JPH03179171A - Control method of water turbine - Google Patents

Abstract

PURPOSE:To make a water turbine safely stoppable by operating a runner vane in the opening direction while operating a guide vane in the closing direction the other way at time of the loss of converter control power, in a device which electrically controls these runner and guide vanes through a converter. CONSTITUTION:At time of usual operation, a signal out of a regulator is inputted into both converters 1, 9, and two main control valves 3, 11 are controlled via each of primary control valves 2, 10. With this operation, pressure oil is fed to each servomotor for both guide and runner vanes from a pressure oil tank 4 by way of a feed oil pipe 5, while drain oil is put back to a sump tank 7 by way of a drain pipe 6, making these guide and runner vanes keep their proper opening. In this case, the converter 1 is regulated so as to become free of closing at time of control power loss and the converter 9 free of opening, respectively, therefore at time of the loss of the control power, the runner vane is operated in the opening direction and the guide vane in the closing direction respectively, through which a water turbine is made so as to be stopped by means of the braking effect of the runner vane.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for controlling a mixed flow water turbine having runner vanes and a propeller water turbine in the event of an abnormality.

(Prior art) Conventionally, in mixed flow water turbines and propeller water turbines, only the guide vanes are controlled by a converter, and the runner vane opening is mechanically controlled via a cam in order to obtain high efficiency over the entire range of the turbine output. In many cases, it was made to follow the guide vane opening. In this case, when the power to the converter was lost, the guide vanes moved in the closing direction, and the runner vanes followed the guide vanes via the cam and also moved in the closing direction.

Furthermore, in converter-controlled high-efficiency control devices (hereinafter referred to as runner vane converter control) that have been adopted in recent years, in which the runner vanes are controlled by a converter, both the guide vanes and runner vanes close automatically when the converter power is lost.

(Problems to be Solved by the Invention) When the runner vane opening is controlled by a mechanical cam to follow the guide vane opening, the following problems occur.

If it is found that high efficiency is not obtained during on-site adjustment tests, it is necessary to remove the cam from the governor and form the cam surface with a grinder or weld overlay, which reduces work efficiency. is very bad, and the period when the water turbine is out of service is extended.

In addition, if a transmission delay occurs due to looseness, warping, wear, etc. of the movable part of the link mechanism that transmits the guide vane opening to the runner vane, the runner vane opening will mismatch the runner vane opening, resulting in insufficient output, vibration, and water pressure fluctuations. Other problems may occur.

Furthermore, when converter power is lost, the guide vanes gradually close and the runner vanes also follow the guide vanes and close, so if the circuit breaker is commanded to open, it will be in a no-load state and the speed increase rate will be large. Since the bearing is not restrained, there is a risk that the bearing temperature will rise and the bearing will be damaged by seizure, or that the stress on rotating parts such as the runner and generator rotor will increase, leading to damage.

The present invention was made in consideration of the above circumstances, and does not require cam adjustment and does not cause rattling in the link mechanism.Furthermore, by stopping the water turbine in a short time, it suppresses the increase in rotation, and the bearing The purpose is to provide a water turbine control method that can protect the water turbines.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a method for controlling a water turbine in which runner vanes and guide vanes are electrically controlled by a converter. The runner vane is moved in the opening direction, while the guide vane is moved in the closing direction.

(Function) Since the present invention electrically controls the runner vanes and guide vanes using a converter, there is no need for a cam or a link mechanism, and as a result, there is no need to adjust the cam, etc., and problems such as play in the link mechanism occur. can be prevented from occurring.

In addition, when converter control power is lost, the runner vanes are moved in the opening direction while the guide vanes are moved in the closing direction, so the runner vanes gradually open (blade-like) to improve the braking effect. This allows the water turbine to be safely stopped.

(Embodiment) An embodiment of the water turbine control method according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a water turbine control device used in the water turbine control method. This control device employs a runner vane converter control system, and FIG. 1 shows the water turbine in a stopped state.

In this control device, during normal operation, a signal from the regulator enters the converter 1, the main pressure distribution valve 3 is controlled via the secondary pressure distribution valve 2, and pressure oil is supplied from the pressure oil tank 4 to the oil supply pipe 5.
The drained oil is sent to a guide vane servo motor (not shown) through the guide vane servo motor (not shown), while the drained oil is returned to the oil collection tank 7 through the oil drain pipe 6, thereby maintaining the guide vane at an appropriate opening degree.

Similarly, in controlling the runner vane, the regulator signal enters the converter 9, the main pressure distribution valve 11 is controlled via the secondary pressure distribution valve 10, and the pressure oil from the pressure oil tank 4 passes through the oil supply pipe 5 to the runner vane servo. While being sent to a motor (not shown), waste oil is returned to the oil collection tank 7 through the oil drain pipe 6, thereby maintaining the runner vane at the most efficient opening.

Next, a method of controlling a water turbine using the above control device will be explained with reference to FIGS. 1 and 2.

First, the guide vane control converter 1 is adjusted so that it will close when control power is lost, and the runner vane control converter 9 is adjusted so that it will open when control power is lost (that is, the runner vane is in an upright state). I'll keep it.

By making this adjustment, when operating under a certain load,
When the control power to the converters 1 and 9 is lost, the electromagnetic force that holds the moving coil 13 is lost, so the coil moves downward due to its own weight, and the guide vane converter 1 moves in the closing direction, causing the negative pressure distribution valve 2 to move downward. The main pressure distribution valve 3 moves in the closing direction via the guide vane servo motor (not shown). This causes the guide vanes (not shown) to gradually close and shut off water.

In parallel with this operation, the converse 9 for runner vane control
The moving coil 14 also moves downward due to its own weight and moves in the opening direction, and the main pressure distribution valve 11 is opened via the -second pressure distribution valve 10.
moves in the opening direction, opening the runner vane servo motor (not shown). As a result, the runner vane gradually becomes open (blade erect).

This state is the state shown in FIG. At this time, since the runner vanes rotate in an upright position, resistance increases and a braking effect is exerted, causing the water turbine to rapidly reduce its rotational speed, and the water wheel is braked at about 30% of its rated speed, coming to a complete stop.

FIG. 2 is a characteristic diagram showing the relationship between the opening degrees of the runner vane and the guide vane and the rotation speed at the time of power loss. As is clear from this figure, when the control power is lost, the opening of the guide vane moves toward the closing direction, while the opening of the runner vane moves toward the opening direction. As a result, the rotation speed of the water turbine rapidly decreases due to the braking effect of the runner vanes, and after about 30% of the rated speed, the water turbine comes to a complete stop due to the braking effect. On the other hand, Fig. 3 is a characteristic diagram showing the relationship between the opening degrees of the runner vane and the guide vane and the rotation speed when the conventional power supply is lost. Following this, the opening degree of the runner vane also moves in the closing direction. As a result, the rotational speed of the water turbine becomes unloaded, the speed increases once, and then gradually decreases.

According to the above embodiment, the runner vanes and guide vanes are electrically controlled by the converters 1 and 9, which eliminates the need for cams and link mechanisms, which improves work efficiency and eliminates problems caused by looseness in the link mechanisms. It is possible to prevent the occurrence of defects.

In addition, when control power is lost, the circuit breaker is commanded to open,
Even in a no-load state, the braking effect of the runner vanes makes it possible to safely and quickly stop the water turbine before it reaches an unrestrained speed. Therefore, damage to the bearing due to an increase in the rotational speed of the water turbine can be prevented.

〔Effect of the invention〕

As explained above, since the runner vanes and guide vanes are electrically controlled by the converter, the present invention eliminates the need for conventional cams and link mechanisms, eliminates the need for cam adjustment, and eliminates play in the link mechanisms. It is possible to prevent the occurrence of problems caused by this.

Further, the present invention provides, when the converter control power supply is lost,
Since the runner vanes are moved in the opening direction while the guide vanes are moved in the closing direction, the water turbine can be stopped safely and quickly due to the braking effect of the runner vanes, and damage to the bearings due to increased rotation speed can be prevented. I can do it.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a control device used in an embodiment of the water turbine control method according to the present invention, and Fig. 2 shows the relationship between the opening degrees of the guide vanes and runner vanes when the converter power supply is lost in the above embodiment, and the opening of the water turbine. Characteristic diagram showing the relationship between rotational speed,
FIG. 3 is a characteristic diagram showing the relationship between the opening degree and the rotation speed of the guide vane and runner vane when the conventional converter power supply is lost. 1.9...Converter, 2.10...-Secondary pressure distribution valve,
3.11... Main pressure distribution valve, 4... Pressure oil tank, 5...
・Oil supply pipe, 6... Oil drain pipe, 7... Oil collection tank, 13
．． 14...Moving coil.

Claims (1)

[Claims] A water turbine control method in which runner vanes and guide vanes are electrically controlled by a converter, characterized in that when converter control power is lost, the runner vanes are operated in the opening direction, while the guide vanes are operated in the closing direction. Method.