JPH04304199A - Frequency coordination control method for thermal power plant - Google Patents

Abstract

PURPOSE:To improve frequency coordination by correcting a target load command based on the rotational speed of a turbine employed in a governor controller so that load control through boiler/turbine coordinated control causes no trouble in the frequency regulation of the governor controller thereby suppressing interference between both controls. CONSTITUTION:Frequency is regulated by driving a governor valve 19 based on the fluctuation of the rotational speed 4 of turbine while at the same time load is controlled by driving the governor valve 19 based on the fluctuation of a target load command 2. When such regulation and control are carried out, the target load command 2 is corrected based on the rotational speed 4 of turbine in order to prevent interference between the frequency regulation and the load control based on the target load command 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency coordination control method for a thermal power plant.

0002

2. Description of the Related Art Frequency adjustment of an electric power system involves detecting a deviation of the system frequency from the rated frequency, and driving a governor valve with a governor control device in accordance with the direction of frequency change to change the load. That is, when the system frequency increases relative to the rated frequency, the governor valve is closed to reduce the load, and when the system frequency decreases, the governor valve is opened to increase the load. On the other hand, the load control of the boiler-turbine cooperative control device adds correction based on the frequency so that the load control based on the target load command from the central power supply station does not interfere with the load control (frequency adjustment) by the governor control device. There is.

FIG. 2 shows an example of a conventional control circuit, in which a boiler-turbine cooperative control system detects a target load command a from a central power supply station, and adjusts the frequency of a governor control system in response to this command signal. In order to correct the load fluctuation caused by Create. Furthermore, the generator output f follows the load command signal e.
A governor valve position command i is output to the governor control device via a subtracter g and a proportional/integrator h. In addition, the governor control device detects the turbine rotation speed j and sets the rated frequency setter k.
A deviation l is obtained by a subtractor k equipped with ', and in accordance with the deviation l, a correction signal n is applied to the governor valve position command i from the boiler-turbine cooperative control device via a proportional device m via an adder o. By adding them together, a governor valve command p is obtained, and a governor valve r provided immediately before the turbine q is operated to perform load control. In the figure, s indicates a generator.

That is, the frequency adjustment in the governor control device is as follows:
The governor valve r is driven using the turbine rotation speed j (the turbine rotation speed is the same as the system frequency when the generator is paralleled), and the boiler-turbine cooperative control device uses the system frequency b from the central power supply station. and coordinates with the governor control device.

[0005]

[Problems to be Solved by the Invention] However, in the above conventional system, since the frequency detection points and detectors used in the governor control device and the boiler-turbine cooperative control device are different, there is a gap between the two signals as shown in FIG. A difference t occurs as shown in FIG. This difference is due to the common level difference and the accuracy of the detector.

[0006] For this reason, the load control by the boiler-turbine cooperative control device cannot properly compensate for load fluctuations caused by frequency adjustment by the governor control device, and interference occurs between the two controls.
There was a problem that hindered frequency adjustment.

[0007] The present invention replaces the conventional frequency detection with the turbine rotation speed used in the governor control device so that the load control by boiler-turbine cooperative control does not interfere with the frequency adjustment of the governor control device, thereby minimizing interference between the two controls. , which aims to provide improved frequency regulation.

[0008]

[Means for Solving the Problems] The present invention is an attempt to solve the above-mentioned technical problems.The present invention adjusts the frequency by driving a governor valve based on fluctuations in the turbine rotation speed, and at the same time, controls the target load command. When performing load control by driving the governor valve based on fluctuations in the frequency, by correcting the target load command based on the turbine rotation speed, interference of load control based on the target load command with respect to the frequency adjustment can be avoided. This invention relates to a frequency coordination control method for a thermal power plant, which is characterized in that it prevents.

[0009]

[Operation] Therefore, in the present invention, the target load command is corrected using the turbine rotation speed used for frequency adjustment, so that the load control based on the target load command is can be prevented from interfering with the

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an apparatus for carrying out the method of the present invention, in which a target load command 2 from a central power supply station detected by a detector 1 and a turbine rotation speed 4 detected by a detector 3 are transmitted to a governor. A load command 8 is obtained by leading a correction signal 6 obtained by guiding it to a function converter 5 that converts it into a function representing the fluctuation of load due to frequency adjustment of the control device to an adder 7, and the load command 8 and the power generation The governor position command 1 is set so that the deviation 13 obtained by leading the generator output 11 from the detector 10 that detects the output of the generator 9 to the subtracter 12 becomes zero.
A boiler-turbine cooperative control device is constructed that has a proportional/integrator 15 that outputs 4.

[0012] Also, the turbine rotation speed 4 from the detector 3
, a subtracter 1 having a rated frequency (rotation speed) setter 16
7 to find its frequency deviation 18, and the frequency deviation 1
8, a frequency adjustment signal 21 obtained by a ratio setting proportional device 20 for changing the governor valve 19 and the governor valve position command 14 are added to output a governor valve command 22 to the governor valve 19. A governor control device having an adder 23 having the following configuration is constructed. 24 indicates a turbine.

In the above configuration, the load command 8 is created by using the turbine rotational speed 4 for the target load command 2 and correcting the frequency adjustment by the governor control device by the function converter 5. As a result, the load command 8 is applied to the governor valve 1 by frequency adjustment based on the turbine rotation speed 4 by the governor control device.
A change equivalent to the generator output 11 which is varied by driving the subtractor 9 is obtained, so that the deviation of the subtracter 12 is kept at zero, and the proportional/integrator 15 does not operate. Therefore, the load control of the boiler-turbine cooperative control device does not interfere with the frequency adjustment by the governor control device.

[0014]

As described above, according to the frequency coordination control method for a thermal power plant of the present invention, various excellent effects as described below can be achieved.

(i) By making the frequency signals of the governor control device and the boiler-turbine cooperative control device the same, interference in load control between the two can be reduced and frequency adjustment can be improved.

(ii) Detection of the grid frequency from the central power supply station becomes unnecessary for control purposes.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of an apparatus for implementing the method of the present invention.

FIG. 2 is an explanatory diagram showing an example of a conventional method.

FIG. 3 is a diagram showing signal differences in a conventional method.

[Explanation of symbols]

1 Detector 2 Target load command 3 Detector 4 Turbine rotation speed 5
Function converter 7 Adder 8 Load command 9 Generator 10 Detector 11 Generator output 12 Subtractor 14 Governor position command 15 Proportional/integrator 16 Rated frequency setter 17
Subtractor 19 Governor valve 20 Ratio setting proportional device 21
Frequency adjustment signal 23 Adder 24 Turbine

Claims (1)

[Claims] [Claim 1] Frequency adjustment is performed by driving a governor valve based on fluctuations in turbine rotation speed, and at the same time,
When performing load control by driving the governor valve based on fluctuations in the target load command, the target load command is corrected based on the turbine rotation speed, thereby controlling the load based on the target load command for the frequency adjustment. A frequency coordination control method for a thermal power plant, characterized by preventing interference between the two.