JPS6332166A - Operation control method for movable blade water turbine - Google Patents

Abstract

PURPOSE:To enable a movable blade water turbine to respond to load change requirement when said water turbine is subjected to controlled operation with its movable fixed, by controlling said movable blades as to be releasable depending on the amount of error between a signal for a target opening of the blades and a feed back opening signal from a hydraulic servomotor for the movable blade. CONSTITUTION:A movable blade opening setting means determines a signal for the target opening of movable blades by a guide vane opening signal 1 and a static head signal 2. When the amount of error between this target signal and the signal from a hydraulic servomotor 9 for the movable blades becomes less than the amount of error for releasing fixed movable blades, one of the opening/closing contact points 15, 16 closes, and a signal of predetermined correction value is output by one of opening/closing setting means 17, 18. This correction signal is output to a distributing valve driving circuit 7 via a contact point 19 for fixing. Due to the above construction, when any load increase is required, a distributing valve 8 and a hydraulic servomotor 9 for the movable blades can be actuated to correct the opening of movable blades 10 to respond to the load change requirement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the operation of movable blade water turbines such as Kabran water turbines, tubular water turbines, and diagonal flow water turbines having movable wings.

[Conventional technology]

In the conventional device, as described in Japanese Patent Laid-Open No. 56-148685, when the guide vane becomes unable to close.

Although consideration has been given to fully opening the movable wings and safely stopping the main engine, control stability has not been considered.

On the other hand, the present applicant has filed an application in Japanese Patent Application No. 60-025570 (unpublished) regarding a method for fixing a movable blade to improve control stability, and the method is as follows. The guide vanes and movable vanes of a movable vane hydraulic turbine have certain related characteristics in which the movable vanes are linked to the opening and closing of the guide vanes, and in their control, movable vane fixed control operation in which a fixed signal is input to the movable vanes is used. In this case, the movable blade is fixed after a certain period of time has elapsed after the control deviation (deviation) has decreased to within a predetermined movable blade fixing error amount.

In addition, when the movable blade is fixedly controlled, the guide vanes open and close according to the load, and this control deviation (deviation) is caused by the above-mentioned possible i! ! When the blade fixing error amount exceeds the II blade fixation error amount and a certain period of time has elapsed, the fixation of the movable blade is released in the case of the movable blade fixation control operation.

In this way, the rotational speed (frequency) stability is improved by being able to fix the movable blades, but since the movable blades are fixed, the output decreases when the guide vane opening is increased in response to the load signal. Therefore, it was not possible to cope with even larger loads.

In the conventional technology, when the load supply system of a movable blade hydraulic turbine is operated in a relatively unstable manner, such as by independent power transmission, the fixed movable blade control is implemented as described above in order to improve the stability of the control. ing. That is, a control method is adopted in which the load demand of the load supply system can be met simply by adjusting the opening degree of the guide vanes.

However, even if the opening degree of the guide vane is changed while the opening degree of the movable blade is fixed, the load fluctuation that can be handled is limited to a certain range due to the efficiency characteristics of hydraulic machinery. Therefore, if there is a load request that exceeds the range of load fluctuations that can be accommodated above, even if the guide vanes are changed to the maximum, they will not be able to respond to the load request and the guide vanes will run out of control (voltage drop).
This results in

In addition, in a movable blade hydroturbine, when operating in a state where the load supply system is relatively unstable, such as in isolated power transmission, the control to suppress changes in rotation speed due to load changes uses a closed loop that controls the guide vanes and a closed loop that controls the movable blades. It consists of two closed loops.

Here, compared to the former, the latter has a greater influence on control to suppress changes in rotational speed in response to changes in load. In any case, in order to make a control system composed of two closed loops stable, (1) the time constants of the two closed loops should be almost the same.

(2) The time constants of the two closed loops are extremely different.

However, making the movable blades have a fast time constant equivalent to that of the guide vanes will increase the strength.

Since this is impossible due to problems such as vibration, it is common to adopt method (2) in which the time constants of the two closed loops are extremely different (the movable blades are fixed).

On the other hand, OK! flI'yd, the efficiency characteristics of a water turbine are shown in Figure 2, where the horizontal axis shows the output and the vertical axis shows the efficiency and guide vane opening. However, even when operated in the open direction, an increase in output can only be expected within a small range due to efficiency characteristics. For example, when the movable blade opening is fixed at the R operation shown in FIG. 2, the output W operation can be obtained at the guide vane opening G at the maximum efficiency point of operation. However, the output can be increased by operating the guide vanes in the opening direction up to the G2 opening and the output W2 is the maximum output when the movable vane opening is R□. In addition, when the movable blade is constant, when the guide vane opening is B', the output curve is C' and the efficiency curve is A', and similarly, when the guide vane opening is B', the output curve is C' and the efficiency curve is A'. 'become that way. That is, in the case of a fixed control operation, if the movable blade opening degree Rr is fixed, stable operation is possible for requests up to load request W2.

If a higher load is requested, the guide vanes will run out of control.

[Problem that the invention seeks to solve]

In the control method of the above-mentioned Japanese Patent Application No. 60-025570.

Although controllability was improved by fixing the movable blades, there was no consideration given to the ability to cope with even larger loads, and there was a problem in that the output decreased when the load increased.

The present invention was made in view of the above situation, and an object of the present invention is to provide an operation control method for a movable vane hydraulic turbine that can respond to load fluctuation demands in the case of movable vane fixed control operation that can stabilize frequency control. That is.

[Means for solving problems]

The above purpose is to provide a movable blade opening setting device into which a guide vane opening signal and a static head signal are input, a movable blade control target opening signal from the movable blade opening setting device, and a hydraulic servo motor for the movable blade. The movable blade is driven through a pressure distribution valve drive circuit to which a signal is sent from an adder that receives the return opening signal of the signal and detects an error between both signals, and a pressure oil pressure distribution valve that is controlled by the signal from the pressure distribution valve drive circuit. A hydraulic servo motor for the above-mentioned movable blade that controls opening and closing.

The movable blade has a guide vane formed to operate in conjunction with certain related characteristics, and when adjusting the flow rate of the hydraulic machine and controlling the operation of the water turbine through the guide vane and the movable vane, a timer is used. between the adder and the pressure distribution valve drive circuit, which outputs a signal to fix or release the movable blade to the pressure distribution valve drive circuit when receiving a signal from the circuit in which the error is less than or greater than the fixed error amount of the movable blade; The installed fixed circuit receives the movable vane control target opening signal and the feedback opening signal from the movable vane hydraulic servo motor 1 in the case of the movable vane fixed control operation, and the error between these two signals is determined in advance. An error detection circuit that outputs a contact output to the timer circuit when the movable blade fixing error is smaller or larger than a set fixed error of the movable blade, and when the duration of the contact output from the error detection circuit reaches a preset duration. The timer circuit outputs a contact point to the fixed circuit, and receives the movable blade control target opening signal and the feedback opening signal from the movable blade hydraulic servo motor, and the error between these two signals determines the movable blade fixed setting. An error having a contact point that opens and closes a circuit that sends a correction signal from a setting device provided in the correction circuit to the pressure distribution valve drive circuit when the movable blade fixing release error amount is set to be smaller than the error amount and larger than the error amount. A detector is provided, and in the case of the movable blade fixed control operation, when the error becomes smaller than the fixed movable blade error amount, the movable blade is controlled to open in response to a load increase request. can.

[Effect]

As will be explained later in the embodiment, in the case of fixed control operation of the movable vane, the error between the movable vane control target opening signal and the return opening signal from the hydraulic servo motor 9 for the movable vane When the error range is smaller than the fixed error amount, the movable 910
will be stopped. The stability of single frequency control is therefore increased. In this state, when the error further decreases to below the movable blade fixation release error amount, the movable XIO is released from fixation in response to the load increase request and can be opened. Then, when the error becomes larger than the movable blade fixing error amount, the fixation of the movable blade 10 is released in the case of the movable blade fixing control operation. That is, when the error becomes less than the movable blade fixing error amount, the movable blade 10 is fixed, and when the error becomes less than the movable blade fixing error amount, the movable blade 10 can be unfixed, and when a load increase request is made, the movable wing 10 becomes movable. It can be opened and accommodated up to the range of wing fixed error amount.

The above-mentioned control is repeated in response to load fluctuations, and since the movable blade is fixed, stability against one frequency fluctuation is improved, and it is also possible to cope with an increase in load requirements.

〔Example〕

The method for controlling the operation of a movable vane water turbine according to the present invention will be explained below with reference to FIG. 1 using an implementation area. FIG. 1 is a block diagram of a device that implements the control method. In FIG. 0, 3 is a movable blade opening setting device into which a guide vane opening signal 1 and a static head signal 2 are sent, and the signals are sent through a fixed circuit 6. , 4 is an error detection circuit which receives signals from the movable blade opening setting device 3 and the hydraulic servo motor 9 for movable blades and sends a signal to a timer circuit 5, and the signal from the timer circuit 5 is sent to a fixed circuit 6. It has become. 7 is a pressure regulating valve l drive circuit, 8 is a pressure oil pressure regulating valve, 10 is a flexible J wing that has certain related characteristics so that it opens and closes in conjunction with the opening and closing of the guide vane when it is not fixed in particular, and 11 is an error detector. , 12 is a correction circuit, 13 is a comparator, 15 is a closing contact, 16 is an opening contact, 17 is an opening setting device, 18 is a closing setting device, and 19 is a fixing contact.

The movable blade opening setting device 3 operates a pressure distribution valve operating circuit 7 that operates a pressure distribution valve 8 using an output signal of a movable blade opening determined by a preset guide vane opening signal 1, a static head, and a movable blade opening characteristic. The movable blade 10 is driven to open and close via the pressure distribution valve 8 and the movable blade hydraulic servo motor 9. The error detection circuit 4 compares the movable vane control target opening signal output from the movable vane opening setting device 3 with the output opening signal of the movable vane hydraulic servo motor 9 in the case of movable vane fixed control operation. When the error (shift) becomes less than or exceeds a preset movable blade fixing error amount for fixing the movable blade 10, a contact output is output and sent to the timer circuit 5. Then, the time during which the contact output from the error detection circuit 4 continues is counted, and when the preset duration time is exceeded, the timer circuit 5 outputs a contact output signal that fixes or unfixes the movable blade 10. The signal is sent to circuit 6.

The error detector 11 is preset with a movable blade fixing release error amount that is smaller than the movable blade fixing error amount set in the error detection circuit 4 and larger than the error amount. It has a contact point that generates 1 PIJ when the amount is low. The structure includes a correction circuit 12 that outputs a movable blade control signal that outputs a certain control amount when the contact of the error detector 11 operates. That is, the error detector 11 uses a comparator 13 that compares the possible blade control target opening signal of the movable blade opening setting device 3 with the opening signal of the hydraulic servo motor 9 for the movable blade; If the detected error exceeds the movable blade fixing release error amount set in the error detector 11 and it is in the open direction, the open side contact 16 closes.
and a closing side contact 15 that closes in the closing direction. Further, the correction circuit 12 includes an opening direction setter 17. which outputs a constant control amount regardless of the magnitude of the error detected by the comparator 13. It has a closing direction setting device 18 and a contact point 19 that closes during movable blade fixed control.

In the above structure, the guide vane opening signal 1 and the static head difference signal 2 are taken into the movable vane opening setting device 3, and from the movable vane opening setting device 3, a constant guide vane opening, static head, and movable yt10 opening are input. Possible given by the relevant properties of! 1! lIJ Tsubasa 10
A signal for opening and closing, that is, a movable blade control target opening degree signal is output. Subsequently, the output opening signal of the movable blade opening setting device 3 and the signal for driving the movable blade 10 by the hydraulic servo motor 9 for the movable blade are branched and fed back, and an adder 14 calculates the error thereof. .

This calculated signal passes through the fixed circuit 6 and is sent to the pressure distribution valve drive circuit 7, which generates the movable blade control target opening signal and the return opening from the movable blade hydraulic servo motor 9. Since the pressure distribution valve 8 is actuated in a direction to offset the error with the signal, the hydraulic pressure is supplied to the movable blade hydraulic servo motor 9 via the pressure distribution valve 8. In addition, the reason for the above error is that it is possible! ) lJ wing 10 is connected to the opening and closing of the guide vane.
Therefore, the operation of the movable blade 10 lags behind the movable blade control target opening degree, that is, an error occurs.

On the other hand, since the opening signal of the movable blade hydraulic servo motor 9 is fed back at any time, the error between this feedback opening signal and the movable blade control target opening signal gradually decreases, and the difference between the movable blade control target opening signal and the movable blade control target opening signal gradually decreases. When the opening degree signals of the movable blade hydraulic servo motor 9 match, the signal becomes zero.

When the error becomes zero, the pressure distribution valve drive circuit 7 goes into a neutral state and returns the pressure distribution valve 8 to the neutral state, so the hydraulic pressure supplied to the movable blade hydraulic servo motor 9 by the pressure distribution valve 8 is cut off, and the movable blade The operation of the hydraulic servo motor 9 stops. At the same time, the wing 10 remains stationary. That is, the movable X (movable vane control target opening set by the opening setting device 3 and the hydraulic pressure servo motor for 9 is controlled so that the opening degrees are the same.Then, the guide vanes are constantly opening and closing in response to the load signal, so it is possible! The operation to make the error between the return opening signal and the return opening signal of the movable blade hydraulic servo motor 9 zero is to be performed at any time. The same is true for .

Next, when there is a movable wing fixing signal in the control when renumbering the movable wing fixing circuit (not shown), the operation is as follows. In addition to the fact that the movable blade 10 is controlled in conjunction with the guide vane by a signal from the movable blade opening setting device 3,
The fixed operation of the movable blades is controlled by a fixing or fixing release signal. And the movable blade opening setting device 3
The movable blade control target opening signal outputted from the movable blade control target opening signal and the feedback opening signal from the movable blade hydraulic servo motor 9 are sent to the error detection circuit 4.
and when the error between the movable blade control target opening signal and the return opening signal of the movable blade hydraulic servo motor 9 becomes smaller than a preset movable blade fixed error amount in the error detection circuit 4, the error detection circuit 4 provides a contact output to the timer circuit 5 to cause the timer to operate. Timer circuit 5
counts the duration of the contact output from the error detection circuit 4, and outputs the contact to the fixed circuit 6 when the preset duration reaches a preset duration.

When the fixed circuit 6 receives the contact output signal of the timer circuit 5, it ignores the error in the movable blade control target opening signal from the movable blade opening setting device 3 and the feedback opening signal of the movable blade hydraulic servo motor 9. The error is set to zero and output to the pressure regulating valve drive circuit 7. Therefore, since the error is assumed to be zero, the pressure regulating valve drive circuit 7. The pressure distribution valve 8 returns to the neutral state, the movable blade hydraulic servo motor 9 becomes stationary, and the movable blade 10 is fixed. In addition, in this state, the movable blade control target opening signal and the movable blade hydraulic servo motor 9
When the error with the feedback opening signal exceeds the allowable FI + blade fixed error amount, the error detection circuit 4 outputs a contact, and if this contact output continues for a predetermined period of time, the timer circuit 5 sends a signal to the fixed circuit 6. A signal to release the fixation of the movable 110 can be sent! ! The fixation of IIglO is released and it is operated in a direction in which the error between the movable blade target opening signal and the return return signal of the movable blade hydraulic servo motor 9 becomes zero. The above explanation is for the case of movable blade fixed control operation when the movable blade fixed signal is input, but when this movable blade fixed signal is released, it is possible for the error to be smaller than the fixed blade fixed error range.
Of course, the wing 10 is not fixed.

Next, in Fig. 1, a patent application filed in 1986 in which a movable blade fixing circuit was installed.
The operation of this embodiment, which is further provided with an error detector 11 and a correction circuit 12 in contrast to No. 0-25570, will be described. The comparator 13 of the error detector 11 has an error range (amount) between the movable blade control target opening signal and the return opening signal of the movable blade hydraulic servo motor 9 that is lower than the fixed blade fixed error wind. The error amount is preset as described above.

Then, when the error between the possible Δj'JA control target opening signal and the return opening signal of the movable blade hydraulic servo motor 9 becomes smaller than the fixed blade fixing release error amount, the closing side contact 15 or the opening side contact 16 is closed. The circuit remains closed during the period of time. The open and close side setters 17 and 18 are formed to output a predetermined output, and the fixed contact 19 is closed in the case of movable wing fixed control operation when there is a fixed signal of the movable wing 10. ing. Therefore, when the error between the movable blade control eye m opening degree signal and the return opening degree signal of the movable blade hydraulic servo motor 9 becomes smaller than the fixed blade fixing release error amount, it is closed.

One of the open side contacts 15 and 46 is closed, open, and the closed side setting device 17
．． 18 outputs a predetermined amount of correction signal. This signal is output to the pressure distribution valve drive circuit 7 via the fixed contact 19, which is closed when the movable blade fixed circuit is input.

When there is a load increase request, the pressure regulating valve8. The movable vane hydraulic servo motor 9 operates to correct the opening degree of the movable vane 1o.

On the other hand, as described above, the movable blade 10
Controlling the guide vanes has a greater effect than controlling the guide vanes. Further, even if the opening degree of the guide vanes is changed in a state where the opening degree of the fixed blade 10 is fixed, the load fluctuation that can be handled is limited to a certain range due to the efficiency characteristics of the hydraulic machine. However, in this example, the patent application
Similar to No. 5570, in the case of M rotation with fixed movable wing control, the fixed error of the movable wing before the error between the movable vane control target opening signal and the feedback opening signal of the hydraulic servo motor 9 for movable vane becomes zero. A certain amount is set, and when the error decreases to the fixed blade fixed error amount range, the possible tlJ5[10 is fixed. And in this state, the error can be further reduced while driving!
If it is less than +1 wing fixation release error amount, 1jJ is allowed.
The fixation of the wing 10 can be released and the movable wing fixed error amount can be increased to 8 wings 10.
It is now possible to respond to requests for increased loads by opening the That is,
For example, assuming that the movable blade fixation error amount is 50% and the movable blade fixation release error amount is 20% for the error O%, the minimum range from 20% to 50% is for movable fixed blade control operation. can respond to load increase requests.

In this way, in the operation control method of the movable blade hydraulic turbine of this embodiment, in the case of the movable blade fixed control operation, the movable blade fixation release error amount is set between the error that is smaller than the movable blade fixation error amount and the error amount is zero. If there is a request to increase the load and the error becomes less than the movable blade fixation release error amount, the movable blade will be released, and the load fluctuation request can be met up to the movable blade fixation error amount. Since it is a fixed-wing fixed control operation, the frequency can be controlled to be stable.

〔Effect of the invention〕

As described above, the operation control method for a movable vane hydraulic turbine according to the present invention has the effect of being able to respond to demands for load fluctuations in the case of movable vane fixed control operation that can stabilize frequency control.

[Brief explanation of the drawing]

Figure 1 shows the possibilities of the present invention! FIG. 2 is a block diagram of a device for carrying out the operation control method for a II-blade water turbine, and is an efficiency characteristic diagram of a J-blade water turbine. 1... Guide vane opening signal, 2... Static head signal, 3...
・Possible i blade opening setting device, 4, 11...Error detection circuit, 5
. . . Timer circuit, 6 . . Fixed circuit, 7 .・・Correction circuit,
14...Adder, 15...Closing side contact, 16...Opening side contact, 17...Opening side setting device, 18...Closing side setting device.

Claims (1)

[Claims] 1. A movable blade opening setting device into which the guide vane opening signal and static head signal are input, and a movable blade control target opening signal from the movable blade opening setting device and feedback from the movable blade hydraulic servo motor. The opening/closing control of the movable blade is performed through a pressure distribution valve drive circuit to which a signal is sent from an adder that receives the opening signal and detects the error between the two signals, and a pressure oil pressure distribution valve that is controlled by the signal from the pressure distribution valve drive circuit. a hydraulic servo motor for the movable blade, and a guide vane formed to interlock and operate the movable vane with certain related characteristics, and adjust the flow rate of the hydraulic machine via the guide vane and the movable vane. In the method for controlling the operation of a water turbine, when a signal is received from a timer circuit in which the error is less than or equal to a movable blade fixing error amount, the movable blade is fixed or a signal for unfixing is output to the pressure distribution valve drive circuit. A fixed circuit disposed between the adder and the pressure distribution valve drive circuit, and in the case of fixed control operation of the movable vane, the movable vane control target opening signal and the feedback opening signal from the hydraulic servo motor for the movable vane. an error detection circuit that outputs a contact output to the timer circuit when the error between the two signals becomes smaller or larger than a preset fixed error amount of the movable blade; and a period of time during which the contact output from the error detection circuit continues. The timer circuit outputs a contact point to the fixed circuit when a preset duration time is reached, and receives the movable blade control target opening signal and the return opening signal from the movable blade hydraulic servo motor. When the error between the two signals becomes smaller than the movable blade fixing error amount and reaches the movable blade fixing release error amount set to be larger than the error zero, a correction signal from a setting device provided in the correction circuit is sent to the pressure distribution valve drive circuit. and an error detector having a contact for opening and closing a circuit sent to the movable blade, and in the case of the movable blade fixing control operation, when the error becomes smaller than the movable blade fixing release error amount, the movable blade is activated in response to a load increase request. A method for controlling the operation of a movable blade hydraulic turbine, characterized in that the blades are controlled to be openable.