JPH11113296A - Controller for generator motor and power generation system employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller for a generator motor for suppressing an overvoltage occurring immediately after separating a faulty phase from a system. SOLUTION: A generator motor 18 is connected with a power system 24 and controlled to produce an output voltage corresponding to a voltage command value VO using a voltage regulator 15, an excitation controller 16 and a power converter 17. A voltage command value modifying unit 12 is interposed between a voltage command generator 11 and a subtractor 14 while being connected with a fault detector 13. When the fault detector 13 detects a fault on a power system 24, the voltage command value modifying unit 12 lowers an inputted voltage command value VO to a specified level V before being outputted.

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 generator motor for AC-exciting the secondary side of a generator motor.
The present invention relates to a control device for a generator motor used for suppressing overvoltage of a system in a variable speed power generation system, and a power generation system using the same.

[0002]

2. Description of the Related Art In a power generation system, for example, a variable speed power generation system, a generator motor is operated at a variable speed so as to keep the frequency of a system constant with a change in power demand, and the output is adjusted as in a variable speed pumped storage power plant. It has the function to do. If an accident, such as a ground fault, occurs anywhere in the power system, the phase in which the accident occurred is separated by a circuit breaker, and the fault of the accident is removed from the power system. Further, the variable speed power generation system is controlled so as to output a predetermined voltage even when a voltage drop occurs at the time of a system failure.

[0003]

The above-mentioned variable speed power generation system is controlled so as to output a predetermined voltage even if the voltage of the power system drops during an accident such as a ground fault accident. When removing the accident phase, the voltage rises due to the surplus reactive power of the power system. For example, in a case where a ground fault occurs on the AC side in an ultra-high voltage DC transmission system, there is an example in which the voltage is increased by the action of a loading capacitor installed in parallel with the transmission line. In such a case, the control is performed such that the voltage rise is detected and the voltage is reduced based on the detected voltage rise. Therefore, there is a problem that a control delay is added and an overvoltage that rises momentarily cannot be suppressed.

[0004] It is an object of the present invention to provide a control device for a generator motor that performs control so as to suppress an overvoltage that occurs immediately after an accident occurs in a system and an accident phase is disconnected from the system.

It is another object of the present invention to provide a power generation system capable of suppressing an overvoltage that occurs immediately after an accident occurs in a system and an accident phase is separated from the system.

[0006]

In order to achieve the above-mentioned object, the present invention provides a motor generator having a primary side connected to a power system, based on a detected value of an output voltage and an output voltage command value of the generator motor. Generator motor voltage control means for controlling the output voltage; AC current output means for outputting a variable frequency AC current according to the output of the generator motor voltage control means; and a secondary side of the generator motor by the AC current output means. A control device provided with exciting means for exciting the AC power, wherein an accident detecting means for detecting occurrence of an accident in the power system, and a voltage command value changing means for reducing the output voltage command value in response to the accident detection by the accident detecting means. The control device of the generator motor provided with: According to this configuration, when an accident occurs in the power system, the occurrence is electrically detected by the accident detecting means, and the voltage command value changing means lowers the output voltage command value in conjunction with the detection. As a result, when the fault phase is removed by the circuit breaker following the fault, it is possible to suppress the occurrence of overvoltage in the power system.

To achieve the above and other objects, the present invention relates to a pumping power generation system or a flywheel power generation system, comprising: a generator motor having a primary side connected to a power system; a detection value of an output voltage of the generator motor; Generator motor voltage control means for controlling the output voltage of the generator motor based on an output voltage command value; AC current output means for outputting a variable frequency AC current according to the output of the generator motor voltage control means; Exciting means for AC-exciting the secondary side of the generator motor by current output means, accident detecting means for detecting occurrence of an accident in the power system, and lowering the output voltage command value in response to the accident detecting means detecting the accident. The power generation system is provided with a control device including a voltage command value changing means for causing the power generation system to be connected to the power system. According to this configuration, in any of the power generation systems, when an accident occurs in the power system and the voltage of the power system rises, the control device starts immediately and the output voltage command value is changed. Works to lower. Therefore, occurrence of overvoltage in the power system can be suppressed.

[0008]

Embodiments of the present invention will be described below. FIG. 1 shows a first embodiment of a control device for a generator motor according to the present invention. FIG. 1 shows a case where a control device for a generator motor is applied to a variable speed power generation system. The variable speed power generation system 10 includes a source voltage command generator 11 for generating a voltage command value V0, a voltage command value changer 12 for outputting a voltage command value V based on the voltage command value V0, and a The connected fault detector 13, a subtractor 14 for subtracting the voltage command value V and the detected voltage value VF, a voltage regulator 15 connected to the subtractor 14, and an excitation controller 16 connected to the voltage regulator 15. A power converter 17 connected to the excitation controller 16, a generator motor (for example, a synchronous motor) 18 having a secondary side connected to the power converter 17, an excitation transformer 19 connected to the power converter 17, Generator motor 1
Current transformer 20 for measuring the current flowing through 8, generator motor 18
And a transformer 21 connected to the exciting transformer 19, and a voltage detector 22 for generating a voltage detection value VF based on the output of the transformer 21. In the above configuration, the subtractor 14 and the voltage regulator 15 form a voltage control unit,
The excitation control device 16 forms the excitation means, and the power converter 17
Form AC current output means. In contrast to the variable speed power generation system 10 having the above-described configuration, a main transformer 23 is connected to a connection point between the generator motor 18 and the exciting transformer 19 of the variable speed power generation system 10, and the main transformer 23 is connected to the power system. 2
4 are connected.

The operation of the control system for controlling the output voltage of the generator motor 18 in the above configuration will be described. The output voltage of the generator motor 18 is detected by the voltage detector 22 as a voltage detection value VF. This voltage detection value VF is compared with the voltage command value V output from the voltage command value changer 12 of the variable speed power generation system 10 by the subtractor 14, and the deviation is input to the voltage regulator 15, and furthermore, the excitation controller The power converter 17 is controlled via 16. The detection point of the output voltage of the variable speed power generation system 10 may be the output terminal of the generator motor 18 or the primary side (power system side) of the main transformer 23. The power converter 17 performs AC excitation on the secondary side of the generator motor 18, whereby the output voltage of the generator motor 18 is changed to the output voltage command value V and the voltage detection value VF of the variable speed power generation system 10.
It changes according to the deviation of. The excitation control device 16 detects the secondary current of the generator motor 18 with the current transformer 20, and the detected value is fed back to the excitation control device 16.

In the configuration shown in FIG. 1, a voltage command value V0 of the variable speed power generation system 10 determined by the voltage set value of the power system 24 is input to the voltage command value changer 12, and the output thereof is applied to the voltage of the variable speed power generation system 10. It is used as the command value V. When receiving the signal from accident detector 13, voltage command value changer 12 lowers voltage command value V0 to voltage command value V. This accident refers to a ground fault accident or the like. The voltage command value V is set to be equal to or less than the voltage detection value or a value determined by the voltage set value of the power system 24. Thus, by providing the voltage command value changer 12 and the accident detector 13 and transmitting the signal of the accident detector 13 to the voltage command value changer 12, the variable speed power generation system 10 causes an accident in the power system 24. Then, the output voltage command value V0 of the variable speed power generation system 10 can be changed to the voltage command value V. As a result, when returning from an accident to a normal state, the output voltage can be reduced, and an overvoltage generated in the power system immediately after the recovery can be suppressed.

FIG. 2 shows the detailed configuration of the voltage command value changer 12. The voltage command value changer 12 is a pulse width extender 1 that operates based on an accident detection signal output from the accident detector 13.
2a, a multiplier 12b that multiplies the output value of the pulse width expander 12a by the voltage command value V0, a subtractor 12c that outputs a deviation between the output value of the multiplier 12b and the voltage command value V0, and an output of the subtractor 12c Is provided with a ramp circuit 12d for outputting a predetermined signal based on the above.

In the configuration shown in FIG. 2, the accident detector 13
When an accident is detected, a signal "1" is generated, and when an accident is not detected, "0" is generated, and this signal is transmitted to the pulse width expander 12a. The pulse width expander 12a has a function of, when a signal "1" is input, holding the state for a certain period of time. When the output signal “1” of the pulse width expander 12a is input to the multiplier 12b, the multiplier 12b
Is a constant α (where 0 ≦ α)
<1) The value (α · V0) multiplied by (1) is output. On the other hand, when the output of the pulse width expander 12a is "0", the multiplier 12b
Outputs "0" to the subtractor 12c.

FIG. 3 is a waveform diagram showing the operation of each section of the variable speed power generation system 10 having the configuration shown in FIG. An example of means for realizing a time function as shown in the figure as a change in the output voltage command value V0 of the variable speed power generation system when an accident occurs in the system will be described with reference to the figure. When the fault signal of the fault detector 13 is "0", that is, when no fault is detected, the output of the multiplier 12b is "0". Therefore, the output terminal of the ramp circuit 12d is connected to the subtractor 12c.
Is output as it is. When an accident occurs and the output of the accident detector 13 becomes "1", that is, an accident signal after the accident due to detection delay, the pulse width expander 12a detects the rise of the signal and keeps the signal rising for a certain period of time. . The multiplier 12b inputs a value obtained by multiplying the input signal V0 by α to the subtractor 12c while the output of the pulse width expander 12a is "1". As a result, the ramp circuit 12d outputs a voltage signal in which the signal V0 is stepwise reduced to [α · V0].

The holding time of the pulse width expander 12a is represented by time T
When it is set to 1, as shown in FIG. 3, the output voltage command value V0 of the variable speed power generation system 10 is [α · V0
] Is reduced. At this time, it is necessary to select the value of the time T1 such that the output voltage command value V0 decreases when the fault phase is released. Alternatively, the holding time may be set such that the time T2 is determined from the opening of the accident phase. In FIG. 3, the ramp circuit 12d instantaneously becomes equal to the input value when the input value decreases, and gradually increases when the input value increases so as to become equal to the input value at a predetermined slope. The method of changing the voltage command value V0 can be selected by changing the ramp circuit 12d in FIG. When the input value decreases, the input value may decrease instantaneously as shown in the figure, or may have a slope. Further, when increasing, it may be increased at a fixed slope, or may be made equal to the input value V0 after a certain time. Alternatively, a first-order lag element may be used instead of the ramp circuit.

According to the present embodiment, the variable speed power generation system 10 can reduce the output voltage command value V0 of the variable speed power generation system 10 between the occurrence of an accident and the release of the accident phase. As described above, the output voltage command value V0 of the variable speed power generation system 10 is reduced until a predetermined time has elapsed after the recovery from the accident, and therefore, the output voltage of the variable speed power generation system 10 should be kept low after the normal recovery. Can be. With this effect, it is possible to prevent the voltage of the system from becoming excessive after the normal recovery including the time of an accident. After the normal recovery, after the system disturbance has attenuated, the output voltage of the variable speed power generation system 10 becomes a value corresponding to a predetermined voltage of the system,
That is, it returns to the value before the accident.

Next, another embodiment of the present invention will be described. In the following, the same reference numerals are used for constituent members having the same or the same function throughout the drawings, and a detailed description thereof will be omitted. FIG. 4 shows a second embodiment of the control device for the generator motor according to the present invention. In FIG. 4, the same reference numerals are used for the same components as those in FIG. 1, and thus, duplicate description will be omitted below. The configuration of FIG. 4 differs from that of FIG. 1 in the configuration of the voltage command value changer, and the output (voltage detection value VF) of the voltage detector 22 is one of the input signals. That is, in the present embodiment, a configuration is adopted in which the detected value VF of the system voltage is input to the command value changer 25 to change the decrease amount of the voltage command value. The command value changer 25 outputs a multiplier 1 based on the detected voltage VF.
A gain α of 6 is set. For other configurations,
It is the same as FIG.

FIG. 5 shows a detailed configuration of the command value changer 25. This configuration is different from FIG. 2 in that a gain setting device 12e is connected to the multiplier 12b, and the gain setting device 12e
Is applied with the voltage detection value VF of the voltage detector 22. Other configurations are the same as those in FIG. With the configuration of FIG. 5, the voltage command value V0 can be changed according to the state of the system fault, the effect of suppressing the system overvoltage at the time of recovery from the fault becomes greater, and the output voltage of the variable speed power generation system You can return to the previous state.

FIG. 6 shows a third embodiment of the control device for a generator motor according to the present invention. In FIG. 6, the same reference numerals are used for the same components as those in FIGS. 1 and 5,
In the following, duplicate description will be omitted. The configuration of FIG. 6 is different from that of FIG. 1 in that the second configuration for detecting the voltage detection value VFa
Is connected to the command value changer 25 shown in FIG. 5, and the voltage detector 26 and the power system 24 (the main transformer 23
(Primary side) is connected to the transformer 27. As described above, the voltage detection means 26 is installed on the primary side of the main transformer 23 and the detected system voltage VFa is input to the command value changer 25, so that the system voltage is directly transmitted without passing through the main transformer 23. This makes it possible to detect the system voltage without being affected by an error due to leakage of the main transformer 23, and to more accurately detect an accident state of the system.

FIG. 7 shows a fourth embodiment of the control device for a generator motor according to the present invention. In FIG. 7, the same reference numerals are used for the same components as those in FIG. 1, and thus the duplicate description will be omitted below. The configuration of FIG. 7 differs from that of FIG. 1 in that an accident detector 28 that outputs an accident detection signal based on a system breaker operation signal 29 is provided instead of the accident detector 13 of FIG. According to this configuration, the operation signal 29 of the circuit breaker for opening the accident phase is used as the input signal of the accident detector 28 of the variable speed power generation system 10. Transmits an accident signal to the voltage command value changer 12. When an accident occurs in the power system, the operation signal 29 of the circuit breaker is transmitted to the voltage command value change unit 12 as “1” when the accident occurs and “0” when it is normal, thereby outputting the output voltage of the variable speed power generation system 10. The command value V0 can be changed. As a result, a system fault can be detected without installing a new fault detector, and the voltage command value V0 of the variable speed power generation system 10 can be changed.

FIG. 8 shows a fifth embodiment of the control device for a generator motor according to the present invention. In FIG. 8, the same reference numerals are used for the same components as those in FIG. 1, and thus redundant description will be omitted below. 8 differs from FIG. 1 in that an accident detector 30 having an output voltage of the transformer 21 as an input signal is provided, and the accident detection signal is applied to the voltage command value changer 12. . According to this configuration, the accident detector 30 calculates the fundamental-wave negative-phase voltage Vn with respect to the voltage on the primary side of the generator motor 18 according to Equations 1 to 3 based on Fourier transform. The angular frequency of the system is ω
Then, the reverse phase voltage Vn is represented by Expression 3. The accident here indicates a one-line ground fault or a two-line ground fault.

(Equation 1)

(Equation 2)

(Equation 3)

FIG. 9 shows a detailed configuration of the accident detector 30 shown in FIG. The accident detector 30 has a fundamental-wave negative-phase component calculator 30a to which the output voltage of the transformer 21 is input, and a fundamental-wave negative-phase voltage Vn and a predetermined value Vn0 by the fundamental-wave negative-phase component calculator 30a.
Is provided with a comparator 30b for comparing. In FIG. 9, the negative-sequence voltage Vn obtained by the equation (3)
0b is compared with a predetermined value Vn0. The comparator 30b outputs a signal "0" when the predetermined value Vn0 is larger than the detection value Vn, and outputs a signal "1" as an accident detection signal to the voltage command value changer 12 when Vn0 is smaller than Vn. According to this configuration, since the negative-phase component is used for detecting the output voltage of the generator motor 18, an accident in which the output terminal voltage of the variable speed power generation system 10 becomes asymmetric can be detected.

FIG. 10 shows a sixth embodiment of the control device for a generator motor according to the present invention. In FIG. 10, FIG.
Since the same reference numerals are used for the same elements as those described above, redundant description will be omitted below. The configuration of FIG.
The difference is that the voltage detector 31 that outputs the positive-phase component voltage VP based on the output of the transformer 21 is different from the transformer 21 and the subtractor 1.
4 and a fault detector 32 for generating a fault detection signal based on the positive-phase voltage VP and applying the generated fault detection signal to the voltage command value changer 12. The accident here refers to all ground faults. The feedback system of the variable-speed power generation system 10 is formed by detecting the positive-phase component Vp of the fundamental wave by the voltage detector 31 as a system voltage and applying the same to the subtractor 14. The detected positive-phase voltage Vp is input to the fault detector 32, and the voltage command value V0 is changed based on the positive-phase voltage Vp. The positive-phase voltage Vp is obtained by converting sin (−ωt) of Expression 1 into sin based on the Fourier transform.
(Ωt), cos (−ωt) in Equation 2 is replaced by cos (ωt)
A1 and b1 are obtained, and based on these, the following equation is obtained.

(Equation 4)

FIG. 11 shows a detailed configuration of the accident detector 32 of FIG. The accident detector 32 includes a comparator 32a for comparing the positive-phase component voltage VP with a predetermined value Vp0. The positive-phase voltage Vp obtained by the equation (4) is compared with a predetermined value Vp0 by the comparator 32a. The comparator 32a outputs a signal "0" when the positive-phase voltage Vp is higher than a predetermined value Vp0, and outputs a signal "1" as an accident detection signal to the voltage command value changer 12 when the positive-phase voltage Vp is lower than the predetermined value Vp0. Output. According to this configuration, since the positive-phase component (positive-phase voltage Vp) of the fundamental wave is used to detect the output voltage of the generator motor 18, even when a negative-phase component exists in the system, the system voltage can be accurately reduced. Can be detected.

In each of the above embodiments, the variable speed power generation system 10 having only one generator motor has been described as an example. However, the present invention is not limited to this. The present invention is also applicable to a flywheel power generation system having a flywheel in a generator motor. Although the ground fault has been described as an example of the fault, the present invention can be applied to other faults such as a short circuit between lines.

[0025]

As is clear from the above, according to the control device of the present invention, the output voltage command value is lowered when an accident occurs in the power system. Can be reduced, and an overvoltage generated in the power system immediately after the return can be suppressed. Further, since the output voltage of the variable speed power generation system is reduced in accordance with the decrease in the system voltage, overvoltage can be suppressed even for accidents other than the system accident.

Further, according to the power generation system of the present invention, by applying the present invention to a pumped storage power generation system or a flywheel power generation system, a system for suppressing overvoltage in the event of a system failure while normally stabilizing the voltage and frequency of the system. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a control device for a generator motor according to the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a voltage command value changer of FIG.

FIG. 3 is a waveform chart showing an operation of each unit of the variable speed power generation system having the configuration of FIG.

FIG. 4 is a block diagram showing a second embodiment of a control device for a generator motor according to the present invention.

FIG. 5 is a block diagram showing a detailed configuration of a command value changer of FIG. 4;

FIG. 6 is a block diagram showing a third embodiment of a control device for a generator motor according to the present invention.

FIG. 7 is a block diagram showing a fourth embodiment of the control device for the generator motor according to the present invention.

FIG. 8 is a block diagram showing a fifth embodiment of a control device for a generator motor according to the present invention.

9 is a block diagram showing a detailed configuration of the accident detector shown in FIG.

FIG. 10 is a block diagram showing a sixth embodiment of the control device for the generator motor according to the present invention.

11 is a block diagram showing a detailed configuration of the accident detector shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 variable speed power generation system 11 voltage command generator 12, 25 voltage command value changer 12a pulse width expander 12b multiplier 12c subtractor 12d ramp circuit 12e gain setting device 13, 28, 30, 32 accident detector 14 subtractor 15 Voltage regulator 16 Excitation controller 17 Power converter 18 Generator motor 19 Exciting transformer 21 Transformer 22, 31 Voltage detector 23 Main transformer 24 Power system 30a Fundamental wave anti-phase component calculator 32a, 30b Comparator V0, V Voltage command value Vn Negative phase voltage detection value Vp Positive phase voltage detection value

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Joe Kubota 7-2-1, Omika-cho, Hitachi City, Ibaraki Pref. Hitachi, Ltd. Power and Electricity Development Division (72) Inventor Mitsuyuki Omika-cho, Hitachi City, Ibaraki Prefecture 7-2-1, Hitachi, Ltd. Power and Electricity Development Division (72) Inventor Mikisuke Higuchi 3-1-1, Saimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Masatoshi Endo 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref.Hitachi, Ltd.Hitachi Plant (72) Inventor Kiyoshi Minoguchi 3-2-2 Nakanoshima, Kita-ku, Osaka-shi, Osaka Kansai Electric Power Co., Inc. (72 ) Inventor Toru Nishio 3-2-2 Nakanoshima, Kita-ku, Osaka-shi, Osaka Inside Kansai Electric Power Company

Claims (11)

[Claims] 1. A generator motor voltage control means for controlling an output voltage of the generator motor based on a detected value and an output voltage command value of the generator motor whose primary side is connected to a power system, and the generator motor voltage control. An AC current output means for outputting an AC current having a variable frequency corresponding to an output of the means, and a generator motor control device comprising: an exciting means for exciting the secondary side of the generator motor by the AC current output means. A control device for a generator motor, comprising: an accident detecting means for detecting occurrence of an accident in a power system; and a voltage command value changing means for reducing the output voltage command value in response to the accident detection by the accident detecting means. 2. The control device for a generator motor according to claim 1, wherein said accident detection means generates an accident detection signal based on an operation signal of a system breaker installed on said power system side. 3. An output voltage detecting means for detecting an output voltage on a primary side of the generator motor is provided in place of the fault detecting means, and a decrease in the detected voltage is used as fault occurrence information in the power system. The control device for a generator motor according to claim 1. 4. The power generation system according to claim 1, wherein the accident detection means detects a positive-phase component of the voltage of the power system, and detects occurrence of an accident in the power system based on the detected value. Motor control device. 5. The fault detecting device according to claim 1, wherein the fault detecting means detects a negative-phase component of an output voltage of the generator motor, and detects occurrence of a fault in the power system based on the detected value. Control device for generator motor. 6. The control device for a generator motor according to claim 1, wherein said voltage command value changing means sets said output voltage command value to a voltage detection value or less in response to said accident detection. 7. The voltage command value changing unit, after the power system returns to a normal state, changes the reduced output voltage command value to a value determined by a voltage set value of the power system. The control device for a generator motor according to claim 1. 8. The voltage command value changing means determines the output voltage command value, which has been lowered, by a voltage set value of the power system after a lapse of a predetermined time after the power system returns to a normal state. 2. The control device according to claim 1, wherein the control value is changed to a value. 9. A pulse width extender for holding an output signal for a fixed time in synchronization with generation of an accident detection signal from said accident detection means, said voltage command value changing means; A multiplier that multiplies the voltage command value, a subtractor that subtracts the output of the multiplier from the output voltage command value, and gradually reduces the output voltage from the time when the power system returns to normal based on the output of the subtractor. 9. The control device for a generator motor according to claim 6, further comprising: a ramp circuit for approaching the output voltage command value. 10. A generator motor having a primary side connected to a power system, and generator motor voltage control means for controlling an output voltage of the generator motor based on a detected value of an output voltage of the generator motor and an output voltage command value; AC current output means for outputting an AC current having a variable frequency corresponding to the output of the generator motor voltage control means, exciting means for AC exciting the secondary side of the generator motor by the AC current output means, A control device including an accident detection means for detecting occurrence of an accident, and a voltage command value changing means for reducing the output voltage command value in response to the accident detection by the accident detection means, and being connected to the power system. Pumped-storage power generation system. 11. A generator motor having a primary side connected to a power system, and generator motor voltage control means for controlling an output voltage of the generator motor based on a detected value of an output voltage of the generator motor and an output voltage command value, AC current output means for outputting an AC current having a variable frequency corresponding to the output of the generator motor voltage control means, exciting means for AC exciting the secondary side of the generator motor by the AC current output means, A control device including an accident detection means for detecting occurrence of an accident, and a voltage command value changing means for reducing the output voltage command value in response to the accident detection by the accident detection means, and being connected to the power system. Features a flywheel power generation system.