JPH0861008A - Automatic load controller - Google Patents

Abstract

PURPOSE: To provide an automatic load controller capable of correcting the nonlinearity of a regulating valve and securing a stable followup ability, its control method and power generating system. CONSTITUTION: A governer (synchronous main spindle) position detector 10 detects a signal equivalent to a regulating valve stroke and outputs its detected signal to a corrected value function generator 19. The corrected value function generator 19 outputs a proportion integrator (control loop) gain correction signal to a multiplier 14 based on the detected signal from the governer (synchronous main spindle) position detector 10. Further, the multiplier 14 takes in the corrected signal from the corrrected value function generator 19 and a deviation signal from a deviation calculator 13 for performing deviation calaculation by using signals from a load setter 12 and a power generator detector 21, calculates proportion integration based on these signals and oututs its result to a comparison detection amplifier 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic load control device having a stable turbine load followability when the load changes.

[0002]

2. Description of the Related Art Generally, in a thermal power or nuclear power generation system, as shown in FIG. 5, a turbine 2 having a generator 1 is connected to a boiler 4, and a regulator valve 3 is arranged between them.

The regulator valve 3 controls the flow rate of main steam flowing from the boiler 4 into the turbine 2, and is connected to the governor 8 via a cam mechanism and a hydraulic mechanism.

The governor 8 is driven by a governor motor 9, and the position at that time is detected by a governor position detector 10.

In the power generation system, the load setter 12 for determining the opening degree command of the regulator valve 3 driven by the governor 8.
The deviation calculator 13 that performs the deviation calculation between the generator output detector 21 and the generator output detector 21, the proportional-plus-integral calculator 15 that further performs the proportional-plus-integral calculation, and the automatic load control device 11 include a regulator valve steam flow rate characteristic correction function generator. 17, a regulator valve vapor flow rate characteristic correction inverse function generator 18 and a comparison detection amplifier 16 are incorporated. Here, the function generator 17 and the inverse function generator 18 are for performing stable load follow-up with a constant loop control gain of the turbine output ratio characteristic with respect to the control valve stroke in FIG. The regulator valve is usually a combination valve of 1 to 4 valves, and the steam flow rate is controlled by increasing or decreasing the number of these valves to be opened or switching. The main steam flow rate ratio with respect to the stroke, that is, the turbine output ratio, has a non-linear characteristic. In the example, since the point A is the switching point of the valve, the output change is small and suddenly increases.

Therefore, the turbine output change with respect to the apparent control valve opening command is made constant by the control valve steam flow characteristic correction function generator 17 to the output of the proportional integrator 15.

Related to the above prior art,
For example, Japanese Patent Application Laid-Open No. 1-125503 “Turbine Controller” describes the content of estimating a nonlinear characteristic of a control valve and correcting a valve opening command.

[0008]

By the way, the output Pg of the turbine generator is expressed as follows: Pg = k.w.Δi where k: constant w: main steam flow rate (excluding turbine extraction flow rate) Δi: heat drop enthalpy And the heat drop enthalpy Δi depends on the condenser vacuum.

The actual confirmation of the control valve steam flow rate characteristic is performed by the governor motor 9 by the governor (synchronous spindle) position detector 10 and the generator output detector 21. The influence of the condenser vacuum degree, Effect on generator output due to system frequency fluctuation, cam mechanism by annual periodic inspection and disassembly,
Deviation of the hydraulic mechanism may affect the position of the governor (synchronous spindle), resulting in inaccuracy. Moreover, it is necessary to confirm the trial run at the time of annual regular inspection, which is extremely complicated.

Further, due to lack of accuracy and deviation of characteristics, as shown in FIG. 3, responsiveness of the generator output (MW) to the load command (MWD) deteriorates and hunting occurs near the point A passage. .

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic load control device having a stable turbine load followability when the load changes, in view of such circumstances.

[0012]

An automatic load control system according to a first aspect of the present invention detects the position of a regulator valve that regulates the flow rate of main steam supplied to a turbine and a governor that regulates the opening degree of the regulator valve. In an automatic load control device that has a governor position detector that automatically controls the governor position based on the detection signal from the governor position detector and the control valve opening / closing command, It is characterized in that a correction means for correcting the gain of the integrator based on the governor position is provided.

Further, the correction means includes a gain correction function generator which outputs a gain correction signal based on a detection signal of the governor position detector, and a deviation between the load command of the generator output and the generator output, which is used for the correction. And a multiplier that multiplies the gain correction signal output by the function generator.

Further, the gain correction function generator outputs a correction signal such that the gain of the proportional integrator becomes lower than that in a normal time when the control valve is switched. .

[0015]

In the automatic load control device or the power generation system having the above structure, the control gain can be easily corrected and stable turbine load followability even when the generator load hunts due to the nonlinear characteristic of the regulator valve when the load changes. Can be maintained.

In particular, when the control valve is being switched,
Since the gain of the proportional integrator is set to be lower than that in the normal time, it is possible to reduce excessive overshoot and undershoot that accompany a load change that occurs when the control valve is switched.

[0017]

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

FIG. 1 shows the configuration of an embodiment of a power generation system to which an automatic load control device according to the present invention is applied. As shown in FIG. 1, the characteristic part of the present invention is that an automatic load control device 1
1, a multiplier 14 and a gain correction value function generator 19 are provided, and the correction value function generator 19 causes the proportional-plus-integral calculator 15 to operate.
The gain correction is performed and the regulator valve steam flow rate characteristic correction function generators 17 and 18 are stopped, and other configurations are the same as those of the conventional example shown in FIG. In the above configuration, the governor (synchronous main shaft) position detector 10 detects a signal corresponding to the adjusting valve stroke and outputs the detection signal to the correction value function generator 19.

The correction value function generator 19 outputs a proportional integrator (control loop) gain correction signal to the multiplier 14 based on the detection signal from the governor (synchronous spindle) position detector 10.

Further, in the arithmetic unit 14, the deviation arithmetic unit 1 for performing the deviation calculation based on the correction signal from the correction value function generator 19 and the signals from the load setting unit 12 and the generator output detector 21.
The deviation signal from 3 is taken in, proportional-integral calculation is performed based on these signals, and the result is output to the comparison detection amplifier 16. In this embodiment, the multiplier 14, the correction value function generator 19 and the governor (synchronous spindle) position detector 10 are used.
It constitutes a correction means.

According to the automatic load control device having the above-mentioned configuration, the gain of the control loop can be optimally set according to the change in the control valve steam flow rate characteristic. The principle will be described below.

FIG. 6 is a characteristic diagram of the gain correction of the proportional integrator (control loop) with respect to the governor (synchronous spindle) position. As shown in the characteristic table of control valve speed relay stroke to turbine output ratio in Fig. 2, point A at which control valve is switched
In the vicinity, the control gain for varying the turbine output is lowered to effectively suppress hunting when the load changes.

In this operation, the load is set by the load setter 12, and the deviation calculator 13 and the proportional-plus-integral calculator 15 perform control so that the feedback signal from the generator output detector 21 matches the target value. This is the basic control method. However, the optimum control gain of this proportional-plus-integral calculator is
Although it is determined as an average value from the turbine output ratio gain (slope) and response characteristics in the characteristic table of FIG. 2, where the turbine output ratio gain (slope) suddenly fluctuates, such as around point A. , Deviation signal ΔM from deviation calculator 13
It is necessary to correct the gain of W to a low level by the multiplier 14. It is the gain correction function generator 19 that inputs the signal from the governor position detector + valve reduction speed relay stroke) 10 that sets the correction gain of this multiplier. The configuration and contents of the gain correction means are such that the deviation signal ΔMW from the deviation calculator 13 and the correction signal output K from the gain correction function modification generator 19 are multiplied by the multiplier 14 to obtain the corrected deviation signal K · ΔMW. by. This signal is proportional-integrally calculated by the proportional-plus-integral calculator 15 to obtain the corrected governor position.
(Adjustment valve opening) command (KP ・ K ・ ΔMW + ∫K ・ ΔMWd
t / TI). This effect is shown in a time chart of FIG. 4, and it can be seen that the effect is improved as compared with FIG. 3 of the conventional technique. As shown in FIG. 4, this correction means suppresses overshoot and undershoot of the control signal for controlling the opening degree of the steam control valve. However, in the control method in which the proportional integral calculation is the basic control method, disturbance or Overshoot and undershoot always occur when the setting is changed. The deviation signal ΔMW determines the amount of overshoot and undershoot.
And the proportional gain setting of the proportional-plus-integral calculator and the integral gain (time) setting. The setting value from now on is ZIEGLER NI
Although CHOLS has experimentally determined the optimal solution from the response to step changes, it is difficult to do this in a small operating range with an actual machine.

Therefore, paying attention to the deviation signal ΔMW, as described above, the overshoot and the undershoot are expected to become large in a portion where the turbine output ratio gain (slope) changes rapidly as in the vicinity of the point A. Therefore, the correction gain K Is set to a low value and the deviation signal K
ΔMW is suppressed and overshoot and undershoot are suppressed. In addition, even if the nonlinear characteristics of the control valve cannot be measured accurately, even if the characteristics deviate due to aging due to annual inspections etc., the gain of the governor (synchronous spindle) position can be easily monitored online by checking the hunting situation. Can be adjusted to

[0025]

As described above, according to the present invention, the control loop gain is corrected on the basis of the governor (synchronous main shaft) position signal, so that the nonlinear characteristic of the regulator valve can be accurately determined. When the characteristics cannot be grasped or the characteristics deviate due to aging, adjustment is simple and stable turbine load followability with load changes can be secured.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a power generation system to which an automatic load control device according to the present invention is applied.

FIG. 2 is a characteristic diagram showing an opening characteristic, a main steam amount ratio, and a turbine output ratio characteristic of a combination regulating valve with respect to a speed relay stroke for regulating valve of the automatic load control system shown in FIG.

FIG. 3 is a characteristic diagram showing a relationship of followability of a generator output (MW) with respect to a load command (MWD) of the conventional automatic load control device shown in FIG.

FIG. 4 is a characteristic diagram showing a relationship of followability of a generator output (MW) with respect to a load command (MWD) of the automatic load control device of the present invention shown in FIG.

FIG. 5 is a configuration diagram showing a power generation system in which a conventional automatic load control device is installed.

FIG. 6 is a characteristic diagram showing the relationship of the gain correction of the proportional integrator with respect to the governor (synchronous spindle) position of the automatic load control system of the invention.

[Explanation of symbols]

1 ... Generator, 2 ... Turbine, 3 ... Control valve, 4 ... Boiler,
8 ... Governor, 9 ... Governor motor, 10 ... Governor position detector, 11 ... Automatic load control device, 12 ... Load setting device, 13
... deviation calculator, 14 ... multiplier, 15 ... proportional-plus-integral calculator,
Reference numeral 16 is a comparative detection amplifier, 17 is a regulator valve steam flow rate characteristic correction function generator, 18 is a control valve vapor flow rate characteristic correction inverse function generator, 19 is a gain correction function generator, 21 is a generator output detector.

Claims (3)

[Claims] 1. An opening command of a regulator valve for adjusting a main steam flow rate to be supplied to a turbine is obtained by a proportional integral calculation of a deviation between a generator output load command and the generator output, and this opening command signal is used. In the automatic load control device that has a governor position detector that detects the position of the governor that adjusts the opening degree of the regulator valve, and controls the governor position based on a detection signal from the governor position detector, the proportional An automatic load control device comprising: a correction unit that corrects a gain of an integrator based on a governor position. 2. The correction means calculates a gain correction function generator that outputs a gain correction signal based on a detection signal of the governor position detector, and a deviation between a load command of the generator output and a generator output. The automatic load control device according to claim 1, further comprising: a multiplier that multiplies the gain correction signal output by the gain correction function generator. 3. The gain correction function generator is configured to output a correction signal such that the gain of the proportional integrator is lower than that in a normal time when the control valve is switched. The automatic load control device according to claim 2.