JPH089983B2 - Variable speed hydraulic machine controller - Google Patents

Description

The present invention relates to a control device for a hydraulic machine such as a pump having a guide vane or a pump turbine, and particularly has a good followability with respect to an output fluctuation. The present invention relates to a controller for a variable speed hydraulic machine.

(Prior Art) In a hydraulic machine such as a turbine or a pump turbine installed in a hydroelectric power plant, the shaft output during turbine operation is determined by the opening of the guide vane under a constant head, so When changing the output in a hydropower plant equipped with a generator or generator motor, it is customary to control the opening and closing of the guide vanes so that the guide vane opening degree corresponds to the output target value of the generator or generator motor. is there.

FIG. 5 shows a schematic configuration of a hydroelectric power generation facility to which the present invention is applied, in which the energy of water guided from the upper pond 10 by a penstock 11 is converted into mechanical energy by a water turbine or a pump water turbine 12 to generate a generator. Alternatively, the generator motor 13 is driven, and the generated energy is supplied as electric power to an electric power system (not shown). The water after the energy is absorbed by the turbine or pump turbine 12 is discharged to the lower pond 14 as waste water.

The turbine or pump turbine 12 is provided with a guide vane (not shown), and the flow rate Q of water supplied to the turbine or pump turbine 12 via the penstock 11 is adjusted by changing the opening thereof.

FIG. 6 shows an example of a conventional output control method. The output target value P * and the generator output PG are input to the output control device 15, and the guide vane opening target value a * is output. . The guide vane control device 16 sets the guide vane opening a according to the guide vane opening target a *. The opening of the guide vane 17 is controlled by the opening a of the guide vane, and the flow rate flowing into the water turbine or the pump water turbine 12 is adjusted to adjust the shaft output Pt thereof.

On the other hand, a variable speed control device 18 such as a cycloconverter for controlling the rotation speed is connected to the generator or the generator motor 13, and the rotation speed is set by the rotation speed setting device 19 according to the output target value P *. The target value N * is controlled.

The generator output PG is the release of inertial energy of the rotating part due to changes in the shaft output Pt and the rotation speed N of the turbine or pump turbine 12,
It is a value determined by the sum of absorption.

FIG. 7 shows an example of output control when the output is changed in this way. In this figure, the horizontal axis represents time T, and the vertical axis represents generator output PG, guide vane opening a, and effective head H of the turbine.
e, changes in the turbine flow rate Q, rotation speed N, and rotation speed target value N * are shown. The solid line in the figure of the generator output PG shows the actual generator output PG, and the broken line shows the output target value. P * is shown. As can be seen from FIG. 7, immediately after the point A at which the generator output started to change, the actual output PG greatly deviates from the output target value P *, and the target is to reduce the output. However, there is a phenomenon that it rises and then falls. This phenomenon is caused by a water hammer in the penstock 11 connected to the turbine or pump turbine.

That is, in the hydroelectric power generation device having the above-described configuration, when the flow rate of water is changed by changing the opening of the guide vane, the water hammer action of the penstock 11 causes the water turbine installed at its end or The water pressure at the inlet of the pump turbine 12 fluctuates. Assuming that the inlet pressure of the water turbine or pump turbine 12 at this time is H, this inlet pressure H can be expressed as follows from the basic equation of water hammer.

H = C · dQ / dt + Ho (1) where the flow rate Q is the flow rate of water flowing through the penstock 11, Ho is the inlet water pressure of the turbine or pump turbine 12 before the flow rate Q changes, and C is the penstock. 11 is a negative constant determined by the length, cross-sectional area, water density, etc.

That is, the water pressure H depends on the rate of change dQ / dt of the flow rate Q of water.
When the flow rate Q decreases, the water pressure H becomes higher than the water pressure Ho before the change.

Therefore, considering the characteristics of FIG. 7, when the guide vane opening a is started to be closed in an attempt to reduce the generator output PG,
The flow rate Q decreases, and as a result, a water hammer phenomenon occurs in the penstock mentioned above, and the inlet pressure of the turbine increases, so that the effective head He of the turbine also increases.

Since the shaft output Pt of the water turbine is almost proportional to the product of the flow rate Q of water and the effective head He of the water turbine, if the increase in the effective head He of the water turbine due to the water hammer action is large, the shaft output of the turbine temporarily increases. To do. That is, the absolute value of the temporal change rate of the water flow rate Q | d
If Q / dt / | is large, the above problems will occur.

As described above, the flow rate Q of water is adjusted by the guide vane opening degree a. That is, the flow rate change rate dQ / dt changes according to the guide vane opening change rate da / dt. Therefore, when the opening change rate da / dt of the guide vane opening a is large, dQ / dt becomes large, and the rise in inlet water pressure due to the water hammer phenomenon becomes large. As a result, a phenomenon occurs in which the shaft output Pt of the water turbine temporarily changes in the opposite direction to the output target value P *.

On the other hand, in the rotation speed setting device 19 (Fig. 6), the output target value P
In order to realize the most efficient operation of the water turbine based on *, the rotational speed target value N * is output. This optimum rotation speed N *
There is a relation between the output target value P * and the output target value P * as shown in FIG. That is, the rotational speed target value N * is large where the output target value P * is large, and N * is small where the output target value P * is small.

As shown in FIG. 7, when the down direction command is issued to the output target value P *, the rotation speed target value N * also becomes the down direction command. The rotation speed N is controlled by the rotation speed control device 18 to which the rotation speed target value N * is input so as to approach the rotation speed target value N *. As a result, the rotation speed N is decelerated as shown in FIG.

As described above, as the output target value P * decreases, the water hammer output of the hydraulic iron pipe causes the output Pt of the water turbine to temporarily increase, and the rotational speed N is controlled in the decreasing direction. Energy will be released. Therefore, although the output target value P * is decreasing, the generator output
The decrease that PG once rises in reverse appears.

As a clue for solving such a problem, for example, as shown in Japanese Patent Publication No. 52-40392, there is one provided with a compensation circuit for the instability of the hydraulic turbine control system which occurs when the guide vanes are opened and closed.

This technique improves control characteristics by providing a compensation circuit with a small time constant of the governor, but because the turbine rotational speed is controlled under a constant value,
The actual output deviates transiently from the output target value when the output fluctuates, and the above-mentioned problems have not been solved before.

(Problems to be Solved by the Invention) As described above, according to the conventional technique, the control characteristic is determined by whether the output of the generator or the generator motor responds inversely once or the actual output deviates in response to the request from the power system. Has not improved, which has been a problem in the operation of grid power.

(Object of the Invention) The present invention has been made to solve the above-mentioned drawbacks in the prior art, and has a variable speed hydraulic power system capable of providing a stable output by providing good followability with respect to an output request from the system. An object is to provide a control device for a machine.

[Structure of Invention]

(Means for Solving Problems) A variable speed hydraulic machine according to the present invention includes a hydraulic machine such as a water turbine or a pump turbine provided with a guide vane for adjusting the amount of water, and a variable speed generator directly connected to the hydraulic machine or A variable speed generator motor (hereinafter referred to as a variable speed generator motor, etc.) is provided, and the actual output of the variable speed generator motor, etc. is compared with the output target signal, and the guide vanes are opened based on the deviation. Of the guide vane based on the opening target signal of the guide vane from the output control device and a guide vane control device that gives an opening correction signal to the guide vane. The rotation speed correction control circuit that differentiates the speed signal and multiplies the differential signal by a negative gain to generate a speed correction signal for the variable speed generator motor, and this rotation speed correction control circuit. And a rotation speed control device that adds the rotation speed target signal generated based on the output target signal to the speed correction signal, calculates the added signal and gives it to the variable speed generator-motor, etc., and corrects the rotation speed. In addition to the above, the increase / decrease of the shaft output with respect to the water hammer of the penstock caused by the opening / closing command of the guide vane from the rotation speed control device is absorbed and released by the inertia of the rotating body of the hydraulic machine.

Further, in order to solve the above-mentioned problems, a control device for a variable speed hydraulic machine according to the present invention is a hydraulic machine such as a hydraulic turbine or a pump hydraulic turbine including a guide vane for adjusting the amount of water,
A variable speed generator or a variable speed generator motor (hereinafter referred to as a variable speed generator motor, etc.) directly connected to this hydraulic machine is provided, and the actual output and output target signal of the variable speed generator motor, etc. An output control device that produces an opening target signal for the guide vanes based on the deviation and a guide vane control that gives an opening correction signal to the guide vanes based on the opening target signal for the guide vanes from this output control device. A rotation speed correction for differentiating the opening target signal of the guide vane branched and output from the output control device and multiplying the differential signal by a negative gain to generate a speed correction signal for a variable speed generator-motor, etc. The rotation speed target signal generated based on the output target signal is added to the control circuit and the speed correction signal from this rotation speed correction control circuit, and the added signal is calculated. It is provided with a rotation speed control device that gives the speed generator motor etc. and corrects its rotation speed, and also increases or decreases the shaft output for a water hammer of a hydraulic iron pipe that occurs when there is an opening and closing command from the rotation speed control device to the guide vane. , The inertia of the rotating body of a hydraulic machine causes absorption and release.

(Operation) In the control device for a variable speed hydraulic machine according to the invention configured as described above, the opening of the guide vane is corrected according to the deviation between the output target and the actual output, while the guide vane opening signal is differentiated. Then, the differential signal is multiplied by a negative gain to create a speed correction signal, the speed correction signal produced is added to the rotation speed that matches the output target, and the added signal is calculated to calculate the variable speed generator or In addition to being used as the target rotation speed of the variable speed generator-motor, the output fluctuation caused by the drop fluctuation caused by the water hammer action of the penstock by opening and closing the guide vanes is absorbed and released by the inertia of the water wheel rotating body.

Therefore, the variable-speed generator or the variable-speed generator-motor can follow the output target satisfactorily without deviating from the output target, and the output can be stably provided.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of an output control system to which the control method according to the present invention is applied, in which water guided by a penstock 11 passes through a guide vane 17 and passes through a turbine or a pump turbine 12.
To rotate. The shaft output Pt of the turbine or the pump turbine generated by this is converted into the electric output Pt by the variable speed generator 13.
Converted to G.

When the output target value P * is given, the output control device 15 compares it with the actual generator output PG to derive the guide vane opening target value a *. This value is input to the guide vane control device 16 to output the guide vane opening a.

On the other hand, the optimum rotation speed setting device 19 outputs a rotation speed target value N * corresponding to the output target value P * to the rotation speed control device 18. The opening of the guide vane is detected by the guide vane opening detection device 20 and input to the rotation speed correction control circuit 21.

Here, if a lowering command is given as the output target value P *, the output control device 15 determines that the guide vane opening target value a
Issue a command to reduce *. This closes the guide vanes.

As a result, the amount of water in the penstock 11 decreases, a water hammer phenomenon occurs, and the effective head on the turbine or pump turbine increases, so the shaft output Pt of the turbine or pump turbine increases.

At this time, the guide vane opening degree detection device 20 detects the guide vane opening degree a and sends it to the rotation speed correction control circuit 21.
This rotation speed correction control circuit calculates the rate of change or the differential value of the guide vane opening a.

Next, the operation of the above-described embodiment of the present invention will be described with reference to FIGS. 1 and 2. The definitions of lines and symbols are the same as those in the above figures.

FIG. 2 shows the case where the output target value P * is in the decreasing direction.
In this case, since the guide vanes are closed, the rate of change or the differential value takes a negative value. Therefore, the rotation speed correction control circuit 21 multiplies the change rate or the differential value by a negative gain to obtain the speed correction value Nc. In this case, a value obtained by adding the speed correction value Nc to the rotation speed target value N * is sent to the rotation speed control device 18.

The rotation speed control device 18 controls the actual rotation speed to a rotation speed higher than the rotation speed target value N * by a speed correction value Nc. When the rotation speed is increased, a part of the water wheel shaft output Pt is absorbed as inertia energy of the rotating part. Therefore, the rotational speed is increased so that the surplus energy (water turbine shaft output) shown in FIG. 7 in which the generator output PG increases inversely with respect to the output target value P * is absorbed as inertial energy of the rotating portion. If so, the generator PG will not once rise in response to the command to decrease the output target value P *, and as shown in FIG. 2, the generator output PG follows the output target value P *. Performance is improved, and stable output control is possible.

FIG. 3 shows another embodiment of the present invention. This embodiment is different from the above-described embodiment in that the guide vane opening a
Instead, the guide vane opening a * is sent to the rotation speed correction control circuit 21, the rate of change or the differential value of the guide vane opening a * is calculated, and this value is multiplied by a negative gain to obtain a speed correction value Nc. Is added to the rotational speed target value N * and the rotational speed N is controlled by the rotational speed control device 18.

In this embodiment, when the output target value P * decreases,
Since the guide vane opening a * is decreased, the rate of change or the differential value of a * becomes negative. On the other hand, since the guide vane opening a * also closes as a * decreases, the penstock 11
The effective head increases due to the water hammer phenomenon caused by the decrease in the flow rate inside the pump, and the shaft output Pt of the turbine or pump turbine increases. However, the rate of change or the differential value of the guide vane opening target value a * was multiplied by a negative gain. By increasing the rotation speed by correcting the rotation speed target value N * with the speed correction value Nc, the increase in the shaft output Pt of the water turbine or the pump water turbine described above is absorbed as the rotation energy (inertial energy) of the rotating portion.

According to this method, the output target value P * shown in FIG.
There is no longer a phenomenon that the generator output PG swings in the opposite direction once the power down command is issued, and the generator output PG with respect to the output target value P *
The followability of is improved.

In each of the above-described embodiments, the case where the output target value P * decreases is described. However, the output control can be performed in the same manner even when a command to increase the output target value P * is issued. That is, when the output target value P * increases, the output control device 15 commands the target value a * in the direction of opening the guide vanes.
When this opening command a * is input, the guide vane controller 16 opens the guide vanes 17.

At this time, since the flow rate increases in the penstock, a water hammer phenomenon occurs and the effective head decreases. Due to this reduction in effective head, the shaft output of the turbine or pump turbine is reduced even though the outlet increase command is issued.

On the other hand, the rate of change or the differential value of the guide vane opening a or the guide vane opening target value a * (in this case, it is positive)
A negative gain Nc (in this case, a negative gain) is added to the target rotational speed N * to control the rotational speed N to reduce the shaft output of the turbine or pump turbine. This is compensated for by releasing inertial energy from the rotating part. As a result, the followability of the generator output PG with respect to the output target value P * is improved and stable output control can be performed.

In addition, as shown in FIG. 4, when the above embodiment is applied to a power plant where a plurality of hydraulic turbines or pump turbines 12a, 12b are operated by branching a single penstock 11 When the number of operating units that are simultaneously controlled to the output target value P * is large, the flow rate change dQ / dt is large, so the change in the effective head due to the water hammer phenomenon of the penstock is large, and the target output P * is also changed When the number of operating units to be controlled is small, the flow rate change dQ / dt is small, so in consideration of the small change in the effective head due to the water hammer phenomenon, the rotation speed correction control device 21
Even if the number of operating vehicles changes, the output target value P * can be changed by increasing the absolute value of the negative gain multiplied by the change rate of the guide vane opening when the number of operating vehicles is large and decreasing it when the number of operating vehicles is small. The output control can be performed so that the followability of the generator output PG with respect to is suitable.

〔The invention's effect〕

As described above, according to the present invention, output control during power generation operation is extremely stable, and hydraulic power generation equipment can be controlled with good followability.

[Brief description of drawings]

FIG. 1 is a control block diagram for realizing a method for operating a variable speed hydraulic machine according to the present invention, FIG. 2 is a graph showing its operation, and FIG. 3 is a control block diagram showing another embodiment of the present invention. FIG. 4 is a system diagram of a power plant having a branch water channel showing still another embodiment of the present invention, FIG. 5 is a schematic diagram of a conventional hydropower plant, and FIG. 6 is a control block of a conventional hydropower plant. Figures 7, 7 and 8 are graphs showing the operation. 10 …… Kamiike, 11 …… Pneumatic pipe, 12 …… Water turbine or pump turbine, 13 …… Variable speed generator motor, 14 …… Shimoike, 15 …… Output control device, 16 …… Guide vane control device, 17… … Guide vanes, 18 …… Rotation speed control device, 19 …… Rotation speed setting device, 20 …… Guide vane opening detection device, 21 …… Rotation speed control circuit.

Claims (2)

[Claims] 1. A hydraulic machine such as a hydraulic turbine or a pump hydraulic turbine having a guide vane for adjusting the amount of water, and a variable speed generator or a variable speed generator-motor directly connected to the hydraulic machine (hereinafter referred to as variable speed generator-motor etc.). With and
The output control device that matches the actual output of the variable speed generator / motor and the output target signal, and creates the guide vane opening target signal based on the deviation, and the guide vane opening target signal from this output control device A guide vane control device that gives an opening correction signal to the guide vane based on the above is provided, while the opening signal detected from the guide vane is differentiated, and the differential signal is multiplied by a negative gain to correct the speed of the variable speed generator motor, etc. A rotation speed correction control circuit that generates a signal, and the rotation speed target signal generated based on the output target signal is added to the speed correction signal from this rotation speed correction control circuit, and the added signal is calculated to generate variable speed power. Water that is generated when there is an opening / closing command from the rotation speed control device to the guide vane while it is provided with a rotation speed control device that gives it to the electric motor etc. The increase or decrease of shaft power to water hammer iron pipe, the variable Tsutomu Hayami machine controller, characterized in that allowed to absorb discharged to the inertia of the rotating body hydraulic machine. 2. A hydraulic machine such as a hydraulic turbine or a pump hydraulic turbine provided with a guide vane for adjusting the amount of water, and a variable speed generator or a variable speed generator-motor directly connected to the hydraulic machine (hereinafter referred to as variable speed generator-motor etc.). With and
The output control device that matches the actual output of the variable speed generator / motor and the output target signal, and creates the guide vane opening target signal based on the deviation, and the guide vane opening target signal from this output control device On the other hand, a guide vane control device for giving an opening correction signal to the guide vane based on the above is provided. A rotation speed correction control circuit that generates a speed correction signal for a variable speed generator-motor, etc., and the rotation speed target signal generated based on the output target signal is added to the speed correction signal from this rotation speed correction control circuit, and the addition is performed. It is equipped with a rotation speed control device that calculates a signal and gives it to a variable speed generator-motor, etc., and corrects its rotation speed. The increase or decrease of shaft power to water hammer penstock that occurs when a decree variable Tsutomu Hayami machine controller, characterized in that allowed to absorb discharged to the inertia of the rotating body hydraulic machine.