JPH045828B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides an electric speed regulator that adjusts the opening degree of a guide vane according to a frequency change ΔF in order to adjust the rotational speed of a water turbine that drives a generator. The present invention relates to an electric speed governor that does not exert unnecessary effects on equipment attached to a water turbine, particularly when the load suddenly decreases when the load is interrupted.

[Technical background of the invention and its problems] Conventionally, an electric speed governor has been designed to electrically detect a frequency change ΔF and drive an electric servo motor when the frequency change ΔF exceeds a preset amount. Therefore, there are some models in which the opening degree of the guide vane can be adjusted. In this type of electric speed governor, the guide vanes close rapidly when the load is cut off or when the load suddenly decreases, which increases the water pressure fluctuation rate and not only causes high pressure to act on the penstock, etc. The weak pin (which connects the guide vane and electric servo motor and protects the electric servo motor by breaking itself when excessive pressure is applied to the guide vane) is damaged due to excessive confinement of the guide vane, etc., and the water turbine is not included. This was causing unnecessary effects on the equipment.

[Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and its purpose is to prevent unnecessary effects on water turbine auxiliary equipment even when the load is interrupted or when the load suddenly decreases. An object of the present invention is to provide an electric speed governor that can prevent such problems.

[Summary of the Invention] The electric speed governor according to the present invention includes a first detection means for detecting the opening degree of the guide vane, a second detection means for detecting a change in the output frequency of the generator, and a first detection means for detecting the opening degree of the guide vane. , a control means for applying a control output to a servo motor that drives the guide vane according to the output of the second detection means; and a control means that outputs from the first and second detection means exceed a predetermined value. The present invention is characterized in that the guide vane is provided with means for suppressing the output of the control means, and the operation of the guide vane is delayed immediately before fully closing when the load is cut off or when the load suddenly decreases.

[Embodiment of the Invention] Hereinafter, an electric speed governor according to the present invention will be described according to an embodiment shown in FIG.

In FIG. 1, 1 is a frequency change (ΔF) detector that outputs the deviation between the reference frequency and the generator frequency. This ΔF detector 1 is set so that the output reaches its maximum value when the frequency change ΔF becomes +10% or more. A comparator 2 detects a sudden change in the frequency change ΔF output by comparing the ΔF detector 1 with a preset amount. 3 is a relay that closes its contact 3A based on the output of the comparator 2.

A potentiometer 4 is attached near the guide vane and outputs a signal corresponding to the opening degree of the guide vane. Reference numeral 5 denotes a comparator that detects a guide vane opening of 10% or less by comparing the output of the potentiometer 4 with a preset amount. A relay 6 opens and closes contacts 6A and 6B according to the output of the comparator 5.

Reference numeral 7 denotes a governor control circuit which takes in the outputs of the ΔF detector 1 and the potentiometer 4, and gives a control signal to a servo motor for driving a guide vane, which will be described later, according to the outputs. 8 is an amplifier that amplifies the output of the governor control circuit 7 to a predetermined signal level.
Reference numeral 9 denotes an output level switch constructed by connecting contacts 3A, 6A, 6B and a variable resistor 10 as shown, and the output of this switch is given as a driver output to the driver of the servo motor that drives the guide vane.

Next, the operation of this embodiment configured as described above will be explained. That is, when a sudden load decrease occurs, the rotational speed of the generator increases rapidly, and the output of the ΔF detector 1 suddenly changes. Here, since ΔF detector 1 is set so that the output becomes the maximum value when ΔF exceeds +10%, comparator 2
detects when the output of the ΔF detector 1 reaches the maximum value and closes the contact 3A of the output level switching circuit 9 via the relay 3.

As a result, the voltage of the current driver output divided by the variable resistor 10 was input to the contact 3A, but since the contact 6B is not closed, the signal level of the driver output does not change.

At this time, the ΔF output is at its maximum, so
The driver output from the governor control circuit 7 reaches its maximum value, and the guide vane closes due to the rapid operation of the servo motor.

On the other hand, when the guide vane becomes less than 10% open due to the operation of the servo motor, the comparator 5 operates, and the relay 6 opens the contact 6A and closes the contact 6B. In this case, the aforementioned comparator 2
In addition to the closing condition of the contact 3A due to the operation of , the output of the comparator 5 opens the contact 6A and closes the contact 6B, so that the final output is switched to the voltage divided by the variable resistor 10.

Therefore, the stroke operation of the servo motor is switched to a slower one, and the operation of the guide vane is delayed before it is fully closed, so that high pressure is not applied to the penstock and unnecessary stress is added to the weak point pin. Not at all.

Here, the operating speed of the stroke can be set and changed using the variable resistor 10. FIG. 2 shows the stroke characteristics of the above servo motor. In Figure 2, A is the stroke of the servo motor 10
% position, and this speed switching position A is
It can be set to any position by the comparator 5.

In addition to the embodiments described above, the present invention is limited to, for example, as long as the output level switch 9 suppresses the output of the governor control circuit 7 according to the outputs of the ΔF detector 1 and the potentiometer 4. It's not a thing. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, according to the present invention, the first detection means detects the opening degree of the guide vane, the second detection means detects the output frequency change of the generator,
A control means that provides a control output to a servo motor that drives the guide vane according to the outputs of the first and second detection means, and a control means that outputs of the first and second detection means are set to predetermined values. and means for suppressing the output of the control means when the output exceeds
It is possible to provide an electric speed governor that can delay the operation of the guide vanes just before they are fully closed even when the load is interrupted or the load suddenly decreases, thereby preventing unnecessary action from being exerted on the equipment attached to the water turbine. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an electric speed governor according to the present invention, and FIG. 2 is a diagram for explaining the operation of the embodiment. 1... Frequency change (ΔF) detector, 2, 5...
... Comparator, 3, 6 ... Relay, 4 ... Potentiometer, 7 ... Governor control circuit, 8 ... Amplifier, 9 ... Output level switching circuit, 10 ... Variable resistor.

Claims (1)

[Claims] 1 A first detection means that detects the opening degree of the guide vane, and a second detection means that detects the output frequency change of the generator.
a detecting means; a control means for providing a control output corresponding to the outputs of the first and second detecting means to a servo motor that drives the guide vane;
An electric speed governor comprising means for suppressing the output of the control means when the output of the second detection means exceeds a predetermined value.