JPH06317244A - Speed control device for speed governor in water turbine generator - Google Patents

Abstract

PURPOSE:To improve reduction in speed after an excitation switch is closed even in a water turbine generator whose inertia is small by compensating an excitation loss after an excitation compensating signal is added to a speed preset value of the water turbine generator is when the generator is excited when it is started. CONSTITUTION:When a water turbine generator 3 is started, when a closing signal of an excitation switch is inputted to a single shot timer 12, a pulse signal having a constant time width is inputted to an AND circuit 13. This AND circuit 13 gives a bias signal by pulse width time to a subtracter 14 by input of the pulse signal. This subtracter 14 finds deviation between the bias signal and an output signal of an integrator 15 to integrate an output signal of the subtracter 14, and the output is given to an adder 16 as an excitation loss compensating signal attenuated by a preset time constant, and is added to a speed preset value set by a speed setting unit 1. Opening of a guide vane of a water turbine is adjusted according to a compensated signal. Thereby, influence of an excitation loss can be avoided, and time until the generator reaches rated speed can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control device for a speed governor in a water turbine generator.

[0002]

2. Description of the Related Art Generally, a speed control device for controlling a speed governor of a hydraulic turbine generator in a hydraulic power plant has a circuit configuration as shown in FIG. In FIG. 3, the speed detection signal of the water turbine generator 3 detected by the speed detector 2 is subtracted by the subtractor 4 from the speed set value set by the speed setter 1, and the speed deviation is input to the PID controller 5. To do.

In this PID controller 5, a guide vane opening command value is calculated based on the speed deviation, and this is input to the upper limiter 6 as a control output. The upper limiter 6 limits the upper limit of the control output based on the upper limit set value set by the load limit setter 7 and outputs the guide vane opening command value of the water turbine 8.

The guide vane opening command value is input to the subtractor 9, where the current guide vane opening detected by the guide vane opening detector 10 is subtracted from the guide vane opening command value to open the guide vane opening command value. The guide vane drive unit 11 is controlled by the degree deviation to open and close the guide vane of the water turbine 8.

Therefore, when the guide vanes are opened and closed, the flow rate of the turbine changes, and the speed of the turbine generator 8 is controlled. Next, the configuration of a general excitation circuit of the water turbine generator will be described with reference to FIG.

In FIG. 4, reference numeral 3 is a turbine generator, and the output end of the turbine generator 3 is connected to a system bus (not shown) through a main circuit 21. In addition, the excitation control device 23 is connected to the main circuit 21 of the water turbine generator 3 via the instrument transformer 22.
Is connected, and by this excitation control device 23, the turbine generator 3 is connected.
An excitation pulse is applied to the thyristor rectifier 24 provided in the excitation circuit to control the excitation so that the output voltage of the turbine generator 3 becomes the rated voltage.

This thyristor rectifier 24 is used in the turbine generator 3
A generator voltage is generated by applying an exciting current according to gate control by an ignition pulse to the generator exciting winding 3F from the anode power source provided by the exciting transformer 25 connected to the main circuit 21 of FIG. Let

In this case, as the operation when the generator voltage is generated, the excitation switch 26 is turned on by the synchronous speed signal (not shown), and the initial excitation switch 27 is turned on, and the storage battery 2
A generator voltage is generated by applying an exciting current to the generator exciting winding 3F by means of 8. It should be noted that the initial excitation switch 27 is opened when the generator voltage exceeds a certain level.

Now, the operation of the speed control device for the speed governor in the water turbine generator configured as described above will be described with reference to the time chart shown in FIG. Now, when the turbine generator start-up command 31 is issued, the load limit setter 7 shown in FIG. As a result, the speed of the water turbine generator 3 is zero with respect to the speed set value of the speed setter 1, and thus the guide vane opening is controlled to be open, and finally the guide vane opening is set to the load limit. Since the opening degree 32 is controlled by the setting device 7, the turbine generator 3 is controlled toward the rated speed.

When the speed of the water turbine generator 3 increases, the excitation switch 17 shown in FIG. 4 is turned on in order to generate the generator voltage. At this turning-on timing, the speed of the water turbine generator is generally 80% of the rated speed. It is thrown in when it reaches the% speed. Further, as the turbine generator 3 approaches the rated speed, the speed deviation 3 and the PID controller 5 control the guide vane opening to a no-load opening so that the turbine generator 3 reaches the rated speed.

[0011]

However, when the turbine generator is started by the speed control device of the speed governor in the conventional turbine generator as described above, as shown in the time chart of FIG. 5, the excitation switch. When 26 is turned on and the generator voltage starts to be generated, the speed of the turbine generator will decrease due to the excitation loss, and eventually the turbine generator 3 will reach the rated speed by the speed deviation and the PID controller 5. Guide vane opening is controlled.

The influence of this excitation loss is remarkable in recent small hydroelectric power plants where the inertia of the turbine is small, and after the excitation switch 26 is turned on as shown in the speed curve of the turbine generator shown in the time chart of FIG. , The speed may decrease. As a result, the turbine generator 3 is not only in a state close to low-frequency overexcitation, but also has a problem that it takes a long time to reach the rated speed.

The present invention has been made in order to solve the above problems, and its object is to improve the speed reduction due to the influence of the excitation loss after the excitation switch is turned on and to reduce the rated speed even in the turbine generator having a small inertia. It is an object of the present invention to provide a speed control device for a speed governor in a water turbine generator that can reduce the time required to reach it.

[0014]

In order to achieve the above object, the present invention obtains a guide vane opening command value of a water turbine from the deviation between a speed set value of a water turbine generator and a speed detection signal, and opens the guide vane. In the speed control device for controlling the speed of the turbine generator by adjusting the guide vane opening degree of the turbine based on the deviation between the degree command value and the guide vane opening detection signal of the turbine, the speed controller is preset when the generator is excited. Excitation loss compensating means for generating a bias signal that attenuates with a time constant as an excitation loss compensation signal is provided, and the excitation loss compensation signal output from this excitation loss compensating means is added to the speed setting value of the water turbine generator. The excitation loss of the generator is compensated.

[0015]

In the speed control device for the speed governor in the water turbine generator having such a structure, when the generator is excited at the time of starting the water turbine generator, the excitation loss compensation signal output from the excitation loss compensating means. Is added to the speed setting value of the water turbine generator, and the guide vane opening command value is calculated based on the signal compensated for the response time of the decrease in rotation speed of the water turbine generator due to excitation loss, and the guide vane opening of the water turbine is adjusted. Therefore, the decrease in speed due to the influence of the excitation loss is improved, and the time required for the generator to reach the rated speed can be shortened.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration example of a speed control device for a speed governor in a water turbine generator according to the present invention. The same parts as those in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted. Only different points will be described here. Describe.

In the present embodiment, as shown in FIG. 1, the closing signal of the excitation switch 27 (shown in FIG. 4) is given to the single-shot timer 12, and the output signal of the single-shot timer 12 is supplied together with the bias signal to the AND circuit. 13 and the output signal of the AND circuit 13 is given to the subtractor 14.

The subtractor 14 obtains a deviation between an output signal of the AND circuit 13 and an output signal obtained by integrating the output signal of the subtractor 14 by an integrator 15 and attenuates the deviation with a preset time constant. The excitation loss compensation signal is output.

The excitation loss compensation signal output from the subtractor 15 is applied to the adder 16 to add it to the speed set value set by the speed setter 1, and the output is supplied to the subtractor 4 as a speed set signal. It is what

In the speed control device for the speed governor in the water turbine generator having the above-described structure, when the water turbine generator 3 is started, the excitation switch 26 is turned on and the input signal is input to the single shot timer 12. A pulse signal having a constant time width is input to the AND circuit 13. The AND circuit 13 gives a bias signal to the subtractor 14 for the pulse width time by inputting the pulse signal. In this subtractor 14, an integrator 1 that integrates the bias signal and the output signal of the subtractor 14
The deviation from the output signal of No. 5 is obtained, and its output is given to the adder 16 as an excitation loss compensation signal that attenuates at a preset time constant, and is added to the speed set value set by the speed setter 1.

Therefore, even if the excitation loss of the water turbine causes the excitation loss of the generator, an excitation compensation signal corresponding to the loss is added to the speed setting value to control the speed governor. The target speed of the generator is apparently high,
It is possible to prevent a decrease in speed after excitation of the generator.

FIG. 2 is a time chart showing the operation of the speed control device of the speed governor in the turbine generator. Here, as compared with the conventional time chart shown in FIG. 5, the speed set value is constant (rated speed) in the related art, whereas in the present embodiment, the speed setter is set when the exciting switch 27 is turned on. Since the guide vane opening is controlled by the speed setting signal that is obtained by adding the excitation loss compensation signal that decays with the preset time constant to the setting value set in step 3, the opening of the guide vane in the closing direction is set. The time corresponding to the time constant is delayed, and the closing amount is reduced, so that the speed reduction of the water turbine generator 3 due to the influence of the excitation loss after the excitation switch is turned on can be improved.

In the above embodiment, the excitation loss compensation for the speed setting value is performed at the closing timing of the excitation switch. However, if the excitation loss compensation is performed at any speed of the turbine generator, It is possible to improve the stabilization time until the rated speed peculiar to PID is reached even with a water turbine generator that is less affected by loss.

[0024]

As described above, according to the present invention, even in a small hydroelectric power plant where the inertia of the turbine generator is small, it is possible to improve the speed reduction due to the influence of the excitation loss after the excitation switch is turned on. It is possible to provide a speed control device for a speed governor in a machine.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a speed control device for a speed governor in a water turbine generator according to the present invention.

FIG. 2 is a time chart for explaining the operation of the embodiment.

FIG. 3 is a block diagram showing a speed control device for a speed governor in a conventional turbine generator.

FIG. 4 is a connection diagram showing a configuration of a general excitation circuit of a water turbine generator.

FIG. 5 is a time chart for explaining the operation of the conventional device.

[Explanation of symbols]

1 ... Speed setter, 2 ... Speed detector, 3 ... Generator,
4 ... subtractor, 5 ... PID controller, 6 ... upper limiter, 7 ... load limiter, 8 ... water turbine, 9 ... subtractor, 10 ... guide vane opening detector, 11 ...... Guide vane drive unit, 12 ...... Single shot timer, 13
... AND circuit, 14 ... Subtractor, 15 ... Integrator, 1
6 ... Adder.

Claims (1)

[Claims] 1. A guide vane opening command value of a water turbine is obtained from a deviation between a speed setting value of a turbine generator and a speed detection signal, and a deviation between the guide vane opening command value and the guide vane opening detection signal of the turbine is obtained. In a speed control device for a speed governor in a water turbine generator that controls the speed of the water turbine generator by adjusting the guide vane opening of the water turbine on the basis of the above, damping is performed with a preset time constant when the generator is excited. Excitation loss compensation means for generating a bias signal as an excitation loss compensation signal is provided,
The excitation loss compensation signal output from the excitation loss compensating means is added to the speed set value of the water turbine generator to compensate the excitation loss of the water turbine generator. Machine speed control device.