Control method for pumped-storage hydroelectric power plants

Abstract

The present invention makes it possible to adjust the rotation speeds of a pump-turbine runner and a generator motor rotor so as not to be largely changed when a guide vane is fully closed, by making a guide vane closure rate adjustable by means of guide vane opening at the time of disconnecting a parallel circuit breaker after break opening or breaking in a closure rate of a double-stage linear guide vane in which one breaking is provided in the middle of the closure rate from opening to a full close of the guide vane during a stop operation of a pumping stop method of a pumped-storage generation device. A transition time from a switching operation of the pumping operation into the power generation operation to the power generation operation of the pumped-storage generation device can be shortened, and a change amount of the transition time from the pumping operation to the power generation operation due to the guide vane opening at the time of disconnecting the parallel circuit breaker or the difference between the rotation speeds of the pump turbine runner and the power generation motor rotor can be made small.

Description

Technical Field

[0001] The present invention relates to control for rapidly switching from a pumping operation to a power generation operation of a constant-speed or variable-speed pumped-storage power generation device. When a switching command from the pumping operation to the power generation operation is issued and the parallel breaker is immediately disconnected and shifted to the input disconnection, in a two-stage linear guide vane closing rate with a single break in the middle of the closing rate from the stop operation guide vane opening to full close, the break opening is adjustable according to the guide vane opening at the time of disconnection of the parallel breaker, and the larger the guide vane opening at the time of disconnection, the smaller the break opening. Thus, even if the guide vane openings at the time of disconnection of the parallel breaker are greatly different, the rotational speeds of the runner of the pump turbine and the rotor of the generator motor at the time of full close of the guide vane can be adjusted so as not to change significantly in any constant-speed or variable-speed pumped-storage power generation device. The present invention relates to a rapid switching control method from a pumping operation to a power generation operation of a pumped-storage power generation device that shortens the time from when a switching command from the pumping operation to the power generation operation is issued until the rotation of the rotating body stops and power generation startup becomes possible, and reduces the amount of change according to the guide vane opening at the time of disconnection.

Background Art

[0002] The pump turbine of the pumped-storage hydroelectric power plant comprises a runner connected to a main shaft that rotates in a runner chamber sandwiched between an upper cover and a lower cover, multiple movable guide vanes provided on the outer circumference of the runner chamber to adjust the flow rate of water flowing in and out of the runner chamber, a speed ring having multiple stationary stay vanes on the outer circumference of the movable guide vanes to adjust the flow direction, an inlet valve for closing the flow path for water to flow in and out of the casing installed on the outermost circumference of the pump turbine and the runner, a lower suction pipe provided at the bottom of the runner chamber to guide the water flowing in and out of the runner chamber to the lower reservoir of the pumped-storage power plant, and a generator motor connected to the main shaft. In conventional control methods for pumped-storage power plants when stopping them during pumping operation, a linear guide vane closing rate or a two-stage linear guide vane closing rate with a fixed bend in the middle is applied to the closing rate from the open guide vane position to full closure during the stopping operation. As a result, when a switching command from pumping operation to power generation operation is issued, the parallel circuit breaker is disconnected and the system switches to input interruption. The difference in the guide vane position when the parallel circuit breaker is disconnected, or the difference in the rotational speed of the pump turbine runner and the generator motor rotor when the parallel circuit breaker is disconnected, causes a significant change in the rotational speed of the pump turbine runner and the generator motor rotor when the guide vane is fully closed. Consequently, the time from the disconnection of the parallel circuit breaker until the rotation of the pump turbine runner and the generator motor rotor stops varies greatly depending on the operating conditions at the time of disconnection. As an example of a transient phenomenon of pump input interruption in a pumped-storage hydroelectric power plant, Figure 5 shows an example of the pump input interruption transient phenomenon shown in Figure 129 of the Mechanical Engineering Handbook B, Applied Edition B5 Applied Edition 2.9.3 Transient Phenomena, published by the Japan Society of Mechanical Engineers. In the example of the pump input interruption transient phenomenon shown in Figure 5, the guide vanes are closed with a two-stage linear guide vane closure rate, which has a small bend at one point in the middle of the closure rate from the guide vane opening at the time of input interruption to full closure. Since the bend opening is constant regardless of the total head and guide vane opening at the time of input interruption and other conditions, the rotational speed of the pump turbine runner and the generator motor rotor is relatively high at 40% or more when the guide vanes are fully closed.

[0003] The rotational speed of the runner and the generator-motor rotor is reduced primarily by the sliding friction resistance caused by the runner agitating the water trapped inside the runner chamber when the guide vanes are fully closed. After a certain degree of deceleration, it takes a long time for the generator-motor to come to a complete stop due to the operation of the electric and mechanical brakes.

[0004] An example of a control method for rapidly switching a pumped-storage hydroelectric power plant from pumping operation to power generation operation is shown in Figure 5 of the Toshiba Review Vol. 58 No. 7 (2003), in the section on hydroelectric power generation technology that contributes to improving the quality of power systems. This method uses a hydraulic brake by not completely closing the guide vanes and applying a high-pressure water flow in the opposite direction of rotation to the runner. Test results with a model pump-turbine have verified that this method enables high-speed switching from pump-direction rotation to turbine-direction rotation. However, in actual pumped-storage hydroelectric power plants, the tilting and reversal of the thrust bearing's tilting pad may not always function normally against the inertial flow of lubricating oil in the oil tank in response to the rapid reversal of the direction of rotation, raising concerns that this could lead to thrust bearing damage.

[0005] As mentioned above, Figure 5 shows an example of the pump input interruption transient phenomenon, as shown in Figure 129 of the Mechanical Engineering Handbook B, Applied Edition, B5 Applied Edition 2.9.3 Transient Phenomena, published by the Japan Society of Mechanical Engineers. Figure 5 is an example of the pump input interruption transient phenomenon in a constant-speed pumped-storage hydroelectric power generation system, where the rotational speed when the guide vane opening is fully closed is approximately 44% of the rated rotational speed.

[0006] Figure 6 shows a diagram of the closed circuit for the guide vane servo motor when the input of a conventional pumped-storage hydroelectric power plant is shut off.

[0007] Symbol 1 indicates a logic function circuit. The logic function circuit 1 determines whether the guide vane servo motor stroke (hereinafter sometimes abbreviated as GVS) value is greater than or less than the GVS value when the input is cut off. It outputs 1.0 when the GVS value is greater than or equal to the GVS value when the GVS value is less than the GVS value when the GVS value is less than the GVS value when the GVS value is less than the GVS value when the input is cut off.

[0008] The symbol 2 indicates a logic AND gate, which performs a logic AND operation on the output of logic function circuit 1 and the closing command from the governor, and outputs the result.

[0009] The symbol 3 indicates a selection function circuit, which, when the output signal of the AND gate 2 is 1.0, selects and outputs the flow rate characteristics of the guide vane pressure distribution valve from GVS100% to bent GVS.

[0010] Symbol 4 indicates a logic function circuit. The logic function circuit 4 determines whether the GVS value is less than or greater than the input-cutting GVS value. It outputs 1.0 when the GVS value is less than the input-cutting GVS value, and 0.0 when the GVS value is greater than or equal to the input-cutting GVS value.

[0011] The symbol 5 indicates a logic AND unit, which performs a logic AND operation on the output of the logic function circuit 4 and the closing command from the governor, and outputs the result.

[0012] The symbol 6 indicates a selection function circuit, which, when the output signal of the AND gate 5 is 1.0, selects and outputs the flow rate characteristics for the guide vane pressure distribution valve from bent GVS to GVS0%.

[0013] The symbol 7 indicates an adder, which adds the flow rate characteristics of the guide vane pressure distribution valve for GVS100% to bent-over GVS selected by the selection function circuit 3 and the flow rate characteristics of the guide vane pressure distribution valve for bent-over GVS to GVS0% selected by the selection function circuit 6 and outputs the result.

[0014] Reference numeral 8 indicates the guide vane servo motor, and the GVS is closed according to the flow rate characteristics of the guide vane pressure distribution valve output from the adder 7.

[0015] Figure 7 shows an example of a characteristic diagram of the pumping operation range of a variable-speed pumped-storage power generator.

[0016] In Figure 7, within the variable speed pumping operating range, the rotational speed N is equal to the rated rotational speed N. OThe values ​​vary from approximately 97% to 104%, the GVS changes from 50% to a maximum of approximately 88%, and the motor input P varies from a minimum of approximately 65% ​​to 100% relative to the maximum motor input Pmax.

[0017] Figure 8 is a diagram illustrating the closing characteristics of the guide vane servo motor stroke when the input of a conventional pumped-storage hydroelectric power plant is shut off. The closing characteristics of the guide vane servo motor stroke when the input is shut off include a single bend between the shut-off GVS and GVS 0%. The closing time from the shut-off GVS to the bend GVS is 8 seconds / 100% GVS, the bend GVS is 20%, and the closing time from the bend GVS to GVS 0% is 20 seconds / 100% GVS. As shown in Figure 9 described later, the aforementioned closing characteristics are set to ensure that the rotational speed in the pumping direction when GVS 0% is reached is at least 30% in order to prevent thrust bearing damage caused by the tilt reversal of the tilting pad of the thrust bearing not functioning correctly when the rotation of the runner reverses from the pumping direction to the power generation direction during the GVS closing process.

[0018] Figure 9 shows an example of rotational speed analysis results when the guide vane servo motor stroke is fully closed in an input shutoff analysis example of a conventional pumped-storage hydroelectric power plant.

[0019] In this example of analysis results, the closing characteristics of the guide vane servo motor stroke at input cutoff shown in Figure 8 were applied, and input cutoff analysis was performed for the minimum static head and maximum static head conditions, at maximum motor input Pmax, rotational speed N=100%, and minimum motor input Pmin at GVS=50%, within the characteristic diagram of the pumping operation range of the variable speed pumped-storage power generator shown in Figure 7.

[0020] In this example of analysis results, the rotational speed analysis results when the GVS is fully closed range from approximately 41% to approximately 45% when the maximum motor input Pmax is reached, range from approximately 48.5% to approximately 50% when the rotational speed N=100%, and remain constant at approximately 63% when the minimum motor input Pmin is reached. From this, the minimum value of the rotational speed analysis results when the GVS is fully closed is approximately 41% when the maximum motor input Pmax is reached at the minimum static head, and this satisfies the requirement of at least 30% rotational speed in the pumping direction when the GVS reaches 0%, which prevents the runner rotation from reversing from the pumping direction to the power generation direction during the GVS closing process mentioned above. [Prior art documents] [Patent Documents]

[0021] [Patent Document 1] Japanese Patent Application Publication No. 4-159457 [Overview of the project] [Problems that the invention aims to solve]

[0022] Conventional methods for rapidly switching from pumping operation to power generation operation in pumped-storage power plants involve immediately disconnecting the parallel circuit breaker and switching to input interruption when a switching command from pumping operation to power generation operation is issued. However, as shown in Figures 5 and 9, in order to prevent the runner's rotation from reversing from the pumping direction to the power generation direction during the GVS closing process, a minimum pumping direction rotation speed of 30% or more is ensured when GVS 0% is reached, and in practice, at least 40% or more is ensured. However, since the rotation speed at which GVS 0% is reached is at least 40%, even with the electric brake and mechanical brake activated, it takes a long time for the rotation to stop. Power generation is started only after the complete cessation of rotation is detected, so the switch from pumping operation to power generation operation takes at least 5 minutes, and further speed increases are difficult.

[0023] As one means for solving the above situation, the control method proposed is the one proposed in Patent Document 1. This is a control method for a pump turbine when shifting from a pumping operation to a power generation operation by a switching command during the pumping operation. After disconnecting the generator motor from the system in the pumping operation state, the guide vane opening is maintained at a small opening, the rotational speed of the pump turbine in the pump direction is rapidly reduced, and while waiting for the rotational speed of the pump turbine to reverse in the power generation direction, it shifts to the power generation operation.

[0024] As a result of verifying the effect by applying the control method of the pump turbine when shifting from the pumping operation shown in Patent Document 1 to the power generation operation by a switching command, in Fig. 5 of the hydroelectric power generation technology contributing to the improvement of the quality of the power system in Toshiba Review Vol. 58 No. 7 (2003), it is shown that the total switching time can be shortened to about 1 / 2 of the conventional method as the verification result by the model test device.

[0025] However, when applying the switching from the pumping operation shown in Patent Document 1 to the power generation operation, as described above, the inclination of the tilting pad of the thrust bearing against the inertial flow of the lubricating oil in the oil sump due to the rapid reversal of the rotational direction does not always operate, and there is concern that it may lead to the occurrence of thrust bearing damage. From this, it is considered a problem that after the occurrence of thrust bearing damage, it will interfere with the operation of the pumped-storage power generation device.

Means for Solving the Problem

[0026] In order to solve the above problems, the present invention makes the one-stage buckling GVS provided between the cut-off GVS and GVS0% of the closing characteristic of the guide vane servo motor stroke at the time of input cut-off after the switching command from the pumping operation to the power generation operation adjustable based on the GVS value at the time of input cut-off, reduces the difference in the runner rotational speed of the pump turbine at the time of full closing of GVS due to the difference in the operating point at the time of input cut-off, and sets the maximum value of the runner rotational speed of the pump turbine at the time of full closing of GVS to about 10% or less of the rated rotational speed, shortening the time until rotation stops and reducing the variation in the time until rotation stops due to the difference in the operating point at the time of input cut-off.

Advantages of the Invention

[0027] According to the present invention, when a switching command from a pumping operation to a power generation operation is issued for a pumped-storage power generation device having a pump turbine equipped with movable guide vanes and a generator motor axially coupled to the pump turbine, it is possible to shorten the time until rotation stops and reduce the variation in the time until rotation stops due to differences in the operating points at the time of input interruption.

Brief Description of the Drawings

[0028] [Figure 1] FIG. 1 is a configuration diagram of a guide vane servo motor closed circuit at the time of input interruption after a switching command from a pumping operation to a power generation operation for a pumped-storage power generation device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a closed characteristic diagram of a guide vane servo motor stroke at the time of input interruption after a switching command from a pumping operation to a power generation operation for a pumped-storage power generation device according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing an example of a GVS setting implementation of a waist break in the closed characteristics of a guide vane servo motor stroke at the time of input interruption after a switching command from a pumping operation to a power generation operation for a pumped-storage power generation device according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing an example of a rotation speed analysis result at the time of full closing of a guide vane servo motor stroke in an input interruption analysis example after a switching command from a pumping operation to a power generation operation for a pumped-storage power generation device according to an embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing an example of a transient phenomenon at the time of input interruption for a pumped-storage power generation device according to a conventional example. [Figure 6] FIG. 6 is a configuration diagram of a guide vane servo motor closed circuit at the time of input interruption for a conventional pumped-storage power generation device. [Figure 7] FIG. 7 is an example of a characteristic diagram of a pumping operation range of a variable-speed pumped-storage power generation device. [Figure 8] FIG. 8 is a closed characteristic diagram of a guide vane servo motor stroke at the time of input interruption for a conventional pumped-storage power generation device. [Figure 9]Figure 9 shows an example of rotational speed analysis results when the guide vane servo motor stroke is fully closed in an input shutoff analysis example of a conventional pumped-storage hydroelectric power plant. [Modes for carrying out the invention]

[0029] The control method for a pumped-storage hydroelectric power plant according to the present invention, and more specifically, the switching control method for a pumped-storage hydroelectric power plant from pumping operation to power generation operation, will be described in detail below with reference to the drawings. However, this embodiment does not limit the present invention. [Examples]

[0030] Figure 1 is a diagram showing the configuration of the guide vane servo motor closing circuit when the input is cut off after a switching command is issued from pumping operation to power generation operation in a pumped-storage power generation system according to an embodiment of the present invention. In Figure 1, the same reference numerals as those included in Figure 6, which were used to explain the conventional example, indicate the same or corresponding components.

[0031] The configuration in Figure 1 is almost identical to the configuration of the conventional pumped-storage hydroelectric power plant shown in Figure 6. The configuration in Figure 1 is further enhanced by an additional circuit that allows for adjustment of a single stage of bending of the guide vane servo motor stroke closing characteristics between the GVS at the time of input interruption and GVS 0%, based on the GVS value at the time of input interruption as described below.

[0032] The symbol 9 indicates a negation function circuit. The negation function circuit 9 receives the ON-OFF signals of the parallel circuit breaker. The negation function circuit 9 outputs 0.0 when the parallel circuit breaker is ON and outputs 1.0 when the parallel circuit breaker is OFF.

[0033] The symbol 10 indicates a timer. The output of the negation function circuit 9 is input to timer 10. When the input is 1.0, timer 10 outputs 1.0 for the timer setting time T1. When the input is anything other than 1.0, timer 10 constantly outputs 0.0. The timer setting time T1 shall be less than or equal to the GVS closed idle time immediately after an input interruption occurs.

[0034] The symbol 11 indicates a digital-to-analog converter. The digital-to-analog converter 11 converts the digital value output from the timer 10 into an analog value and outputs it.

[0035] The symbol 12 indicates a multiplier. The multiplier 12 outputs the result of multiplying the GVS, which is the output of the guide vane servo motor 8, by the output value of the digital-to-analog converter 11. Therefore, the multiplier 12 will output the GVS value for the timer setting time T1 of the timer 10 after the parallel circuit breaker is turned OFF.

[0036] Reference numeral 13 indicates an ON-OFF signal generator. The ON-OFF signal generator 13 outputs 1.0 when the GVS value, which is the output of the guide vane servo motor 8, is several percent or more, and outputs 0.0 otherwise.

[0037] The symbol 14 indicates a multiplier. The multiplier 14 outputs the result of multiplying the output of the ON-OFF signal generator 13 by the output of the maximum value selection function circuit 15, which will be described later.

[0038] The symbol 15 indicates a maximum value selection function circuit. The maximum value selection function circuit 15 compares the output value of the multiplier 12 and the output value of the multiplier 14 and outputs the maximum value. Due to the functions of the negation function circuit 9 to the maximum value selection function circuit 15 described above, the GVS value when an input interruption occurs is output from the multiplier 12 for the timer setting time T1 of the timer 10, and the ON-OFF signal generator 13 outputs 1.0 when the GVS value is several percent or more, so when the GVS value is several percent or more, the GVS value when an input interruption occurs is self-held by the multiplier 14 and the maximum value selection function circuit 15.

[0039] Reference numeral 16 denotes a bent GVS generation function circuit. An example of the configuration of the bent GVS generation function circuit 16 is shown in Figure 3, which will be described later.

[0040] Figure 2 is a diagram illustrating the closing characteristics of the guide vane servo motor stroke when the input is cut off after a switching command from pumping operation to power generation operation in a pumped-storage power generation system according to an embodiment of the present invention. The closing characteristics of the guide vane servo motor stroke when the input is cut off include a single bend between the cutoff GVS and GVS 0%, with the cutoff GVS to the bend GVS taking 12 seconds / 100% GVS, and an embodiment of the setting of the bend GVS is shown in Figure 3, described later, where the cutoff from the bend GVS to GVS 0% takes 27 seconds / 100% GVS.

[0041] Figure 3 shows an example of the GVS setting for the bending of the guide vane servo motor stroke when the input is cut off after a switching command from pumping operation to power generation operation in a pumped-storage power generation system according to an embodiment of the present invention. In this embodiment, the bending of the GVS is constant at 50% when the GVS at cutoff is 50% or less, the bending of the GVS decreases linearly from 50% to 15% in the range of 50% or more and 90% or less when the GVS at cutoff is cutoff, and the bending of the GVS is constant at 15% when the GVS at cutoff is 90% or more. By applying the bending of the GVS setting for the guide vane servo motor stroke when the input is cut off after a switching command from pumping operation to power generation operation in Figure 3 to the closing characteristics of the guide vane servo motor stroke when the input is cut off after a switching command from pumping operation to power generation operation in the pumped-storage power generation system in Figure 2, the maximum GVS closing time when the GVS at cutoff is the maximum of 100% becomes 19.5 seconds.

[0042] Figure 4 shows an example of the rotational speed analysis results when the guide vane servo motor stroke is fully closed, in an example of input shutoff analysis after a switching command from pumping operation to power generation operation in a pumped-storage power generation system according to an embodiment of the present invention.

[0043] In this example of analysis results, the closed characteristics of the guide vane servo motor stroke when the input is cut off after the switching command from pumping operation to power generation operation shown in Figure 2, and the closed characteristics of the guide vane servo motor stroke when the input is cut off after the switching command from pumping operation to power generation operation shown in Figure 3, were applied to the bent GVS setting. Then, in the characteristic diagram of the pumping operation range of the variable speed pumped-storage power generator shown in Figure 7, the input cutoff analysis was performed for the minimum static head and maximum static head, at the maximum motor input Pmax, rotational speed N=100%, and minimum motor input Pmin with GVS=50%, similar to Figure 9.

[0044] In this example analysis, the rotational speed analysis results when the GVS is fully closed range from 7.1% to 7.4% at maximum motor input Pmax, remain constant at approximately 11% at rotational speed N=100%, and range from 7.7% to 9.8% at minimum motor input. Even if the GVS at break-off differs by more than 10%, the difference in rotational speed when the GVS is fully closed is less than 5%. Thus, the rotational speed analysis results when the GVS is fully closed in this example analysis are within the range of 7.1% to 11%, which is smaller than the range of approximately 41% to approximately 63% in the rotational speed analysis results when the GVS is fully closed in the conventional method shown in Figure 9. The maximum value is about 1 / 6th of the original value, and the range of change is also smaller at 2.1%.

[0045] Therefore, in the guide vane servo motor closing circuit when the input is cut off after a switching command from pumping operation to power generation operation of the pumped-storage power generation system configured as shown in Figure 1, by applying the bent GVS setting in the closing characteristics of the guide vane servo motor stroke when the input is cut off after a switching command from pumping operation to power generation operation shown in Figure 2 and the closing characteristics of the guide vane servo motor stroke when the input is cut off after a switching command from pumping operation to power generation operation shown in Figure 3, as described above, the maximum GVS closing time is 19.5 seconds or less, the rotational speed when the GVS is fully closed is approximately 11% or less, and it is expected that the time from the occurrence of input cutoff until rotation stops due to the operation of the electric brake and mechanical brake will be approximately 30 seconds or less.

[0046] Furthermore, even if a rapid switchover from pumping operation to power generation operation is not performed for a constant-speed or variable-speed pumped-storage power generator, by adjusting the closing rate of the closing characteristics of the guide vane servo motor stroke when the input is cut off after the switching command from pumping operation to power generation operation in Figure 2, and by adjusting the bent GVS setting in the closing characteristics of the guide vane servo motor stroke when the input is cut off after the switching command from pumping operation to power generation operation in Figure 3, and applying these to emergency stops and input cutoffs, it is possible to reduce the difference in the rotational speed of the pump turbine runner when the GVS is fully closed due to differences in the operating point when an input cutoff occurs, and to speed up restarting to pumping operation or power generation operation, including phase sync operation. [Explanation of symbols]

[0047] 1,4 Logic function circuits, 2,5 Logic AND converters, 3,6 Selection function circuits, 7 Adder, 8 Guide vane servo motor, 9 Negation function circuit, 10 Timer, 11 Digital-to-analog converter, 12,14 Multiplier, 13 ON-OFF signal generator, 15 Maximum value selection function circuit, 16 Bend-waist guide vane servo motor stroke generation function circuit.

Claims

1. When a command is issued to switch a pumping-type hydroelectric power generator, which has a pump turbine equipped with movable guide vanes and a generator motor axially coupled to the pump turbine, When the switching command from the pumping operation to the power generation operation is issued, the parallel circuit breaker is immediately disconnected and the system transitions to input interruption. In a two-stage linear guide vane closing rate with a bend in the middle of the closing rate from the guide vane opening during the stop operation to the fully closed position, the bend opening is adjustable by the guide vane opening when the parallel circuit breaker is disconnected. The larger the guide vane opening when the parallel circuit breaker is disconnected, the smaller the bend opening becomes, so that the guide vane opening when the parallel circuit breaker is disconnected is fully open. Even if the degree of rotation differs by more than 10%, the rotational speed of the pump turbine runner and the generator motor rotor when the guide vanes are fully closed can be adjusted so that the change in rotational speed does not exceed 5% of the rated rotational speed, regardless of whether the pumped-storage power generation system is constant speed or variable speed. The change in the time from when the switching command from pumping operation to power generation operation is issued until the rotation of the rotating body stops and power generation can be started due to the guide vane opening at the time of disconnection is set to less than 5% of the rated rotational speed, and the switching from pumping operation to power generation operation is performed. A method for controlling the switching of a pumped-storage power generation system from pumping operation to power generation operation.

2. When a switching command is received from the pumping operation to the power generation operation, the parallel circuit breaker is immediately disconnected after receiving the switching command signal from the pumping operation to the power generation operation. The guide vanes are closed according to the guide vane opening at the time of disconnection of the parallel circuit breaker or according to the guide vane closing determined according to the rotational speed of the runner of the pump turbine and the rotor of the generator motor at the time of disconnection. However, the inlet valve provided between the pump turbine and the iron pipe is not closed. After detecting that the rotational speed of the rotating body of the pumped-storage power generation device has stopped, the guide vanes are opened to the power generation start opening to start power generation. After the rotational speed of the rotating body of the pumped-storage power generation device reaches the parallel rotational speed of the parallel circuit breaker, the parallel circuit breaker is connected in parallel to perform the switching from the pumping operation to the power generation operation. A method for controlling the switching of a pumped-storage power generation system from pumping operation to power generation operation, as described in claim 1.

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