JP2002218657A - Power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generation system by which a request for a high quality power can be met at a lower equipment cost. SOLUTION: In the power generation system wherein an ac power generated by a generator driven by a prime mover is converted to a rated frequency of a power system by a frequency converter and wherein the fuel supply to the prime mover is operated by a governor, the power generation system comprises a means to detect the frequency of the power system or to receive the frequency from an external device, a means to adjust an active power supplied to the power system via the frequency converter so that the frequency of the power system detected or received may agree with the rated frequency, a means to detect the number of revolutions of the generator, and a means to adjust power produced by the prime mover through adjustment of the fuel supply of the governor so that the number of revolutions of the generator detected by the means to detect the number of revolutions may coincide with the predetermined target number of revolutions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generation system for supplying AC power from a plurality of distributed generators.

[0002]

2. Description of the Related Art A conventional commercial or private power generator has a rotating speed synchronized with the frequency of an AC system, for example, 30 rpm.
It was operated at 00 rpm or 3600 rpm, and was configured to stabilize the voltage by an automatic voltage regulator (AVR), the power by a power stabilizer (PSS), and the frequency by a governor. In this case, even in an automatic voltage regulator or a power stabilizing device whose operation speed is faster than that of a cabana, the operation changes the field inside the generator through a current change in a rotor winding having a time constant of about 10 seconds. Therefore, the time constant of the voltage control is about 0.2 seconds, and the time constant of the power control is about 1.0 seconds. Further, in the frequency control, the response speed is about several seconds due to the governor operation limitation. As a result, it was not possible to sufficiently cope with frequency and voltage fluctuations caused by sudden changes in load, and flywheels and batteries were employed to prevent sudden changes in frequency and voltage fluctuations.

When the flywheel and the storage battery require kinetic energy and energy stored in the battery, respectively, they output AC power through a frequency converter composed of a thyristor rectifier or the like. Since the thyristor rectifier has a response speed of millisecond, power control also has a response speed of millisecond. Therefore, it is possible to quickly compensate for voltage fluctuations and frequency fluctuations caused by sudden changes in the load.
However, flywheels and storage batteries are loads that consume little power except for accidents, and their equipment costs are not low.

[0004]

In the above-described conventional power generation system, it is impossible to control sudden changes in frequency and voltage, and to cope with a demand for high-quality power supply that requires a constant voltage and a constant frequency. There was a problem that it could not be done. In addition, devices for ensuring high-quality power, such as flywheels and storage batteries, have a problem that performance is good but costs are high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a power generation system capable of meeting a demand for high-quality power supply at a lower facility cost than a conventional power generation system. The purpose is to do.

[0006]

According to the first aspect of the present invention,
A power generator comprising: a generator; a prime mover for driving the generator; a frequency converter for converting AC power generated by the generator into a rated frequency of a power system; and a governor for controlling a fuel supply amount to the prime mover. In the system, means for detecting the frequency of the power system or receiving from an external device, and the active power supplied to the power system via the frequency converter so that the detected or received frequency of the power system matches the rated frequency. Active power adjusting means for adjusting, rotating speed detecting means for detecting the rotating speed of the generator, and governor such that the rotating speed of the generator detected by the rotating speed detecting means coincides with a preset target rotational speed value. And a generated power adjusting means for adjusting the generated power of the prime mover by adjusting the fuel supply amount.

According to a second aspect of the present invention, in the power generation system according to the first aspect, the active power adjusting means is supplied to the power system when the detected or received frequency of the power system is lower than the rated frequency. The active power is increased, and when the frequency of the power system is higher than the rated frequency, the active power supplied to the power system is reduced.

According to a third aspect of the present invention, in the electric power generation system according to the second aspect, the active power adjusting means further includes a rotation speed change amount of the generator based on the rotation speed detected by the rotation speed detection means. And the rotation rate change rate,
When at least one of the rotation speed change amount and the rotation speed change rate exceeds a preset limit range, the change in the rotation speed and the change in the rotation speed take precedence over the active power control for matching the frequency of the power system to the rated frequency. It has a function of executing active power control based on at least one of the rates.

According to a fourth aspect of the present invention, in the power generation system according to the first aspect, means for detecting the voltage of the power system or receiving the voltage from the external device, and the detected or received voltage of the power system is more than the system voltage target value. The reactive power supplied to the power system when the power system voltage is low, and decreases the reactive power supplied to the power system when the voltage of the power system is higher than the system voltage target value. Things.

According to a fifth aspect of the present invention, in the electric power generation system according to the first aspect, the generated power adjusting means further includes a power generated by the prime mover when the detected or received frequency of the power system is lower than the rated frequency. And when the frequency of the power system is higher than the rated frequency, the power generated by the prime mover is reduced.

According to a sixth aspect of the present invention, in the electric power generation system according to the fifth aspect, the generated power adjusting means further includes a generator speed change amount based on the speed detected by the speed detector. And the rotation rate change rate,
It has a limiting function of limiting at least one of the rotation speed change amount and the rotation speed change rate to a predetermined range.

According to a seventh aspect of the present invention, in the power generation system according to the sixth aspect, the generated power adjusting means further includes a limit range in which at least one of the rotation speed change amount and the rotation speed change rate is set in advance. When it exceeds, the rotation speed control by at least one of the rotation speed change amount and the rotation speed change rate is prioritized to control the rotation speed so that the rotation speed of the generator matches the preset rotation speed target value. It has a function to execute.

According to an eighth aspect of the present invention, in the power generation system according to the fifth aspect, the generated power adjusting means has a function of controlling the rotation speed of the prime mover according to the active power.

According to a ninth aspect of the present invention, in the electric power generating system according to the eighth aspect, the generated power adjusting means inputs the amount of air supplied to the combustor and the target output value of the prime mover to supply fuel to the prime mover. It adjusts the supply amount.

According to a tenth aspect of the present invention, in the electric power generation system according to the ninth aspect, the prime mover includes a turbine and an air compressor, and the generated power adjusting means operates the rotation speed of the air compressor or a bleed valve. This suddenly changes the output of the prime mover.

According to an eleventh aspect of the present invention, in the electric power generation system according to the first aspect, the active power adjusting means controls the frequency so as to keep the amount of power received from the power system substantially constant for a predetermined load system. It adjusts the active power supplied to the power system via the converter.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a system diagram showing a schematic configuration of an embodiment of a power generation system according to the present invention. In the figure, a prime mover 1 is coupled to drive a generator 2. Further, a frequency converter 3 that controls the primary current of the generator 2 and supplies the primary current to the power system 10 is provided.

Further, a governor 4 is provided for adjusting the fuel supply amount of the prime mover 1, and furthermore, the rotation speed of the prime mover 1 or the generator 2 (since they are integrally connected, the present invention A governor control device 5 is provided as a generating power adjusting unit that receives a rotational speed detection value by a rotational speed detecting unit (not shown) and outputs an operation command to the governor 4.

On the other hand, a frequency detecting means (not shown) or an active power adjusting means for adjusting the active power supplied to the power system in accordance with a frequency signal of the power system obtained from an external device is also omitted. And a reactive power adjusting means for adjusting the reactive power supplied to the power system in accordance with the voltage detecting means or the power system voltage signal obtained from the external device.

FIG. 2 is a system diagram showing a detailed configuration of the prime mover 1, the generator 2, and the frequency converter 3 shown in FIG. Here, the prime mover 1 is constituted by the compressor 7, the turbine 8 and the combustor 9. The generator 2 is a permanent magnet type generator having no excitation circuit. The frequency converter 3 is a generator 2
Is an inverter that converts the high-frequency three-phase alternating current generated in step (1) into an alternating current of 50 Hz and supplies it to the power system 10.

The schematic operation of the present embodiment configured as described above will be described below. First, when the frequency of the system decreases or increases due to a sudden change in the load, the frequency converter 3 and the frequency converter control device 6 adjust the active power supply amount according to the detected frequency change to change the frequency. To compensate. If this increases the available active power,
The rotation speed of the generator 2 decreases. Normally, the rotational energy of the generator 2 has reached an amount capable of outputting the rated load for several seconds. By converting this rotational energy into active power, it is possible to cope with a frequency change at the time of a system failure or a sudden increase in load. A large output can be supplied to the power system 10 for several seconds.

Next, when the voltage of the system drops or rises due to a sudden change in the load, the frequency converter 3 and the frequency converter controller 6 adjust the reactive power supply amount according to the detected voltage to adjust the voltage. Compensate for changes.

On the other hand, the governor 4 and the governor control device 5 detect the rotational speed of the prime mover 1 or the generator 2 and, in accordance with the deviation from the target value, the fuel supply amount to the prime mover 1 so that the deviation becomes zero. Control. That is, when the rotation speed is lower than the target value, the output of the prime mover 1 is increased by increasing the fuel supply amount from the governor 4 to recover the rotation speed. Conversely, when the rotation speed is equal to or higher than the target value, the fuel supply amount is reduced to increase the output of the prime mover 1 to control the rotation speed to the target level. Thus, the cooperative operation of the control of the frequency converter 3 and the control of the generator 2 allows
Suppress frequency fluctuations in the system. Also, when voltage fluctuations occur, control can be performed in the same manner.

FIG. 3 is a block diagram showing a detailed configuration of the governor control device 5 for controlling the prime mover 1. Here, the function generator 11 inputs the generator output set value and outputs a target rotational speed value corresponding to the set value, and corresponds to the scheduling control function of the present invention.
The subtractor 12 receives one of the rotation speed detection values as input and the rotation speed target value as the other input, and subtracts the rotation speed detection value from the rotation speed target value, and adds the difference signal to the PID calculator 13. The PID calculator 13 executes each operation of proportionality, integration, and differentiation on the input deviation signal, adds the results, and outputs the result as a fuel flow target value. The subtractor 14 receives the fuel flow target value as one input, the actual fuel flow detection value as the other input, subtracts the fuel flow detection value from the fuel flow target value, and adds the deviation signal to the PID calculator 15. .
The PID calculator 15 is proportional to the input deviation signal,
Each operation of integration and differentiation is executed, the results are added, and the result is output as a governor valve opening instruction value.

According to this configuration, the prime mover 1 or the generator 2
And the target rotational speed value pre-scheduled from the generator output set value, that is, the rotational speed target value output via the function generator 11
2 and the difference is added to the PID calculator 13. Then, the PID calculator 13 outputs a fuel flow rate target value that makes the deviation close to zero. This fuel flow target value is compared with the fuel flow measurement value by the subtractor 14, and the deviation is added to the PID calculator 15. Then, the PID calculator 15 outputs an opening instruction value of the fuel flow control valve of the governor 4 so that the deviation approaches zero. By such control, the rotation speed of the generator 2 can be controlled to the rotation speed target value.

FIG. 4 is a block diagram showing a detailed configuration of the active power adjusting means constituting the frequency converter control device 6. As shown in FIG. Here, the subtractor 21 receives the system frequency signal detected or received from the external device as one input, and the rated frequency signal of the power system 10 as the other input, subtracts the system frequency signal from the rated frequency signal, and calculates the deviation signal by PID calculation. To the vessel 22. The PID calculator 22 performs each operation of proportionality, integration, and differentiation on the input deviation signal, adds the results, and outputs the result as an active power instruction value. The rotation speed limiter 23 suppresses a change in the rotation speed of the generator 2 as much as possible and, when the rotation speed change amount exceeds the limit range, executes control that gives priority to the output of the PID calculator 22. A rotation speed signal of the machine 2 is input, and its magnitude is zero in a predetermined range, rapidly rises in a region exceeding the lower limit of this range, and rapidly falls in a region exceeding the upper limit, according to a rotation speed limiting function. It outputs the active power instruction value.

On the other hand, in order to minimize the change in the rate of change of the number of revolutions of the generator 2 and, when the rate of change of the number of revolutions exceeds the limit range, to execute control giving priority to the output of the PID calculator 22. , A differentiator 24 and a rotation speed change rate limiter 25 are provided. Among them, the differentiator 24 receives a rotation speed signal of the generator 2, differentiates this signal to generate a rotation speed change rate signal, and applies the signal to the rotation speed change rate limiter 25. The rotation rate change rate limiter 25 has an input change rate signal which is zero in a predetermined range centered on the zero point, rapidly rises in a region exceeding the lower limit of this range, and rapidly rises in a region exceeding the upper limit. It outputs an active power instruction value according to a decreasing rotation speed change rate limiting function.

The adder 26 adds the active power values output from the PID calculator 22, the rotation speed limiter 23, and the rotation speed change rate limiter 25, and adds them to the frequency converter 3 as an active power indication value. is there.

With this configuration, the active power instruction value for maintaining the frequency of the power system at the rated frequency, the active power instruction value for controlling the generator rotation speed within the limit value, and the rate of change of the rotation speed are set to predetermined values. The active power instruction value to be controlled within the range is added to obtain an active power output instruction value. This active power output instruction value is provided to frequency converter 3. Frequency converter 3 outputs active power according to the active power output instruction value.
The operation of the frequency converter 3 with respect to the active power output instruction value is a known technique, and a description thereof will be omitted here.

FIG. 5 is a block diagram showing a detailed configuration of the reactive power adjusting means constituting the frequency converter control device 6. In the figure, a subtractor 31 receives a detected value of a system voltage applied from a system voltage detecting means (not shown) or an external device as one input, a preset system voltage target value as the other input, and outputs a system voltage target value from the system voltage target value. The voltage detection value is subtracted, and the difference is added to the PID calculator 32. PID
The arithmetic unit 32 performs the respective operations of proportionality, integration and differentiation on the deviation inputted thereto, outputs a corrected value of the reactive power, and adds it to the adder 33. The adder 33 adds the reactive power correction value to the reactive power target value and outputs a reactive power instruction value, thereby controlling the frequency converter 3.

With this configuration, the reactive power supplied to the power system is increased when the voltage of the power system is lower than the system voltage target value, and is increased when the voltage of the power system is higher than the system voltage target value. Can reduce the reactive power supplied to the power system, and prompt voltage compensation is possible.

FIG. 6 is a graph showing the operation of the governor when there is a difference between the detected or given frequency detection value and the rated frequency in order to further enhance the response performance for compensating for the frequency fluctuation of the power system. FIG. 9 is a block diagram showing a configuration of another embodiment in which the elements shown by broken lines 40 are added to the governor control device 5 so as to make the configuration as shown in FIG. In the figure, a subtractor 41 has a system frequency detection means (not shown) or a system frequency detection value applied from an external device as one input and a rated frequency as the other input, and subtracts the system frequency detection value from the rated frequency to obtain the deviation. The minute is added to the PID calculator 42. The PID calculator 42 executes the respective calculations of proportionality, integration, and differentiation on the deviation input thereto, outputs a governor valve opening correction value, and adds the corrected value to the adder 43. The adder 43 adds the governor valve opening correction value to the valve opening instruction value output from the PID calculator 15 and outputs a corrected governor valve opening instruction value, thereby operating the governor 4.

With this configuration, when the detected or received power system frequency is lower than the rated frequency, the power generated by the prime mover 1 is increased, and when the power system frequency is higher than the rated frequency, the prime mover 1 is increased. Can be reduced, and the frequency compensation can be performed more quickly by the feedforward control than in the above embodiment.

FIG. 7 shows that the amount of change in the number of revolutions and the rate of change in the number of revolutions of the generator 2 are kept constant within a predetermined range, and when the range is exceeded, the governor opening instruction value output from the PID calculator 15 is changed. This embodiment is for outputting a governor opening degree instruction value based on the rotation speed change amount and the rotation speed change rate with priority, and shows another embodiment in which an element indicated by a broken line 50 is added to the governor control device 5. ing.

Here, the rotational speed limiter 51, the differentiator 52,
The rotational speed change rate limiter 53 and the adder 54 are each shown in FIG.
Has the same functions as the rotation speed limiter 23, the differentiator 24, the rotation speed change rate limiter 25, and the adder 26 shown in FIG. On the other hand, this embodiment is different in that the present embodiment is configured to compensate for the governor valve opening instruction value.

With this configuration, it is possible to control to limit at least one of the amount of change in the number of revolutions and the rate of change in the number of revolutions of the generator 2 to a preset range. Further, when at least one of the rotation speed change amount and the rotation speed change rate exceeds a predetermined limit range, the rotation speed control is performed so that the rotation speed of the generator 2 matches the preset rotation speed target value. , The rotation speed control based on at least one of the rotation speed change amount and the rotation speed change rate can be executed.

FIG. 8 shows a specific application example of the power generation system according to the present invention. In the power generation system, a building 63 as a load system receives power from a power system 61 via a transformer 62, and a power generation system. Generator 6 that constitutes the system
4 also shows a case where power is received. In this case, a control function as shown in FIG. 9 is provided in the frequency converter control device 6 so as to keep the power received from the power system 61 substantially constant. Here, the subtracter 71 subtracts a load power detection value detected by a power meter (not shown) from a predetermined received power set value, and adds the difference to the PID calculator 72.
The PID calculator 72 executes each operation of proportionality, integration and differentiation with respect to the deviation inputted thereto, and outputs an active power instruction value to be output by the generator 64.

With this configuration, when the load power A temporarily increases as shown in FIG. 10 showing the relationship between time and active power, the generated power B corresponds to this increase.
Therefore, the received power C can be kept substantially constant.

In the above-described embodiment, the case where the governor is controlled by the control valve in order to control the output of the prime mover has been described. Can also be realized by controlling the rotation speed of the variable speed pump. When the rotation speed of the compressor 7 of the turbine 8 is variable,
The output of the prime mover 1 can be changed quickly by changing the rotation speed to increase or decrease the air inflow amount, or by changing the required power of the compressor 7 by operating the bleed valve. .

[0040]

As is apparent from the above description, according to the present invention, a power generation system capable of meeting the demand for high quality power supply with lower equipment cost than the conventional high quality power generation system. Can be provided.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a schematic configuration of an embodiment of a power generation system according to the present invention.

FIG. 2 is a system diagram showing a detailed configuration of main elements of the power generation system shown in FIG.

FIG. 3 is a block diagram showing a detailed configuration of a governor control device for controlling a prime mover of the power generation system shown in FIG. 1;

FIG. 4 is a block diagram showing a detailed configuration of active power adjusting means constituting a frequency converter control device for controlling the frequency converter of the power generation system shown in FIG. 1;

FIG. 5 is a block diagram showing a detailed configuration of a reactive power adjusting unit included in the frequency converter control device for controlling the frequency converter of the power generation system shown in FIG. 1;

FIG. 6 is a block diagram showing another configuration example of the governor control device for controlling the prime mover of the power generation system shown in FIG. 1;

7 is a block diagram showing another example of the configuration of the governor control device for controlling the prime mover of the power generation system shown in FIG. 1.

FIG. 8 is a power receiving system diagram showing a specific application example of the power generation system according to the present invention.

FIG. 9 is a block diagram showing a detailed configuration of an active power adjusting unit included in the frequency converter control device corresponding to the power receiving system shown in FIG. 8;

FIG. 10 is a diagram showing a relationship between time and active power for explaining the operation of the power generation system shown in FIG. 8;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 motor 2 '64 generator 3 frequency converter 4 governor 5 governor controller 6 frequency converter controller 7 compressor 8 turbine 9 combustor 10 '61 power system 11 function generator 12, 14, 21, 31, 41, 41 71 Subtractor 13, 15, 22, 32, 42, 72 PID calculator 23, 51 Revolution speed limiter 24, 52 Differentiator 25, 53 Revolution speed change rate limiter 26, 33, 43, 54 Adder 62 Transformer 63 Building

Continuation of the front page (72) Inventor Juichi Fukakura 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture F-term in Toshiba Keihin Works (reference) 5G066 HA01 HA19 HA30 HB02 HB04

Claims (11)

[Claims] 1. A generator, a prime mover for driving the generator, a frequency converter for converting AC power generated by the generator into a rated frequency of a power system, and a fuel supply amount to the prime mover. A power generator system comprising: a governor that detects the frequency of the power system or receives the power from the external device; and a power converter via the frequency converter so that the detected or received frequency of the power system matches the rated frequency. Active power adjusting means for adjusting the active power supplied to the grid; rotating speed detecting means for detecting the rotating speed of the generator; and the rotating speed of the generator detected by the rotating speed detecting means is preset. A power generation system comprising: a generation power adjustment unit configured to adjust a fuel supply amount of the governor to adjust a generation power of the prime mover so as to match a target rotation speed value. 2. The active power adjusting means increases the active power supplied to the power system when the frequency of the detected or received power system is lower than the rated frequency, and the frequency of the power system is higher than the rated frequency. 2. The power generation system according to claim 1, wherein the active power supplied to the power system is reduced. 3. The active power adjusting means further calculates a rotation speed change amount and a rotation speed change rate of the generator based on the rotation speed detected by the rotation speed detection means, and calculates the rotation speed change amount. When at least one of the rotation speed change rate exceeds a preset limit range, at least the rotation speed change amount and the rotation speed change rate in preference to active power control to match the frequency of the power system to the rated frequency. The power generation system according to claim 2, further comprising a function of performing active power control by one of the power generation systems. And means for detecting the voltage of the power system or receiving the voltage from the external device; and increasing the reactive power supplied to the power system when the detected or received voltage of the power system is lower than the system voltage target value. The power generation system according to claim 1, further comprising: a reactive power adjustment unit configured to reduce reactive power supplied to the power system when a voltage of the system is higher than a system voltage target value. 5. The generated power adjusting means further increases the generated power of the prime mover when the detected or received frequency of the power system is lower than a rated frequency, and when the frequency of the power system is higher than the rated frequency. The power generation system according to claim 1, further comprising a function of reducing power generated by the motor. 6. The generated power adjusting means further calculates a rotation speed change amount and a rotation speed change rate of the generator based on the rotation speed detected by the rotation speed detection means, and calculates the rotation speed change amount. The power generation system according to claim 5, further comprising a restriction function of restricting at least one of a rotation speed change rate and a rotation speed change rate to a preset range. 7. The generator power adjusting means, further comprising: when at least one of the rotation speed change amount and the rotation speed change rate exceeds a predetermined limit range, the generator rotation speed is set to the predetermined rotation speed. 7. The electric power generation system according to claim 6, further comprising a function of executing a rotation speed control based on at least one of the rotation speed change amount and the rotation speed change rate, prior to performing the rotation speed control so as to coincide with the numerical target value. system. 8. The electric power generation system according to claim 5, wherein said generated power adjustment means has a scheduling control function of a rotation speed of a motor according to active power. 9. The electric power generation system according to claim 8, wherein said generated power adjusting means adjusts a fuel supply amount to said motor by inputting an air supply amount to a combustor and a motor output target value. 10. The motor according to claim 9, wherein the motor includes a turbine and an air compressor, and the generated power adjusting means changes the output of the motor by operating a rotation speed of the air compressor or a bleed valve. Power generation system. 11. The active power adjusting means adjusts active power supplied to the power system via the frequency converter so as to keep the amount of power received from the power system substantially constant for a predetermined load system. The power generation system according to claim 1.