JPH04314975A - Start controller for governorless water turbine - Google Patents

Abstract

PURPOSE:To carry out the starting and parallel operation smoothly according to the magnitude of the head of a goernorless water turbine. CONSTITUTION:A fuzzy controller for controlling a servomotor is installed so as to adjust the opening/closing time of a guide vane, according to the magnitude of the head, and a governorless water turbine is smoothly started by opening the guide vane slowly or speedily according to the magnitude of the head on start, and when the revolution speed S of the water turbine becomes close to the rated revolution speed, the rated revolution speed is realized smoothly by operating the guide vane opening degree G little by little, and parallel operation is carried out.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start-up control device for controlling the start-up and parallel operation of governor-less water turbines for small and medium-sized hydroelectric power plants.

0002

[Prior Art] Small and medium-sized hydropower plants are waterway power plants in which river water is dammed upstream and guided from the water intake to the power plant through a relatively long waterway to obtain a head difference between them. There are many run-of-river power plants that do not have ponds and generate power according to river flow. Additionally, many small and medium-sized hydropower plants are governorless, meaning they do not use a governor. To start a conventional governor-less water turbine, the starting opening degree is set arbitrarily for the guide vane, and the water turbine is started by opening the guide vane to the starting opening degree using a servo motor regardless of external conditions. After startup, proportional control was performed in response to the deviation between the generator frequency set value and detected value.

0003

[Problems to be Solved by the Invention] Conventional governor-less water turbines automatically open the guide vanes by a servo motor to the starting opening regardless of the head, so when the water level in the water tank is high and the head is large, the water pressure is high and the turbine starts up. At times, the rotational speed of the runner increased rapidly, exceeding the rated rotational speed and overshooting. In addition, when the water level in the water tank is low and the head is small, the water pressure is low, so if the stay vane is clogged with debris, the water turbine may not reach its rated rotational speed even if the servo motor opens the guide vane to the starting opening position. . Furthermore, even after startup, the control device operates the guide vanes at a constant response speed regardless of head, making synchronization difficult if external conditions such as head or water flow change.

SUMMARY OF THE INVENTION An object of the present invention is to provide a startup control device that allows governorless water turbines to be smoothly started and operated in parallel in accordance with the height of the head.

[0005]

[Means for solving the problem] In a start-up control device that controls the start-up and parallel operation of governorless water turbines for small and medium-sized hydroelectric power plants, a servo motor is used to adjust the opening and closing time of guide vanes according to the height of the head. The above object is achieved by providing a fuzzy control device.

In the start control device for a governorless water turbine according to claim 1, the fuzzy control device uses the height of the head or the difference between the rotational speed of the waterwheel and the rated rotational speed as the antecedent, and the opening/closing speed of the governor as the antecedent. If a control rule is provided as a prerequisite, it is suitable for starting the governor-less water turbine smoothly according to the height of the head and bringing it closer to the rated rotation speed.

Furthermore, in the start control device for a governorless water turbine according to claim 1, the fuzzy control device controls the position of the generator coupled to the water turbine and the system when the rotation speed of the water turbine reaches around the rated rotation speed. A control rule in which the phase difference or the frequency difference between the generator and the grid is used as the antecedent part and the opening/closing speed of the governor is used as the consequent part is suitable for smoothly operating governor-less water turbines in parallel.

[0008]

[Operation] As a start control device for a governor-less water turbine, this invention includes a fuzzy control device that controls a servo motor so as to adjust the opening/closing time of the guide vanes according to the height of the head, and when the head is high, the When the vanes are opened slowly and the head is low, the guide vanes can be opened quickly to start the turbine smoothly.

[0009] After startup, when the rotational speed of the water turbine approaches the rated rotational speed, the guide vane opening degree is controlled little by little by the fuzzy control device, so that the waterwheel can smoothly reach the rated rotational speed. .

Furthermore, when the rotation speed of the water turbine reaches around the rated rotation speed, according to a control rule whose antecedent is the phase difference between the generator coupled to the water turbine and the grid or the frequency difference between the generator and the grid. Since the opening and closing of the guide vanes is controlled, the frequency and phase of the generator can be quickly matched to the grid, and the generators can be smoothly synchronized and operated in parallel.

[0011]

[Embodiment] Fuzzy control can be easily expressed in an IF-THEN format (if ~, then do ~), in which the judgment of the process situation is taken as a conditional proposition, and the operation when the proposition is certain is the conclusion. This expression method is a control rule, and the IF part is called the antecedent part, and the THEN part is called the consequent part. The fuzzy control device is composed of a set of multiple fuzzy control rules and a fuzzy inference section. The antecedent variables x1 and x2 of the control rule are called the inputs of the fuzzy control device, and the consequent variable y is called the output. Fuzzy inference is based on fuzzy logic, but fuzzy control uses a simple calculation method that does not use fuzzy relational concepts. This takes into account that, unlike general fuzzy inference in fuzzy logic, in inference in fuzzy control, the input to the fuzzy control device, which is the premise of inference, is not a fuzzy value but an ordinary numerical value. The inference results are also given as numerical values rather than fuzzy values.

[0012] When designing a fuzzy control device, an antecedent part and a consequent part must be determined. In that case, the following is required for the antecedent part. 1) Selection of information for control, ie, antecedent variables x1, x2, etc. of fuzzy control rules. 2) Setting the conditions, that is, determining the fuzzy division of the antecedent variable space. 3) Determination of parameters of fuzzy variables. Since the consequent variable of the consequent part is generally the manipulated variable applied to the plant, it is determined naturally.

The starting control device for a governorless water turbine according to an embodiment of the present invention uses a fuzzy control device to control a servo motor that opens and closes a guide vane. This fuzzy control device uses a programmable controller to
The control rules are: ``If the water level in the water tank is high, open the guide vane slowly,'' and ``If the rotation speed approaches the rated rotation speed, adjust the guide vane opening little by little.'' Start the water wheel smoothly.

[0014] The fuzzy control device according to the present invention has a control rule in which, when the water turbine reaches around the rated rotational speed, "
``If the phase difference between the generator and the grid becomes smaller, the guide vanes should be operated more slowly,'' and ``If the difference between the generator frequency and the grid frequency becomes smaller, the guide vanes should be opened and closed more slowly.'' With this control rule,
To smoothly synchronize generators connected to water turbines and operate them in parallel.

FIG. 1 is a diagram showing the relationship between time and rotational speed during startup of a governorless water turbine equipped with a startup control device according to an embodiment of the present invention. In Figure 1, for reference, straight line A indicates the conventional 65F (frequency) setting value,
Straight line B shows the conventional 77E (guide vane opening degree) selection value. The guide vane opening G of the water turbine is controlled by a fuzzy control device as shown in the figure. First, the governor is opened to the starting opening to start the water turbine. Then, if the water level in the water tank is high, the guide vane is slowly opened and the water turbine is started. When the rotation speed approaches the rated rotation speed, slowly open the guide vane, and when the rotation speed approaches the rated rotation speed, gradually adjust the guide vane opening so that the rotation speed S smoothly reaches the rated rotation speed as shown in the diagram. reach. Furthermore, if the difference between the generator frequency and the grid frequency is small, the guide vanes will be opened more slowly, and if the phase difference between the generator and the grid is small, the guide vanes will be opened even more slowly to synchronize the frequency and phase. and run in parallel. Incidentally, the rotational speed S of the water turbine and the guide vane opening degree G in Fig. 1
are almost the same as the rotational speed and guide vane opening at the time of startup of a conventional water turbine with a governor.

[0016]

According to the present invention, by providing a fuzzy control device as a starting control device for a governorless water turbine, the water turbine is started smoothly according to the height of the head, and when the rotation speed approaches the rated rotation speed, the guide vane is activated. When the opening degree is manipulated little by little and the phase difference and frequency difference between the grid and the generator are small, the guide vane opening degree can be manipulated more slowly to smoothly synchronize and perform parallel operation. According to this invention, it is possible to eliminate the need for a conventionally expensive governor and reduce costs.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between time and rotational speed during startup of a governor-less water turbine equipped with a startup control device according to an embodiment of the present invention.

[Explanation of symbols]

G Guide vane opening S Rotation speed

Claims (3)

[Claims] [Claim 1] A startup control device that controls the startup and parallel operation of governor-less water turbines for small and medium-sized hydroelectric power plants, including fuzzy control that controls a servo motor to adjust the opening and closing time of a guide vane according to the height of the head. A starting control device for a governorless water turbine, characterized in that the device is provided with a device. 2. In the start control device for a governor-less water turbine according to claim 1, the fuzzy control device uses the height of the head or the difference between the rotational speed of the waterwheel and the rated rotational speed as an antecedent, and controls the opening/closing speed of the governor as the antecedent. 1. A start control device for a governor-less water turbine, comprising a control rule as a subject part. 3. The start control device for a governor-less water turbine according to claim 1, wherein the fuzzy control device controls the position of the generator coupled to the water turbine and the system when the rotation speed of the water turbine reaches around the rated rotation speed. 1. A starting control device for a governor-less water turbine, comprising a control rule in which a phase difference or a frequency difference between the generator and the system is an antecedent part, and a governor opening/closing speed is a consequent part.