JPH10259781A - Method and device for controlling water turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely and stably continue operation by coping with incurring of a loss of a water level signal during water level regulation operation and water level difference answering operation. SOLUTION: A water level signal for the upper water tank of a hydraulic power plant is inputted through a water level holding circuit 101 and by inputting a deviation between a reference water level and a target water level, a guide vane opening command is generated by a proportional element 104 and an integrated aspect 105. A servo drive device 106 drives a guide vane servo motor to a position responding to an opening command. When a water level signal is lost due to a trouble on the water level detection side, the water level holding circuit 101 holds a preceding value and maintains control of the following opening of the guide vane, and continues water level regulation operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water turbine control device for a hydroelectric power plant having a water tank or a pond, and more particularly to a water level adjustment operation and a water level difference response using a water level signal for control calculation of an inflow water amount. Driving etc.

[0002]

2. Description of the Related Art FIG. 4 shows a schematic configuration of a hydroelectric power plant having a water tank. In a small hydroelectric power plant with a capacity of tens of thousands of kW or less, water taken from an upstream river is temporarily stored in a water tank 1 and guided to a water turbine 3 directly connected to a generator 4 through a penstock 2 to prevent overflow from the water tank 1 In order to prevent the water level from dropping excessively, the control device 8 performs a water level adjustment operation that takes the load of the water turbine so as to keep the water level constant. That is,
Based on the water level of the water tank 1 from the water level detector 7 and the opening from the opening detector 6, the servo motor 5 is controlled to adjust the opening of the guide vane or the non-abrasive blade (not shown). The load is taken so as to maintain the water level of 1 in a predetermined range.

In the water level adjustment operation, control is performed so that the amount of water Q1 flowing into the water tank 1 and the amount of water Q2 used for power generation always have the relationship of equation (1).

[0004]

Q1 = Q2 (1) Further, in a hydroelectric power station having an upper pond and a lower pond and a large head change width, a water level difference operation is performed to keep the head of both ponds within a certain range. That is, the opening of the guide vane and the runner blade is adjusted according to the head, and a load with high power generation efficiency is taken.

Japanese Patent Application Laid-Open No. 3-179171 discloses that when the runner vane and the guide vane are controlled by the converter, the runner vane is operated in the opening direction and the guide vane is operated in the closing direction when the converter power is lost, so that the turbine is safely stopped. A method for controlling a water turbine to be driven is disclosed.

[0006]

In the conventional water level adjustment operation, the water level signal of the water tank is not protected.
Since the adjustment range of the water level is set to a fraction of the water measurement range of the water tank, if the water level signal is lost, a command several times as large as a normal command will be issued.

That is, when the water level signal is lost, a several times closing signal is issued, and the guide vane servomotor 5 performs a rapid closing operation. As a result, the flow rate Q2 flowing into the turbine 3 from the guide vanes is sharply reduced, the flow rate relation of the formula (1) becomes Q1> Q2, the water level rises, the water tank 1 overflows, and from the spillway. Discarded uselessly.

When the water level signal returns to normal from this state, an open signal several times the normal level is issued, the guide vane servomotor 5 performs a rapid opening operation, and the flow rate Q2 flowing from the guide vane into the turbine 3 suddenly increases. (Q1 <Q
2) In the worst case, the water level in the water tank 1 may be excessively lowered, which may cause air to flow into the penstock 2.

The same applies to the water level difference-responsive operation. When the water level signal from the upper pond or the lower pond is lost, the servomotor is shaken by an excessive fluctuation of the water level difference signal, and an appropriate opening of the guide vane or the like is adjusted. Control becomes difficult, and efficient and stable operation adapted to the head is impaired.

In the turbine control method of the above cited example, there is no consideration for the loss of the water level signal because of the load adjustment in the normal constant speed control, and the response to the loss of the converter power supply is a vane for safely stopping the turbine. The adjustment of the opening is stopped.

SUMMARY OF THE INVENTION An object of the present invention is to provide a water turbine control method and apparatus capable of continuing operation safely and stably in response to a loss of a water level signal in a water level adjustment operation or a water level difference response operation in view of the above-mentioned problems of the prior art. Is to provide.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to provide a water level adjusting operation for controlling the amount of water flowing into a turbine so that the water storage level on the upstream side of the turbine is within a predetermined range within the water measuring range. This is achieved by holding the previous detection value when the water level detection signal is lost, and continuing the operation with the water amount fixed at the previous value.

[0013] Alternatively, in the water level difference operation for controlling the amount of water flowing into the turbine so that the difference between the water level on the upstream side and the water level on the downstream side of the water turbine is within a certain range, the upstream or downstream side is operated. This is achieved by holding the previous detection value when the water level detection signal is lost, and continuing the operation with the water amount fixed at the previous value.

A control device for a water turbine to which the method of the present invention is applied includes a water level detector for detecting a water storage level on an upstream side or a water storage level on an upstream side and a downstream side of a water turbine of a hydroelectric power plant, and a water level detector for detecting a water amount flowing into the water turbine. An inflow amount adjusting unit for adjusting, a servomotor for driving the inflow amount adjusting unit, and a control operation unit for providing a control signal to the servomotor, the control operation unit further comprising the water level detection signal or the upstream and downstream A control command output means for generating the control signal in accordance with the deviation between the water level difference signal and their target values, and a means for holding the previous value of the water level detection signal, wherein the water level detection signal is lost Preferably, a previous value is used for calculating the control signal.

The inflow amount adjusting section is a guide vane (guide vane) and / or a non-blade (runner vane), and its opening is adjusted by the servo motor.

According to the present invention, the loss of the water level signal from the water tank or the upper / lower pond is detected, and the water level applied to the water level adjustment control device or the runner vane opening control device is maintained by retaining the previous water level signal. Abrupt changes in the signal can be suppressed, the oscillation of the servomotor can be prevented, and stable operation of the power plant can be continued. In particular, in the water level adjustment operation, it is possible to prevent overflow of the water tank and air suction from the penstock,
In the water level differential operation, efficient and stable operation can be continued.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. The first embodiment is an example of application to a water level adjustment operation, and the second embodiment is an example of application to a water level difference operation.

[First Embodiment] FIG. 1 shows a configuration of a water turbine control device for performing a water level adjustment operation. The water wheel control device includes a water level adjustment control unit 10, a servo motor driving device 106, and a guide blade servo motor 107. The water level adjustment control unit 10 controls the water level detector 7 via the water level holding circuit 101.
A water level deviation signal is generated at the addition point 103a based on the water level detection signal from the controller and the reference level signal set in advance.
By using the water level deviation signal and the target water level signal, the addition point 103
At b, a water level command signal is generated. The target water level signal is obtained by a servo position signal from the guide blade servomotor 107 and an opening deviation signal generated at the addition point 3e based on a preset reference opening of the guide blade. Generate.

The water level command signal is a water level adjustment proportional element 104
And the water level adjustment integration element 105. The outputs of the water level adjustment proportional element 104 and the water level adjustment integration element 105 are added at an addition point 103c to generate a guide blade servo position command signal. The guide blade servo position command signal is added to the servo position signal at the addition point 3d, and transmitted to the guide blade servo motor driving device 106.

The guide blade servo motor driving device 106 supplies pressure oil when the servo motor 107 is of a hydraulic type and supplies drive current when the servo motor 107 is of an electric type according to a guide blade position command signal. Drive to the specified position. The guide vane servomotor 107 opens and closes a guide vane (not shown) connected by a guide ring and a link mechanism, controls the amount of water flowing into the runner, and controls the water level of the water tank 1 to be kept within a certain range.

FIG. 2 shows an embodiment of the water level holding circuit.
The water level holding circuit 101 includes a water level signal break detection circuit 121, a switching circuit 122, a first-order delay circuit 123, and an addition point 124. Normally, the switching circuit 122 is at the OFF position, and the water level detection signal of the water tank 1 is input to the + side of the addition point 124. A first-order delay circuit 1 is provided on the minus side of the addition point 124.
23 are input, and their deviation is determined by the primary delay circuit 1
23.

The first-order delay circuit 123 is constituted by an integration circuit having a time constant Ts sufficiently smaller than the time constant for controlling the water level of the water tank 1. Therefore, the current water level signal corresponding to the deviation from the addition point 124 is output to the addition point 103a after the time constant Ts.

On the other hand, when the water level detection signal of the water tank 1 is lost and the water level signal loss detection circuit 121 detects a signal loss, the switching circuit 122 is switched to the ON side. As a result,
Both inputs of the addition point 124 become the output of the primary delay circuit 123 and the deviation becomes 0, and the output of the primary delay circuit 123 holds the previous water level signal.

Further, when the water level detection signal returns from the cut-off state, the switching circuit 122 is connected again to the OFF side, and the addition point 123 outputs the deviation between the current water level and the holding water level. Also does not change suddenly. Also, 1
The change becomes gentle due to the time constant Ts of the next delay circuit 123.

According to the present embodiment, when the water level signal in the water tank is lost, the guide blades are suppressed from abruptly closing to prevent the water tank from overflowing, and when returning from the lost state, the guide blades are prevented from suddenly opening. To prevent the water level of the water tank from dropping abnormally.
As a result, effective use of water can be ensured, and factors that adversely affect water turbine main engine and water turbine control, such as suction of air into the penstock, can be eliminated, so that stable operation of the hydroelectric power plant can be continued.

[Embodiment 2] FIG. 3 shows a configuration of a water wheel control device for performing a water level difference responsive operation. When the turbine 3 is operating for power generation, water in the upper reservoir 1a flows into the turbine 3 and is stored in the lower reservoir 1b via guide vanes and runner blades. On the other hand, when the water turbine 3 is performing a pump operation for pumping water, water in the lower reservoir 1b is pumped up and stored in the upper reservoir 1a. The water level difference responsive operation is performed during the power generation operation of the water turbine 3.

The water level detection signals detected by the water level detector 7a of the upper reservoir 1a and the water level detector 7b of the lower reservoir 1b pass through an upper pond water level holding circuit 201a and a lower pond water level holding circuit 201b, respectively, and are added at an addition point 202. Generate a water level difference signal. The water level holding circuits 201a and 201b are configured similarly to the water level holding circuit 101 of the first embodiment. further,
By this water level difference signal and the target water level difference signal, the addition point 203
Generates a water level difference command signal. The target water level difference signal is generated by the target water level difference calculator 208 based on the servo position signal from the guide vane servomotor 207.

Upon receiving the water level difference command signal, the guide vane opening degree command calculator 204 calculates the water level difference adjustment proportional element and the water level difference adjustment integration element, and outputs a guide blade servo position command signal. The guide vane servo position command signal is added at point 2
At 05, the servo signal is added to the servo position signal, and the deviation is transmitted to the guide blade servo motor driving device 206. Drive device 20
Numeral 6 drives the guide blade servo motor 207 to a position where the deviation of the guide blade servo position command becomes zero. The guide vane servomotor 207 opens and closes the guide vanes connected by a guide ring and a link mechanism, controls the flow rate flowing into the runner, and controls the water level difference between the upper reservoir 101a and the lower reservoir 101b to be within a predetermined range.

According to the above configuration, the upper reservoir 1a /
When the water level detection signal from the water level detector 7a / 7b of the partial reservoir 1b is lost, the previously sampled water level signal is retained, so that the water level detection signal does not change excessively. In addition, when returning from the lost state, the change becomes gentle because the difference between the held water level detection signal and the current value is obtained.

According to the present embodiment, when the water level signal is lost and when the water level signal is restored after the loss of the water level signal, no sharp water level signal is given to the guide vane opening control unit. Therefore, the fluctuation of the servomotor is suppressed, and the stable water level difference operation of the hydroelectric power plant can be continued.

In the first and second embodiments, the example in which the opening degree of the guide blade is adjusted to adjust the flow rate of the water turbine is shown, but the present invention is not limited to this. Similarly, the opening of the runner blade may be adjusted using the water level signal, or both the guide blade and the runner blade may be adjusted. To adjust the opening of the runner blade, for example, in FIG. 1 (FIG. 3), a guide blade opening signal, which is a servo position signal of the guide blade servomotor 107 (207), is input to the runner blade setting device and the runner blade opening is adjusted. A command is generated, and a deviation between the opening command and the servo position signal from the runner blade servomotor is transmitted to the runner blade servomotor driving device.

[0032]

According to the present invention, when a water level detection signal is lost in a hydropower station performing a water level adjustment operation or a water level differential operation, the previous value is retained and the guide blades and runner blades are maintained. Since the opening is adjusted, there is an effect that the fluctuation of the servomotor due to a rapid change of the water level signal is suppressed, and the operation can be safely and stably continued.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a water turbine control device according to a first embodiment (water level adjustment operation) of the present invention.

FIG. 2 is a configuration diagram showing one embodiment of a water level holding circuit.

FIG. 3 is a configuration diagram of a water turbine control device according to a second embodiment (water level differential operation) of the present invention.

FIG. 4 is a configuration diagram schematically showing a hydroelectric power station system.

[Explanation of symbols]

1 ... water tank, 2 ... penstock, 3 ... water wheel, 4 ... generator, 5
... Servo motor, 7 ... Water level detector, 8 ... Control device, 10
... water level adjustment control unit, 101 ... water level holding circuit, 103a-
103e: adder, 104: water level proportional adjustment element, 105
... water level integration adjustment element, 106 ... servo motor drive device,
107: Guide vane servomotor, 121: Water level signal break detector, 122: Switching circuit, 123: Primary delay circuit, 20
1a: Upper pond water level holding circuit, 201b: Lower pond water level holding circuit, 202, 203: Adder, 204: Guide vane opening command calculator, 206: Servo motor driving device, 207: Guide vane servo motor.

Claims (6)

[Claims] In a water level adjustment operation for controlling an amount of water flowing into a water turbine so that a water storage level on an upstream side of the water turbine falls within a predetermined range within a water measurement range, when a water level detection signal on the upstream side is lost. A method for controlling a water turbine, comprising: maintaining a previously detected value, and continuing operation while fixing the water amount to the previous value. 2. The water level difference responsive operation for controlling an amount of water flowing into a water turbine so that a water level difference between an upstream water level and a water level on a downstream side of the water turbine is within a certain range. A method for controlling a water turbine, comprising: holding a previous detection value when a water level detection signal is lost; and continuing operation with the water amount fixed at the previous value. 3. The control method for a water wheel according to claim 1, wherein the water amount is controlled by adjusting an opening degree of a guide vane. 4. A water level detector for detecting a water level on an upstream side of a water turbine of a hydroelectric power plant or a water level on an upstream side and a downstream side.
In a control device for a water turbine having an inflow amount adjustment unit that adjusts an amount of water flowing into a water turbine, a servomotor that drives the inflow amount adjustment unit, and a control operation unit that provides a control signal to the servomotor, the control operation unit includes: A control command output means for generating the control signal in accordance with the difference between the water level detection signal or the upstream and downstream water level difference signals and their target values, and a means for holding a previous value of the water level detection signal. A control device for a water turbine, wherein when the water level detection signal is lost, a previous value is used for calculating the control signal. 5. The apparatus according to claim 4, wherein the holding means inputs a means for detecting the loss of the water level detection signal, a deviation between the current water level detection signal and its own output signal, and detects the current water level after a predetermined time. A first-order lag circuit that outputs the output signal equivalent to a signal, and a unit that normally passes the water level detection signal to the first-order lag circuit and switches the deviation to 0 when the water level detection signal is lost. A control device for a water turbine, which is provided. 6. The control device for a water turbine according to claim 4, wherein the inflow amount adjustment unit is a guide vane and / or a non-abrasive blade, and the opening is adjusted by the servomotor.