JPH0442549B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for controlling the operation of a multi-stage hydraulic machine.
In particular, the steady state of a multistage hydraulic machine in which the flow paths of each stage from the highest pressure stage to the lowest pressure stage are connected by return passages, and the highest pressure stage and the lowest pressure stage are equipped with movable guide vanes. This invention relates to a load adjustment control method during operation.

[Technical background and problems of the invention]

The operation of a multi-stage hydraulic machine, in which each stage from the highest pressure stage to the lowest pressure stage is equipped with a runner and each stage is connected by a return passage, is controlled by guide vanes installed around the runners of each stage. This is done by adjusting the opening degree and controlling the water flow condition of each step. However, it is extremely difficult to provide a movable guide vane outside the runner of each step and to connect the opening/closing operation mechanism to the movable guide vane of each step due to structural constraints.

For this reason, in some conventional multi-stage hydraulic machines, only fixed vanes are installed on the outside of the runners of each stage, and operation is controlled by opening and closing an inlet valve installed at the inlet of the hydraulic machine. Since adjustment is performed only by the inlet valve, there has been a problem in that the hydraulic performance of the multistage hydraulic machine is significantly degraded at small and large flow rates far from the design point.

As a solution to the problems of the operation control method using the inlet valve control method, a movable guide vane that can adjust the opening of the water port is installed only in the highest pressure stage or the lowest pressure stage, and this movable guide vane adjusts the water flow rate. A multi-stage hydraulic machine that performs adjustment is considered, but it still has problems such as vibration, noise, and cavitation when operating at a small flow rate.

Therefore, we developed a multi-stage hydraulic machine that is structurally reasonable and reasonable, and has relatively high hydraulic performance.It is equipped with a movable guide vane in the highest pressure stage and the lowest pressure stage that can adjust the opening of the water port. Hydraulic machines can be considered.

In this way, a multi-stage hydraulic machine with movable guide vanes in the highest pressure stage and the lowest pressure stage has a more complex flow path shape than a single stage hydraulic machine, and has two sets of movable guide vanes. Therefore, it is necessary to accurately adjust the opening degree of each movable guide vane during load adjustment control during steady-state operation, which is particularly important. If this opening adjustment is not performed reliably, the ratio of the head that acts on the entire multi-stage hydraulic machine to the runners of each stage (head share) will be different and uneven, and each stage will differ from the reference point. Since the system falls into an isolated and unstable hydraulic characteristic region, it causes a decrease in hydraulic performance, an excessive increase in water pressure in the low-pressure side section, and an operational state that is likely to be accompanied by vibration, noise, cavitation, etc., which poses problems.

However, there are many technologically unexplored fields in the multistage hydraulic machine itself, which is equipped with movable guide vanes in the highest pressure stage and the lowest pressure stage, and it is necessary to perform load adjustment control during steady operation, which is particularly important for operation. A simple and accurate operation control method for this case has not yet been proposed.

[Purpose of the invention]

Therefore, an object of the present invention is to securely control the opening of each movable guide vane in the highest pressure stage and lowest pressure stage using target load and actual load signals when performing load adjustment control during steady operation. An object of the present invention is to provide a method for controlling the operation of a multi-stage hydraulic machine, which enables accurate load adjustment control under such operating conditions.

[Summary of the invention]

In order to achieve the above object, the present invention provides a runner for each stage from the highest pressure stage to the lowest pressure stage, and each stage is connected by a return passage, and the highest pressure stage and the lowest pressure stage are connected to each other by a return passage. In a multi-stage hydraulic machine equipped with a movable guide bay for adjusting the water port opening on the inlet side of each stage of the pressure stage; when performing adjustment control to the target load during steady power generation operation, the highest pressure stage or the lowest pressure stage The movable guide vane on either step of the section is a guide corresponding to a target load that satisfies a predetermined relative relationship between the load and the guide vane opening so that high performance operation can be performed under a given operating water level. While setting the vane opening degree, the opening degree of the movable guide vane in the other stepped section is controlled so that the relative difference or relative ratio between the actual load and the target load at the same movable guide vane falls within a specified range. It is characterized by

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for controlling the operation of a multi-stage hydraulic machine according to the present invention will be described below with reference to the drawings, taking a flange type two-stage pump turbine as an example.

On the shaft of the single water turbine main shaft 1, there is a high pressure stage runner 2.
and a low pressure stage runner 3 are fixedly spaced apart from each other in the axial direction. The high pressure stage runner 2 is surrounded by an upper cover 4 and a lower cover 5, while the low pressure stage runner 3 is surrounded by an upper cover 6 and a lower cover 7, forming a high pressure stage runner chamber 8 and a low pressure stage runner chamber 9. There is. The high-pressure stage runner chamber 8 and the low-pressure stage runner chamber 9 are connected by a return passage 10, and on the passage are provided return vanes 11 and a low-pressure stage movable guide vane 12 that can change the opening degree of the water port. Further, a spiral casing 13 is disposed outside the high pressure stage runner chamber 8, and the spiral casing 13 and the high pressure stage runner chamber 8 are connected to the spiral casing 13.
The inlet of the whirlpool chamber 14 is connected to a penstock via an inlet valve (not shown), and the penstock communicates with the upper pond. Furthermore, a high-pressure stage movable guide vane 15 is provided on the outside of the high-pressure stage runner 2 and can change the opening degree of the water port. A suction pipe 16 is connected to the low-pressure stage runner chamber 9, and its downstream side is connected to a waterway, which communicates with the lower pond.

Next, an embodiment will be described in which the operation control method according to the present invention is applied to the above-mentioned two-stage pump turbine.

FIGS. 2 and 3 show an embodiment in which load adjustment control is performed under steady-state operation.

First, the water level detection device 17 is used to detect the water level difference Hst between the water level of the upper pond and the water level of the lower pond, and the signal thereof is input to the arithmetic and control device 18. Data indicating the relationship between the load P and the guide vane opening degree a is stored in advance in the arithmetic and control device 18 via the data input device 19. The relationship between the load P and the guide vane opening a is determined by a hydraulic performance model test using the water level difference Hst as a parameter, as shown in Fig. 4, and the target load P _p
is set, the guide vane opening degree a _p that realizes the target load is specified.
The target load P _p is set by applying an input signal from the target load input device 20 to the arithmetic and control device 18 . Further, an output signal representing the guide vane opening degree a _p determined by the arithmetic and control device 18 is given to the high pressure stage guide vane control device 21, which sets the opening degree of the high pressure stage movable guide vane 15 to a _p .

As described above, as the guide vane opening degree is controlled to correspond to the operating target load of the high pressure stage movable guide vane 15, the guide vane opening degrees in the high pressure stage runner 2 and the low pressure stage runner 3 become relatively different. Therefore, the head sharing ratio changes and the actual load also changes.

On the other hand, in order to control the opening degree of the low-pressure stage movable guide vane 12, the load detection device 22 is used to detect the actual load, and the detection signal is input to the arithmetic and control device 18. As shown in Fig. 5, this arithmetic and control device stores the results of experiments that have been previously determined to determine the relationship between the relative difference P-P _p between the actual load P and the target load P _p with respect to the target load P _p . ing. Furthermore, as shown in FIG. 6, the results of the relationship of the relative ratio P/P _p between the actual load P and the target load P _p with respect to the target load P _p are previously obtained through experiments are stored. Therefore, the relative load difference P−P _p or the relative load ratio P/
The opening degree of the low-pressure stage movable guide vane 12 may be controlled so that P _p falls within the specified rectangular range indicated by hatching in FIGS. 5 and 6. The target load is set by applying an input signal from the target load input device 20 to the arithmetic and control device 18. Furthermore, the result calculated by the calculation control device 18 is calculated by the movable guide vane control device 2 of the low pressure stage.
3, and the opening degree of the low pressure stage movable guide vane 12 is set to a.

In other words, when the relative load difference or relative load ratio exceeds a specified range that is preset to achieve a head sharing state that enables high-performance operation at each stage, the low-pressure stage movable guide vane 12 is moved in the closing direction. Conversely, if the relative load difference or relative load ratio is below the specified range, the low pressure stage movable guide vane 12 may be operated in the opening direction.

In this way, a control command for the guide vane opening corresponding to the target load is transmitted to the high-pressure stage movable guide vane 15 to control the opening, while at the same time controlling the relative difference or relative ratio between the actual load and the target load. By transmitting a command to the low pressure stage movable guide vane 12 and controlling the opening degree, an operating state at a predetermined target load can be realized.

In the above embodiment, the control command for the guide vane opening corresponding to the target load is sent to the high pressure stage movable guide vane 15.
However, conversely, the above control command may be given to the low pressure stage movable guide vane 12.

That is, the operating water level detected by the water level detection device 17, for example Hsti, and the target load input device 20
A signal representing the target load Po from is input to the arithmetic and control unit 18, and the guide vane opening degree a _p corresponding to the target load Po is determined using the water level difference as a parameter.
is determined, and a control signal corresponding to the guide vane opening a _p is transmitted from the arithmetic and control device 18 to the guide vane control device 21 to control the opening of the low pressure stage movable guide vane 12.

On the other hand, as for the high-pressure stage movable guide vane 15, as shown in FIG. (See Figures 5 and 6), move the high pressure stage movable guide vane 15 in the closing direction,
Conversely, if it is below the specified range, a control command for operating in the opening direction is output from the arithmetic and control device 18 to the guide vane control device 23 to control the opening degree of the movable guide vane 15.

Next, other embodiments of the present invention will be described with reference to FIGS. 7 to 11.

In the above-mentioned invention, the relative difference or relative ratio between the actual load and the target load is controlled to be maintained within a specified range, whereas in this invention, the actual opening of the movable guide vane to be controlled and the target load are controlled. Control is performed so that the relative difference or relative ratio with the equivalent guide vane opening falls within a specified range.

That is, FIG. 7 and FIG. 8 show an embodiment in which load adjustment control is performed under steady operation. First, the water level between the water level of the upper pond and the water level of the lower pond is detected using the water level detection device 17. The difference Hst is detected and the signal is input to the arithmetic and control unit 18. Data representing the relationship between the load P and the guide vane opening degree a is stored in the arithmetic and control device 18 via the data input device 19. The load P and guide vane opening degree a are determined by a hydraulic performance model test using the water level difference Hst as a parameter, as shown in Fig. 4. Once the target load Po is set, Guide vane opening to achieve target load Po
a _p is becoming identified. The target load is set by applying an input signal from the target load input device 20 to the arithmetic and control device 18. Further, an output signal representing the guide vane opening degree a _p determined by the arithmetic and control unit 18 is given to the high pressure stage guide vane control device 21, which sets the opening degree of the high pressure stage movable guide vane 15 to a _p .

As the guide vane opening degree of the high pressure stage movable guide vane 15 is controlled to correspond to the operating target load, the guide vane opening degrees of the high pressure stage runner 2 and the low pressure stage runner 3 become relatively different, so the head is shared. The ratio also changes and the actual flow rate also changes.

On the other hand, in order to control the opening degree of the low pressure stage movable guide vane 12, as shown in FIG. The detection signal is fed back and input to the arithmetic and control unit 18. This arithmetic and control unit 18 has a ninth
As shown in Fig. 1 and Fig. 10, the relative difference a-a p and the relative ratio a/ _a between the actual opening a which allows stable operation due to hydraulic characteristics and the guide vane opening a _p corresponding to the target load. The experimental results of _p are stored.
Therefore, in order to perform stable operation due to hydraulic characteristics, the actual opening a and the target load guide vane opening a _p
The opening degree of the low-pressure stage movable guide vane 12 is adjusted so that the relative difference a-a _p and the relative ratio a/a _p fall within the rectangular prescribed area indicated by hatching in FIGS. 9 and 10. Just control it. The target load is set by applying an input signal from the target load input device 20 to the arithmetic and control device 18.
Furthermore, the result calculated by the calculation control device 18 is output to the movable guide vane control device 22 of the low pressure stage,
The opening degree of the low pressure stage movable guide vane 12 is set to a.

That is, when the opening difference or opening ratio exceeds the specified range for high performance operation at each stage, the low pressure stage movable guide vane 12 is moved in the closing direction, and vice versa. If the power ratio is below the specified range, the low pressure stage movable guide vane 12
All you have to do is operate them in the opening direction.

In this way, the control command for the guide vane opening corresponding to the target load is transmitted to the high pressure stage movable guide vane 15 to control its opening, while the actual opening and the guide corresponding to the target load are transmitted to the low pressure stage movable guide vane 15. It is possible to control the opening of the low pressure stage movable guide vane by transmitting a control command for the opening difference or the opening ratio between the vane opening and the operating state at a predetermined target load.

In the above embodiment, a control command for the guide vane opening corresponding to the target load was given to the high pressure stage movable guide vane 15, but conversely, the above control command was given to the low pressure stage movable guide vane 12. You can also give it to someone.

That is, the operating water level detected by the water level detection device 17, for example Hsti, and the target load input device 20
A signal representing the target load Po from is input to the arithmetic and control unit 18, and the guide vane opening degree a _p corresponding to the target load Po is determined using the water level difference as a parameter.
is determined, and a control signal corresponding to the guide vane opening a _p is transmitted from the arithmetic and control device 18 to the guide vane control device 21 to control the opening of the low pressure stage movable guide vane 12.

On the other hand, as for the high-pressure stage movable guide vane 15, as shown in FIG. If the value exceeds the specified range set in advance to enable high-performance operation, the highly variable guide vane will be moved in the closing direction, and conversely, if it is below the specified range, it will be moved in the open direction. Control commands to be operated are sent from the arithmetic and control device 18 to the guide vane control device 2.
3 to control the opening of the movable guide vane 15.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when performing load adjustment control during steady operation,
The movable guide vane on either the high-pressure stage movable guide vane or the low-pressure stage movable guide vane is set to the guide vane opening for the target load, and the movable guide vane on the other stage is set to the actual load and target load. Since the opening degree is controlled so that the relative difference or relative ratio of By selecting the combination of movable guide vane opening degrees that is optimal in terms of hydraulic performance, operation with the best hydraulic performance is possible. As a result, it is possible to always perform high-performance operation by avoiding unstable operating conditions accompanied by vibration, noise, cavitation, abnormal water pressure fluctuations, etc., which are problems when performing load adjustment control during steady-state operation. .

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of a Francis type two-stage pump turbine to which the present invention is applied, Figs. 2 and 3 are block diagrams showing the configuration of the operation control of the movable guide vane during steady operation, and Fig. 4 is Figure 5 is a diagram showing the relationship between target load and guide vane opening. Figure 5 is a diagram showing the specified range of relative difference between actual load and target load in the steady operating range. Figure 6 is a diagram showing the specified range of the relative difference between the actual load and target load in the steady operating range. A diagram showing the specified range of the relative ratio between the actual load and the target load, Figures 7 and 8 are block diagrams showing the configuration of operation control during steady operation according to another invention, and Figure 9 shows the configuration of the operation control during steady operation. FIG. 10 is a diagram showing the relationship between the target load and the guide vane opening ratio in the steady operation range. 2...High pressure stage runner, 3...Low pressure stage runner, 1
0...Return passage, 12...Low pressure stage movable guide vane, 15...High pressure stage movable guide vane, 17...
Water level detection device, 18... Arithmetic control device, 19...
Data input device, 20...Target load input device, 2
1, 23...Guide vane control device, 22...Load detection device, 24...Guide vane opening detection device.

Claims (1)

[Claims] 1 Each step from the highest pressure step to the lowest pressure step is equipped with a runner, and each step is connected by a return passage.
In a multi-stage hydraulic machine that is provided with a movable guide vane that adjusts the water port opening on the inlet side of each of the highest pressure stage section and the lowest pressure stage section, when performing adjustment control to a target load during steady power generation operation. , the general movable guide vane of either the highest pressure stage section or the lowest pressure stage section has a predetermined relationship between the load and the guide vane opening so that high performance operation can be performed under a given operating water level. In addition to setting the guide vane opening corresponding to the target load to satisfy the relationship,
Operation of a multi-stage hydraulic machine characterized in that the opening degree of the movable guide vane of the other stepped part is controlled so that the relative difference or relative ratio between the actual load and the target load in the movable guide vane of the same part is within a specified range. Control method.