JPH06178597A - Speed governor control constant switcher for water-wheel generator - Google Patents

Abstract

PURPOSE:To automatically switch a control constant of a speed governor of a water-wheel generator from the conformity side to the stable side or vice versa according to a change in state of the system. CONSTITUTION:A speed governor control constant switch of a water-wheel generator detects the actual output of the water-wheel in its actual output detecting section and converts the output into an actual output electric signal 6 of a constant range and then outputs it. In an equivalent output converting section 4, the switch detects an opening of a guide vane and converts the output equivalent to the one to be generated when the water-wheel is operated at the detected opening in a steady-state into an equivalent output electric signal 7 and then outputs it. The actual output signal 6 and the equivalent output signal 7 are compared with each other in a comparing section 5. A control constant switching section 10 switches a control constant of the speed governor according to the magnitude of a deviation signal that is a result of the comparison between the signals 6 and 7. By this method, the state of operation of the water-wheel is properly checked and the control constant of the speed governor is exactly switched.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, in a hydraulic power plant, a speed governor used in a turbine generator is configured so that the opening of a guide vane (needle in a Pelton turbine) of a turbine responds to a change in system frequency. Adjusting the frequency, allowing stable operation of the turbine generator speed, and rapidly closing the guide vanes in the event of a load shedding, etc., to prevent an excessive increase in the turbine generator speed. It must have a preventive function. In other words, it is required to have stability during steady operation and responsiveness during transition. In this way, the speed governor is required to have opposite two-sidedness, and therefore it is usually handled by switching the control constant of the speed governor to the stable side or the quick response side by a signal from the outside. ing.

As a conventional example of this control constant switching system, the one shown in FIG. 4 is conventionally known. That is,
As shown in the sequence of FIG. 4, the control constant switching circuit 10 is used by using the conditions of the relay contacts 8a and 8b of the generator parallel breaker and the limit switch contact 9 that operates when the guide vanes reach a certain opening. The control constant of the speed governor is switched by giving a switching command to the speed controller, and the control constant of the speed governor is switched by giving this to the speed governor arithmetic circuit 11. In FIG. 4, 12a and 12b are holding relays.

In this conventional method, when load cutoff occurs due to the opening of the generator parallel breaker, the control constant of the governor is on the immediate response side until the limit switch contact 9 is switched. The guide vane is closed to prevent excessive rotation of the turbine generator speed, and after that, the limit switch contact 9 is switched and the control constant becomes stable, so that the rotation speed of the turbine generator after the load is cut off is reduced. It is possible to obtain stability and stability of operation of the guide vanes.
In normal parallel operation, the turbine generator's effect of suppressing fluctuations in rotation speed due to system frequency stabilizes the rotation speed of the turbine and the operation of the guide vane even if the guide vane responds rapidly. Was there.

However, an abnormality has occurred in the power transmission system and the far end is cut off, or the operation is carried out with the load of the system carried by only one turbine generator (hereinafter referred to as an independent operation). In this case, that is, when the generator is still in parallel and an abnormality occurs in the power transmission system, and the effect of suppressing generator speed fluctuations due to the system frequency cannot be obtained, the control constant is always switched to the immediate response side. In some cases, the operation of the guide vanes and the rotation speed of the generator could not be stabilized.

Therefore, in order to avoid this, the sequence shown in FIG. 5 may be used, but this system is controlled by the condition of the limit switch contact 9 which operates when the guide vane reaches a certain opening. The constants are switched. In this case, even if the turbine generators are not in parallel, if the guide vane has a certain opening, usually at or above the no-load opening of the turbine generator, the limit switch will switch to the ready side and the guide vane will open. Below that, it will switch to the stable side.

According to this method, when the load is cut off by opening the generator parallel circuit breaker, as in the above-mentioned method,
First, the guide vane responds rapidly, and eventually the rotation speed of the turbine and the operation of the guide vane are stable, but it is not possible to operate alone or at the guide vane opening above the switching point of the limit switch. When the load operation is performed in an area where the transmission system capacity is relatively small compared to the capacity, the control vane is always switched to the response side, so the opening of the guide vane and the rotational speed of the turbine generator are not stable forever. The situation sometimes occurred.

[0008]

As described above, in the conventional speed governor control constant switching device for a hydraulic turbine generator, in the case of the system shown in FIG. In the case of the operation that occurs and the effect of suppressing the fluctuation of the generator speed due to the system frequency cannot be obtained, the control constant is always switched to the immediate side, and the operation of the guide vane and the generator speed are always changed. There is a problem that it may not be possible to stabilize, and in the case of the method shown in FIG. 5, in the independent operation at the guide vane opening above the switching point of the limit switch and the generator capacity. On the other hand, when performing load operation in an area where the transmission system capacity is relatively small, the control constant is constantly switched to the immediate side, so the opening of the guide vane and the rotational speed of the turbine are stable forever. Situation that had there has been a problem that may occur.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to appropriately determine the operating condition of the water turbine generator and to appropriately switch the control constant of the speed governor. An object of the present invention is to provide a speed governor control constant switching device for a water turbine generator.

[0010]

A speed governor control constant switching device for a hydraulic turbine generator according to the present invention detects an actual output of the hydraulic turbine generator and converts it into an actual output electric signal of a constant range. And an output corresponding to that generated when the opening of the guide vane is detected and the turbine generator is operated in a steady state at the opening, and an output equivalent to that in the same range as the actual output detector is output. A corresponding output detecting unit for converting into a signal, a comparing unit for comparing the actual output signal from these actual output detecting units and the corresponding output signal from the corresponding output detecting unit, and depending on the magnitude of the deviation signal from this comparing unit. And a control constant switching unit for switching the control constant of the speed governor.

[0011]

In the speed governor control constant switching device for a hydraulic turbine generator according to the present invention, the actual output detection unit detects the actual output of the hydraulic turbine generator, converts it into an actual output electric signal of a certain range, and outputs it. The output converter detects the opening of the guide vane and outputs the output equivalent to that generated when the turbine generator operates in a steady state at that opening, with the equivalent output electric power in the same range as the actual output detector. Convert to a signal and output. Then, the comparison unit compares these actual output signals with the corresponding output signals, and the control constant switching unit switches the control constants of the speed governor according to the magnitude of the deviation signal as the comparison result. , The operating condition of the turbine generator is properly judged and the control constant of the speed governor is switched appropriately.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

Generally, the actual output A generated by the turbine generator and the output corresponding to that generated when the turbine generator operates in a steady state at the opening of the guide vane at that time, that is, the equivalent output B When and are compared according to the driving state, the results are as follows. FIG. 1 shows the relationship between the actual output A and the equivalent output B when operating in a steady state. In this case,
The actual output A and the corresponding output B match.

However, when the load is cut off or an abnormality occurs in the power transmission system and the generator operates independently, the actual output changes as shown in FIG. In other words, when an abnormality occurs in the power transmission system and suddenly the generator becomes independent operation, or when the frequency of the power transmission system suddenly changes, the opening of the guide vane becomes constant due to the inertia energy of the rotating body of the turbine generator. However, the actual output changes as shown in FIG. The greater the degree of frequency change in the system, the greater the change in the actual output, and the greater the deviation from the equivalent output.
That is, when a disturbance is applied to the load side of the turbine generator, even if the output of the turbine to the turbine generator is constant, the generator output fluctuates.

Therefore, according to the present invention, it is determined from the change of such a phenomenon that the actual output and the corresponding output are in a transient state when there is a deviation, and at that time, the response of the guide vanes is made to be fast. If the control constant of the governor is switched to the immediate response side, and then the actual output and the equivalent output match due to the operation of the guide vane, it is considered that the transient state has been passed, so the control constant of the governor is stabilized. By controlling so that when the generator operates independently, a large change in the transmission system causes the guide vanes to respond quickly and reduce the frequency change in the system.After that, the guide vanes and turbine generator rotation It is possible to perform stable operation in terms of numbers. In load shedding, the guide vanes are first closed rapidly, regardless of the difference in conditions such as opening the generator parallel circuit breaker or the far-end shut-off due to a transmission system accident. After that, the control constants of the speed governor are automatically switched to the stable side so that stable operation of both the guide vane and the turbine generator rotation can be performed. In this way, the control constants of the governor are switched between the quick response side and the stable side at a timely timing in accordance with the change in the system, thereby responding promptly to the change in the system,
In addition, it enables stable operation under normal conditions.

FIG. 3 is a block diagram showing an embodiment of a speed governor control constant switching device for a water turbine generator. The apparatus of this embodiment includes a generator output detector 1 for detecting an actual output of a water turbine generator, and an actual output converter 2 for converting a detection signal of the generator output detector 1 into an actual output electric signal of a constant range. Equipped with
Further, the guide vane opening detector 3 for detecting the opening of the guide vane, and the opening detection signal of the opening detector 3 are output corresponding to those generated when the turbine generator is operated in a steady state. Equivalent output converter 4 for converting into an equivalent output signal indicating
Is equipped with. Furthermore, the actual output signal 6 from the actual output converter 2 and the equivalent output signal 7 from the equivalent output converter 4
Is provided with an output comparator 5 for comparing the control constant set in the speed governor control constant switching circuit 10 from the stable side to the immediate response side based on the comparison result. The control constant is given to the speed governor arithmetic circuit 11.

Next, the operation of the speed governor control constant switching device of the turbine generator having the above configuration will be described.

The actual output of the turbine generator is detected by the generator output detector 1 and given to the actual output converter 2, where it is converted into an actual output signal 6 of a certain range and the output comparator 5
Entered in. Further, the guide vane opening detector 3 outputs a detection signal of the guide vane opening, and the equivalent output converter 4
Is converted into a corresponding output signal 7 of a certain range, which indicates an output corresponding to that generated when the turbine generator is operated in a steady state, and is input to the output comparator 5.

The output comparator 5 compares the magnitudes of the generator actual output signal 6 and the equivalent output signal 7, and when the actual output signal 6 and the equivalent output signal 7 match, switches to the stable side control constant, When the actual output signal 6 and the corresponding output signal 7 do not match, a signal for switching to the immediate response side control constant is output to the control constant switching circuit 10 of the speed governor arithmetic circuit 11.

Therefore, the governor control constant switching circuit 10
Upon receiving the switching signal from the output comparator 5, if the response side is the response side, the response side control constant is selected and given to the speed governor arithmetic circuit 11. If it is the stable side, the stable side control constant is selected and the speed governor calculation is performed. It is given to the circuit 11.

In this way, in the speed governor control constant switching device of the hydraulic turbine generator of this embodiment, when there is a deviation between the actual output and the equivalent output, it is judged to be in a transient state, and at that time, If the control constant of the governor is switched to the immediate response side to speed up the response of the guide vane, then if the actual output and the equivalent output match due to the operation of the guide vane, it is considered that a transient state has been passed and It is possible to control the control constant so that it returns to the stable side.In addition, for load cutoff, regardless of the difference in conditions such as when the generator parallel circuit breaker is opened or the far-end cutoff due to a transmission system accident, first The guide vane is closed to prevent excessive rotation of the turbine generator, and then the control constants of the speed governor are automatically switched to enable stable operation of both the guide vane and turbine generator rotation. By changing the control constants of the governor between the quick response side and the stable side in a timely manner according to changes in the system, it is possible to quickly respond to changes in the system and perform stable operation in normal conditions. Like

In the actual operation of the turbine generator,
Since the relationship between the opening degree of the guide vanes and the equivalent output in the hydroelectric power station changes depending on the head difference of the flowing water given to the water turbine, it is preferable to correct the head output signal to the equivalent output converter 4 if necessary. . Further, in the control constant switching by the output comparator 5, it is preferable that the coincidence between the generator actual output signal 6 and the corresponding output signal 7 and the detection of the disagreement point can be arbitrarily adjusted.

[0023]

As described above, according to the present invention, when a deviation occurs between the actual output of the generator and the equivalent output, the control constant of the speed governor is automatically switched to the immediate response side. By controlling, it is possible to detect that a deviation has occurred between the actual output and the equivalent output, and switch to the control constant on the immediate response side, even when the generator is in independent operation or when the load is cut off. It is possible to suppress the frequency change of the system to a small level and prevent an excessive increase in the rotational speed of the turbine generator.

Further, since the control constant of the governor is normally operated on the stable side, the guide vanes do not make an excessive response even in an area where the transmission system capacity is relatively small, and the transmission system frequency Stabilization can be measured.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the actual output of a turbine generator in a steady state and the equivalent output obtained from the opening of a guide vane.

FIG. 2 is a graph showing changes in the actual output of the water turbine generator in a transient state during islanding and load shedding.

FIG. 3 is a circuit block diagram of an embodiment of the present invention.

FIG. 4 is a sequence diagram of a conventional example.

FIG. 5 is a sequence diagram of another conventional example.

[Explanation of symbols]

 1 Generator output detector 2 Actual output converter 3 Guide vane opening detector 4 Equivalent output converter 5 Output comparator 6 Actual output signal 7 Equivalent output signal 10 Control constant switching circuit 11 Speed governor arithmetic circuit

Claims (1)

[Claims] 1. An actual output detection unit for detecting an actual output of a water turbine generator and converting it into an electric signal of an actual output of a constant range, and an opening of a guide vane is detected. An output corresponding to that generated when the machine is operated in a steady state, an equivalent output detection unit for converting into an equivalent output electric signal in the same range as the actual output detection unit, and an actual output signal from the actual output detection unit And a corresponding output signal from the corresponding output detection unit, and a control constant switching unit for switching the control constant of the speed governor according to the magnitude of the deviation signal from the comparison unit. Generator governor control constant switching device.