JPS62153573A - Method of driving water turbine - Google Patents

Abstract

PURPOSE:To obtain a large power and a wide operating range from a water turbine generator whose speed is variably controlled, by increasing the rotational speed of a water turbine with the opening degree of the water turbine being held at a constant value. CONSTITUTION:A water turbine 1 drives a generator 2, and is controlled variably in rotational speed by means of a rotational speed control device 3. A control device 4 receives a rotational speed and a guide vane opening degree, and drives the water turbine at a predetermined rotational speed in a range from a minimum guide vane opening degree to a maximum guide vane opening degree, and then controls the water turbine under a given set instruction at a predetermined rotational speed with the guide vane opening degree being held at a constant value. With this arrangement, it is possible to obtain a large output power and a wide operating range with the same water turbine as the conventional one.

Description

[Detailed description of the invention] (a) Industrial application field This invention is a variable-speed controlled water turbine generator, in which the output is increased by changing the rotational speed of a high specific speed Francis turbine or a propeller turbine with fixed runner vanes. Concerning how to operate the water turbine to be adjusted.

(b) Prior art As this type of operating method, the line segment A shown in FIG.
The machine was operating on B at a constant rotation speed while changing the guide vane opening.

However, in this case, since the runner vane is fixed, surging and cavitation occur in the runner vane flow path when the guide vane is opened at a small opening.
The drawback was that the range of operation was limited.

(c) Purpose of the invention This invention has the same specifications as conventional water turbines,
It is an object of the present invention to provide a method of operating a water turbine that can widen the operating range which is limited due to the above-mentioned reasons.

(D) Summary of the Invention In order to achieve the above object, the present invention provides a conventional water turbine of this kind whose characteristics are shown in FIG. The rotation speed was increased using the rotation speed control device, and the rotation speed was increased from point B to 0 point (permissible limit for cavitation occurrence on the runner vane inlet side, runner vane opening range). By operating to the minimum of the permissible limit for cavitation occurrence on the wing surface or the output limit of the generator,
This is an operating method that allows the operating range to be expanded by the increase in output from point B to point 0.

(E) Embodiment FIG. 1 is a diagram for explaining a method of operating a water turbine according to an embodiment of the present invention, in which the water turbine 1 drives a generator 2.

The rotational speed control device 3 performs variable speed control. Control device 4
Input the rotation speed and guide vane opening, and change from the minimum guide vane opening (point A in Figure 2) to the maximum guide vane opening (
It operates at a constant rotation speed up to point B in Figure 2, and then, while keeping the guide vane opening constant, it operates at the given setting until it reaches a predetermined rotation speed (point 0 in Figure 2). Control by command.

By operating this embodiment in this manner, it is possible to obtain larger output and a wider operating range with the same water turbine as the conventional one.

(F) Effects of the Invention As is clear from the above explanation, according to the present invention, by increasing the rotation speed of the water turbine while keeping the guide vane opening constant, the permissible limit of cavitation occurrence on the runner vane inlet pressure side, the runner vane blade surface, etc. It has the advantage that it can be operated to the minimum of the permissible limit of cavitation occurrence or the output limit of the generator, and it is possible to obtain larger output and a wider operating range with the same water turbine as conventional water turbines.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an operation control system of a water turbine according to an embodiment of the present invention, and FIG. 2 is a diagram showing characteristics of this type of water turbine with respect to rotation speed. 1... Water turbine, 2... Generator, 3... Rotation speed control device, 4... Control device.

Claims (1)

[Claims] 1) In a variable speed controlled water turbine generator consisting of a generator and a high specific speed Francis turbine or a propeller turbine with fixed runner vanes that drives the generator, when the water turbine is operated at a constant head, until the guide vane is fully opened, The water turbine is operated at a constant speed, and the guide vane opening is maintained at a constant speed until the minimum of the allowable limit for cavitation at the runner vane inlet, the allowable limit for cavitation on the runner vane blade surface, or the output limit of the generator, whichever is the smallest. A method for operating a water turbine, characterized by increasing the rotation speed of the water turbine using a rotation speed control device.