AC secondary excitation so that the speed of the water turbine matches the speed target value from the classifier.

In the invention of claim 2, the resonance range of the runner of the water turbine is stored in advance in the resonance range map, and when the speed target value of the water turbine falls within the resonance range of the runner, the discriminator avoids the resonance range. Output the target speed value. Then, the speed controller controls the AC secondary excitation so that the speed of the water turbine matches the speed target value from the discriminator.

According to the third aspect of the present invention, the AC secondary excitation of the variable speed generator / motor is controlled so that the speed of the pump turbine directly connected to the variable speed generator / motor matches the speed target value of the variable speed generator. A control device for a variable speed hydroelectric power generation system, comprising a stress sensor for detecting stress generated in a runner of a pump turbine, an FFT analyzer for frequency-analyzing the stress value detected by the stress sensor, and a frequency-analyzed by the FFT analyzer. If the fluctuating stress in the frequency component exceeds the reference value, a discriminator that outputs a speed target value that is less than the reference value, and an alternating current input so that the speed of the pump turbine matches the speed target value from the discriminator And a speed controller for controlling secondary excitation.

According to the third aspect of the present invention, the stress generated in the runner of the pump turbine is detected by the stress sensor, and the stress value detected by the stress sensor is frequency-analyzed by the FFT analyzer.
When the fluctuating stress in each frequency component frequency-analyzed by the FT analyzer exceeds the reference value, the discriminator outputs a speed target value that is less than the reference value. Then, the speed controller controls the AC secondary excitation so that the speed of the pump turbine matches the speed target value from the discriminator.

According to a fourth aspect of the present invention, the variable speed AC is controlled so that the speed of the water turbine directly connected to the variable speed generator matches the speed target value of the variable speed generator. A control device for a hydraulic power generation system, wherein a stress sensor that detects stress generated in a runner of a water turbine, an FFT analyzer that frequency-analyzes the stress value detected by the stress sensor, and each frequency component frequency-analyzed by the FFT analyzer If the fluctuating stress at exceeds the reference value, a discriminator that outputs a speed target value that is less than the reference value and AC secondary excitation so that the speed of the water turbine matches the speed target value from the discriminator And a speed controller for controlling.

According to the invention of claim 4, the stress generated in the runner of the water turbine is detected by the stress sensor, the stress value detected by the stress sensor is frequency-analyzed by the FFT analyzer, and each frequency component frequency-analyzed by the FFT analyzer. If the fluctuating stress at exceeds the reference value, the discriminator outputs a speed target value that is less than the reference value. Then, the AC secondary excitation is controlled so that the speed of the water turbine matches the speed target value from the discriminator.

[0017]

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram showing a first embodiment of the present invention, which is applied to a variable speed pumped storage power generation system.

In FIG. 1, a pump turbine 1 is used as a hydraulic machine and a generator-motor 2 is used as an electric machine in the variable speed pumped storage power generator. That is, during the power generation operation, the pump turbine 1 operates as a turbine and the generator motor 2
Is operated as a generator. On the other hand, during the pumping operation, the pump turbine 1 is operated as a pump and the generator motor 2 is operated as an electric motor. Variable speed operation is performed in both the power generation operation and the pumping operation.

The function generator 4 generates a variable speed target value Ns based on the effective head H at the pumped storage power plant and the generator motor output command value P0. The pump turbine 1 and the variable speed generator motor 2 and the like. The speed at the point where the driving efficiency is good is obtained as the speed target value Ns.

The target speed value Ns output from the function generator 4 is compared with the resonance range of the runner of the pump turbine 1 stored in advance in the resonance range map 14 in the discriminator 13. Then, when the speed target value Ns is within the resonance range of the runner, the discriminator 13 corrects the speed target value Ns so as to be out of the resonance range, and the corrected speed target value Ns ′ is applied to the subtractor 5. Output. On the other hand, when the speed command value Ns is not within the resonance range of the runner of the pump turbine 1, the speed command value Ns
Is output as is.

As shown in FIG. 2, the resonance range map 14 is a map in which the range in which the runner's fluctuation stress σa is larger than that during normal operation is preliminarily mapped as the resonance ranges A1 to A3. FIG. 2 shows that there are three resonance ranges A1 to A3.

The discriminator 13 determines whether or not the speed target value Ns is within the resonance range A1 to A3. Then, for example, when the speed target value Ns is within the resonance range A1, the discriminator 13 determines that the resonance range A1 is present when the speed target value Ns is larger than the median value of the resonance range A1.
Corrected to a speed target value outside the resonance range of higher speed, and conversely,
When the speed target value Ns is smaller than the median value of the resonance range A1, the speed target value Ns is corrected to a speed target value outside the resonance range that is lower than the resonance range A1. Then, the corrected speed target value Ns'
Is output to the subtractor 5.

The rotational speed N of the variable speed generator / motor 2 detected by the resolver 3 is input to the subtractor 5, and the subtractor 5 deviates the speed deviation from the speed target value Ns (Ns') from the function generator 4. ΔN is calculated. This speed deviation ΔN is input to the secondary excitation device 8 via the speed controller 6 and the output limiter 7. The secondary excitation device 8 outputs an alternating excitation current to the variable speed generator-motor 2 at a frequency that is the difference between the system frequency and the frequency with respect to the rotation speed. This alternating excitation current can be decomposed into a d-axis component and a q-axis component on the orthogonal axis, the active power of the generator motor 2 is controlled by the q-axis component, and the reactive power is controlled by the d-axis component.

Next, the subtractor 9 outputs the output deviation ΔP between the output command value P0 and the current output PE, and this output deviation ΔP
Is input to the guide vane servo 11 via the guide vane control circuit 10. This guide vane servo 11 is based on the output deviation ΔP, and the guide vane 12 of the pump turbine 1
Drive to the proper position. As a result, the pump turbine 1 outputs the output according to the position of the guide vane 12 to the variable speed generator-motor 2.

As described above, by these controls, the variable speed pumped storage power generator can avoid the rotation speed corresponding to the natural frequency of the runner of the pump turbine 1 and perform stable operation.

The above description relates to the power generation operation of the variable speed pumped storage power generator, but similarly during the pumping operation, the same control can be performed by providing the runner resonance range map during the pumping operation. it can.

Next, FIG. 3 is a configuration diagram showing a second embodiment of the present invention. The second embodiment is applied to a variable speed power generator in place of the variable speed pumped storage power generator in the first embodiment shown in FIG. In the variable speed power generator, a water turbine 15 is used as a hydraulic machine, and a generator 16 is used as an electric machine. Other configurations are
Since it is the same as the first embodiment shown in FIG. 1, the same elements are denoted by the same reference numerals, and the description thereof will be omitted. This second
According to the embodiment, the operation is performed while avoiding the rotation speed corresponding to the natural frequency of the runner in the water turbine 15.

Next, FIG. 4 is a block diagram showing a third embodiment of the present invention. The third embodiment is different from the first embodiment shown in FIG. 1 in that instead of the resonance range map 14, a stress sensor 17 for detecting the stress generated in the runner is provided. The detected stress value is FF
When the fluctuating stress value σa in each frequency component exceeds the reference value by frequency analysis with the T analyzer 18, the judging device 1
The target velocity value Ns is corrected at 3 and sent to the subtractor 5. Since other configurations are the same as those of the first embodiment shown in 1, the same elements are denoted by the same reference numerals and the description thereof will be omitted.

Next, FIG. 5 is a block diagram showing a fourth embodiment of the present invention. The fourth embodiment is applied to a variable speed power generation device in place of the variable speed pumped storage power generation device as compared with the second embodiment shown in FIG. In the variable speed power generator, a water turbine 15 is used as a hydraulic machine, and a generator 16 is used as an electric machine. Since other configurations are the same as those of the third embodiment shown in FIG. 4, the same elements are denoted by the same reference numerals and the description thereof will be omitted. According to the fourth embodiment, operation is performed while avoiding the rotation speed corresponding to the natural frequency of the runner in the water turbine 15.

[0030]

As described above, according to the present invention, even when the rotational speed corresponding to the natural frequency of the runner in the water turbine or the pump water turbine is included in the variable speed operation range, harmful fluctuations to the runner are caused. Stable operation can be performed without generating stress.

That is, since the exciting force corresponding to the natural frequency of the runner in the turbine or the pump turbine is not applied, resonance of the runner does not occur. Therefore, stable operation can be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a runner resonance range stored in a resonance range map of the present invention.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of the present invention.

FIG. 5 is a configuration diagram showing a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional example.

[Explanation of symbols]

 1 Pump turbine 2 Variable speed generator motor 3 Resolver 4 Function generator 5 Subtractor 6 Speed controller 7 Output limiter 8 Secondary exciter 9 Subtractor 10 Guide vane control circuit 11 Guide vane servo 12 Guide vane 13 Discriminator 14 Resonance range Map 15 Turbine 16 Variable speed generator 17 Stress sensor 18 FFT analyzer

Claims (4)

[Claims] 1. A variable speed hydroelectric system in which AC secondary excitation of the variable speed generator motor is controlled so that the speed of a pump turbine directly connected to the variable speed generator motor matches a speed target value of the variable speed generator motor. In the control device, the resonance range map in which the resonance range of the runner of the pump turbine is stored in advance, and when the speed target value of the pump turbine falls within the resonance range of the runner, the speed target value avoiding the resonance range is output. And a speed controller for controlling the AC secondary excitation so that the speed of the pump turbine matches the speed target value from the classifier. The control unit of the system. 2. A variable speed hydroelectric system in which AC secondary excitation of the variable speed generator is controlled so that the speed of a water turbine directly connected to the variable speed generator matches a speed target value of the variable speed generator. In the control device, a resonance range map in which the resonance range of the runner of the water turbine is stored in advance, and a discriminator that outputs a speed target value avoiding the resonance range when the speed target value of the water turbine falls within the resonance range of the runner. And a speed controller for controlling the AC secondary excitation so that the speed of the water turbine matches the speed target value from the discriminator. . 3. A variable speed hydroelectric system in which AC secondary excitation of the variable speed generator motor is controlled so that the speed of a pump turbine directly connected to the variable speed generator motor matches a speed target value of the variable speed generator motor. In the control device of, a stress sensor for detecting the stress generated in the runner of the pump turbine,
F for frequency-analyzing the stress value detected by the stress sensor
An FT analyzer, a discriminator that outputs a speed target value that is less than the reference value when the fluctuating stress in each frequency component frequency-analyzed by the FFT analyzer exceeds the reference value, and the speed of the pump turbine A controller for a variable-speed hydroelectric power generation system, comprising: a speed controller for controlling the AC secondary excitation so as to match the speed target value from the discriminator. 4. A variable speed hydraulic power generation system for controlling AC secondary excitation of the variable speed generator so that the speed of a water turbine directly connected to the variable speed generator matches a speed target value of the variable speed generator. In the control device, a stress sensor that detects stress generated in the runner of the water turbine, an FFT analyzer that frequency-analyzes the stress value detected by the stress sensor, and a variable stress in each frequency component frequency-analyzed by the FFT analyzer. If the value exceeds the reference value, a discriminator that outputs a speed target value that is less than the reference value, and the AC secondary excitation so that the speed of the water turbine matches the speed target value from the discriminator. A control device for a variable-speed hydroelectric power generation system, comprising: a speed controller for controlling.