JPH02252977A - Water level adjustor - Google Patents

Abstract

PURPOSE:To smoothly adjust the water level by the manual operation by a skilled operator by converting the analogue quantity of water level and the power generator output to each fuzzy value and determining the water level adjustment quantity on the basis of the condition of the fuzzy value. CONSTITUTION:A water level adjustor 30 is constituted of a control rule setting part 32 and a fuzzy supposition part 34. The upper water layer water level 20 supplied from a water level detector is inputted into the water level adjustor 30, and the adjustment quantity for the guide vane of a load limitter 22 due to the result of the fuzzy supposition is outputted. Further, the output of the load limitter 22 is utilized for controlling the degree of guide vane opening degree 24, and feedback-operated into the fuzzy supposition part 34 of the water level adjustor 30. Further, the flow-out water quantity 26 is varied by adjusting the guide vane opening degree 24. While, the upper water tank water level 20 which varies according to the flow-out water quality 26, accompanied with the delay time, is detected by the water level detector of the upper water tank.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a water level adjustment device having a fuzzy inference function that can realize stable adjustment control of generator output in response to water level fluctuations in a water tank in hydroelectric power generation. .

[Conventional technology]

In general, a water level adjustment device is a device that adjusts the output of a generator by adjusting the opening degree of the guide vane according to the amount of natural water flowing into the water tank in order to keep the water level of the water tank constant. As a tAN device, one shown in FIG. 3 is known. In FIG. 3, reference numeral 10 is a water level adjustment device, and the water level adjustment device 10 is comprised of a water level setter 12, a PI calculation section 14, a water level adjustment rate calculation section 16, and the like. 2
0 is the water tank water level from the water level detector, 22 is the load limiter of the speed governor, 24 is the guide vane opening degree, and 26 is the outflow water amount.

Adjustment of the water level by the conventional water level adjustment device configured as described above is performed as follows.

The water level adjustment device 10 inputs the upper water tank water level 20, which is the detected value actually obtained by the water level detector, and compares this detected value with the upper water tank water level setting value set in advance in the water level setting device 12. The water level deviation is determined by the water level deviation, and the PI calculation unit 14 performs a proportional-integral (PI) calculation according to the magnitude of the water level deviation, and outputs an adjustment amount to the load limiter 22 so that the water level deviation becomes zero. The load limiter 22 controls the guide vane opening 24 according to this adjustment amount. The outflow water amount 26 changes depending on the guide vane opening degree 24. The upper water tank water level 20, which fluctuates according to the outflow water amount 26 with a delay time, is detected by a water level detector (not shown) of the upper water tank.

Note that there is a time delay between the adjustment of the guide vane opening 24 and the fluctuation of the water tank water level 20, and in order to prevent the amount of adjustment of the load limiter 22 from going too far due to the delay in water level fluctuation, The water level adjustment rate is calculated in the water level adjustment rate calculating section 16 in the water level adjustment device 10, and the load limiter 22
The apparent water level change due to the change in position is added to the detected value of the water tank water level 20 as a correction signal.

[Problem to be solved by the invention]

However, according to the water level adjustment device described above, the water level fluctuation is adjusted by performing a PI calculation according to the size of the water level deviation, which is the difference between the actual water level in the water tank and the set water level in the water level setting device, to limit the load. Since the adjustment amount of the generator is determined, it was difficult to adjust to water level fluctuations that include nonlinear factors, such as changing the number of generators in operation.

In addition, in conventional water level adjustment devices, when the position of the load regulator is changed, a correction signal that changes the apparent water level is calculated by a water level adjustment rate calculation section and added to the detected water tank water level value. If this water level adjustment rate for obtaining a correction signal is not appropriate, there is a problem in that the generator output fluctuates periodically.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a water level side M device that can realize stable adjustment control against nonlinear water level fluctuations and simplify the determination of various parameters necessary for school opening calculations.

[Means to solve the problem]

The water level adjustment device according to the present invention is a water level adjustment device comprising a digital sequence control device that uses a microprocessor to control the generator output of hydroelectric power generation according to the water level of the water tank. The present invention is characterized by comprising a fuzzy inference unit that converts the value into an ambiguous value, and a logic control unit that determines an adjustment amount based on the conditions of the ambiguous value converted by the fuzzy inference unit.

[For production]

According to the water level adjustment device according to the present invention, the fuzzy inference unit calculates analog quantities such as water level and generator output by using a membership function that is a probability function defined for each proposition handled by a fuzzy rule. , into ambiguous values such as "larger" and "smaller", and the logic control unit inputs them based on each ambiguous value, referring to the membership function according to the control rules used for fuzzy control. After combining the results of calculating the degree to which the quantity satisfies the rules,
Compare the consequents of each rule and take the maximum value to create a new membership function, that is, perform the max operation,
Then, the center of gravity of this membership function is calculated to obtain an inference result (center of gravity value), and water level adjustment control is performed based on this inference result. can be incorporated into the water level adjustment device, making it possible to achieve smooth control.

〔Example〕

Next, embodiments of the water level adjusting device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a control block diagram of a water level adjusting device showing one embodiment of the present invention. For convenience of explanation, the same reference numerals are given to the same components as those of the conventional example shown in FIG. 3.

That is, in FIG. 1, reference numeral 30 indicates a water level adjustment device, and the water level adjustment device 30 is a control rule various setting value section 3.
2 and a fuzzy inference section 34. The water tank water level 20 from the water level detector is input to the water level adjustment device 30, and the adjustment amount for the guide vane of the load limiter 22 based on the fuzzy inference result is output. The output of the load limiter 22 controls the adjustment of the guide vane opening 24 and is fed back to the fuzzy inference section of the water level adjustment device 30. The outflow water amount 26 changes depending on the guide vane opening degree 24. The upper water tank water level 20, which fluctuates according to the outflow water amount 26 with a delay time, is detected by the water level detector of the upper water tank.

Here, the water level adjustment device 30 equipped with a fuzzy inference function according to the present invention will be explained.

Broadly speaking, it has the following two functions.

■ Analog quantities such as water level and generator output can be converted into fuzzy
A fuzzy inference function that converts into ambiguous values such as "about half", "large", "small", etc. using the membership function, which is a probability function defined for each proposition handled by the rule.

■ Based on the condition of the ambiguous value converted in ■, according to the control rule used for fuzzy control, the results of calculating the degree to which the input amount satisfies the rule by referring to the membership function are synthesized, and then each rule is The consequent part is compared and the maximum value is taken to create a new membership function, that is, the max operation is performed, and the center of gravity of this membership function is calculated to obtain the inference result (center of gravity value), and this inference result is A logical control function that determines the amount of adjustment to the load limiter guide vanes.

In the fuzzy inference function (■) above, for example, "The water level is currently 7.53 m, which is the set value of 7.20 m."
Instead of doing numerical calculations such as ``The water level is 33 cm higher than the set point,'' you can grasp the general concept of ``The water level is considerably higher than the set value.''

Moreover, the logical control function (2) above makes it possible, for example, to create a control rule such as "If the water level is higher than a set value, increase the generator output" in software.

By combining such fuzzy reasoning and logical control,
The generator output procedure for adjusting the water level is loaded into the fuzzy arithmetic unit as a program of the sequence control device, as shown in the hardware configuration example of the device according to the present invention shown in FIG.

Note that if the sequence control device has sufficient capacity, the fuzzy arithmetic device can be incorporated into the software as a part of the sequence control device. This water level adjustment device uses fuzzy reasoning to control the water level;
Compared to systems that use value-based control or decisions, intermediate, ambiguous states can be used, which allows for flexible and dynamic control, allowing for the ability to encounter situations that have never been experienced before. However, it is also possible to extrapolate and control reasonable conclusions.

The control rules used for fuzzy control in this embodiment are as follows.

(1) If the water level is approximately equal to the set value and the fluctuation of the water level is small, there is no need to adjust the load limiter 22; otherwise, the load limiter 22 is controlled as follows.

(2) If the water level is lower than the water level setting, load limiter 2
Lower the setting of 2.

(3) If the water level is higher than the water level set value, load limiter 2
Increase the setting of 2.

(4) When the water level is far from the set water level,
The settings of the load limiter 22 are changed continuously.

(5) When the water level approaches the set water level to some extent, the settings of the load limiter 22 are changed intermittently little by little.

(6) When switching operations between multiple generators, the adjustment control will not follow even if the water level fluctuates significantly temporarily.

(7) If no change in water level is obtained even though no control signal is applied, it is determined that the load limiter 22 or water level detector 21 has failed, the control output is locked, and the operator Notify of abnormality.

Therefore, after calculating the degree to which the input amount satisfies the rules by referring to the membership function, the converted ambiguous values are calculated according to the control rules used for fuzzy control, and the results are combined to calculate the consequent part of each rule. After performing an operation to create a new membership function by comparing them and taking the maximum value, that is, the max operation, the center of gravity of this membership function is calculated to obtain the inference result (center of gravity value). What is necessary is to determine the adjustment amount for the guide vane.

Note that FIG. 2 is a diagram showing an example of the hardware configuration of the water level adjustment device 30 using fuzzy inference, and is designated by reference numeral 3.
1 is an analog/digital converter (A/D), 33 is a digital sequence controller, 35 is a fuzzy arithmetic unit, 37 is a discrete output interface (Do), 21
23 is a water turbine governor (GOV), and 40 is a man-machine interface consisting of a CRT display, keyboard, blink, etc.

〔Effect of the invention〕

As is clear from the embodiments described above, according to the water level adjustment device of the present invention, by applying fuzzy reasoning, the "ambiguity" of the adjustment amount that water level adjustment control originally has can be directly applied to the software. Since it can be taken in, it is possible to realize smooth control similar to that performed manually by a skilled operator, and it is possible to effectively utilize inflow water at a hydroelectric power plant.

Further, it is not necessary to strictly determine setting values such as a dead zone and an adjustment rate as in the conventional method, and there is an advantage that the determination of various parameters necessary for adjustment calculations can be simplified.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and it goes without saying that various design changes can be made without departing from the spirit of the present invention.

It is.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a water level adjustment device using fuzzy reasoning according to the present invention, and FIG. 2 is a block diagram showing an example of the hardware configuration of a water level adjustment device using fuzzy reasoning according to the present invention. , FIG. 3 is a block diagram showing a conventional water level adjustment device. 1o...Water level adjustment device 12...Water level set value 14...PI calculation unit 16...Water level adjustment rate calculation unit 20...Tap water tank water level 21...Water level detector 22...Load limit Container 23... Water turbine speed governor 24... Guide vane opening degree 26... Outflow water amount 30... Water level adjustment device 31... Analog/digital converter 32... Control rule various set value section 33... Digital sequence control device 34...
Fuzzy inference unit 35...fuzzy arithmetic unit 37...discrete output interface 40...man-machine interface IG. 30

Claims (1)

[Claims] (1) In a water level adjustment device consisting of a digital sequence control device that uses a microprocessor to control the generator output for hydroelectric power generation according to the water level in the water tank, analog quantities of the water level and generator output are converted into ambiguous values. A water level adjustment device comprising: a fuzzy inference section that performs the adjustment; and a logic control section that determines the amount of adjustment based on the condition of the ambiguous value converted by the fuzzy inference section.