Control method for a hydroelectric power generation system and hydroelectric power generation system

Abstract

This allows for the consumption of surplus power during power outages while keeping system size and costs down. [Solution] A control method for a hydroelectric power generation system that supplies power to a power grid, comprising a water turbine arranged in a water channel, a generator driven by the water turbine, a power converter that converts AC power generated by the generator into DC power, a power generation controller that controls the power generation of the generator, and auxiliary equipment that uses power, wherein the power generation controller starts to reduce the power generation torque of the generator when a power outage occurs in the power grid, and consumes the surplus power, which is the power generated after the power outage, by increasing the output of the auxiliary equipment, decreasing the efficiency of the generator, or decreasing the efficiency of the power converter.

Description

Technical Field

[0001] The present invention relates to a control method for a hydroelectric power generation system and a hydroelectric power generation system.

Background Art

[0002] By adding a hydroelectric power generation system to existing facilities, it is possible to supply the power of the facilities or supply (reverse power flow) the generated power to the electrical system for power sales. For example, a hydroelectric power generation system is known in which a waterwheel is added to a flow path provided with a pressure reducing mechanism of a water supply facility, and a generator is driven using the rotation of the waterwheel. In such a hydroelectric power generation system, for example, when a power outage occurs on the electrical system side, it becomes impossible to consume the generated power, so it is necessary to stop the power generation by the generator. However, since it takes time for the operation of a valve that adjusts the flow rate of water passing through the waterwheel or a valve that switches to a flow path bypassing the waterwheel, surplus power is generated before the power generation stops. Also, although the generated power can be reduced by reducing the generation torque of the generator, the flow rate of water increases as the generation torque decreases. Therefore, in the case of a water supply facility, the function of the pressure reducing mechanism is impaired. There is also a method of providing a resistor for consuming surplus power, but the resistor is an unnecessary facility except during a power outage, and since heat is generated when consuming surplus power, countermeasures in terms of safety are required, so there are problems in terms of size and cost.

[0003] Patent Document 1 discloses a hydroelectric power generation system for solving the above problems. This system comprises a first pipe on which a water turbine is located, a second pipe that branches off from the first pipe upstream of the water turbine and rejoins the first pipe downstream of the water turbine, and a secondary bypass pipe that branches off from the first pipe upstream of the water turbine and downstream of the branching point with the second pipe, and rejoins the first pipe downstream of the water turbine and upstream of the rejoining point with the second pipe. An electric valve is provided in the secondary bypass pipe. In the event of a power outage, the system is controlled to turn off the generator torque, and when the resulting increase in pump rotation speed exceeds a threshold, the valve in the secondary bypass pipe is opened to allow water to flow into the secondary bypass pipe. By turning off the generator torque and allowing water to flow into the secondary bypass pipe in this way, power generation can be stopped quickly. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-058025 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, even with the hydroelectric power generation system described in the above-mentioned literature, it is unavoidable that surplus power will be generated between the time the generator torque is turned off and the power generation stops. Therefore, resistors are needed to consume this surplus power, and there is room for improvement in terms of size and cost.

[0006] Therefore, the present invention aims to enable the consumption of surplus electricity during power outages in hydroelectric power generation systems while suppressing increases in system size and cost. [Means for solving the problem]

[0007] According to one aspect of the present invention, a control method is provided for a hydroelectric power generation system that supplies power to a power grid, comprising a water turbine arranged in a water channel, a generator driven by the water turbine, a power converter that converts AC power generated by the generator into DC power, a power generation controller that controls the power generation of the generator, and auxiliary equipment that uses the power. In this method, when a power outage occurs in the power grid, the power generation controller starts to reduce the power generation torque of the generator and consumes the surplus power, which is the power generated after the power outage, by increasing the output of the auxiliary equipment, decreasing the efficiency of the generator, or decreasing the efficiency of the power converter. [Effects of the Invention]

[0008] According to the above embodiment, in a hydroelectric power generation system, it becomes possible to consume surplus electricity during a power outage while suppressing an increase in system size and cost. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram showing the schematic configuration of a hydroelectric power generation system. [Figure 2] Figures 2(a) to (c) are graphs illustrating how surplus electricity is consumed. [Figure 3] Figure 3 shows an example of a time chart when surplus power suppression operation is performed. [Figure 4] Figure 4 shows an example of a rotor efficiency map. [Figure 5] Figure 5 is a graph illustrating other examples of how surplus electricity can be consumed. [Figure 6] Figure 6 is a portion of a flowchart showing the control routine for consuming surplus power. [Figure 7] Figure 7 is another part of the flowchart showing the control routine for surplus power consumption. [Figure 8] Figure 8 is yet another part of the flowchart showing the control routine for consuming surplus power. [Figure 9]Figure 9 is an example of a time chart when the control routines shown in Figures 6 to 8 are executed. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings.

[0011] [System Configuration] Figure 1 is a block diagram showing the schematic configuration of the hydroelectric power generation system according to this embodiment. The hydroelectric power generation system of this embodiment is a so-called small-scale hydroelectric power generation system that is added to existing facilities. In this embodiment, a hydroelectric power generation system added to the pressure reduction mechanism of a water supply facility is described, but it is not limited to this. For example, it may be added to the water line of a factory equipped with a water receiving line, a drainage line, or a cooling water line.

[0012] The hydroelectric power generation system comprises a generator 1, a power converter 2, a controller 3, a turbine 4, a first channel 5, a second channel 7, and auxiliary equipment 9. The first channel 5 is provided with a first valve 6, and the second channel 7 is provided with a second valve 8.

[0013] The turbine 4 is installed in the first channel 5 and rotates using the energy of the water flowing through the first channel 5. The rotation of the turbine 4 is transmitted to the generator 1, which generates electricity. In Figure 1, the first valve 6 is located downstream of the turbine 4, but this positional relationship may be reversed.

[0014] The generator 1 is a three-phase AC motor, and the generated power is converted to DC power by the power converter 2. The power conditioner (hereinafter also called PCS) 11 controls the reverse flow of the converted generated power to the power grid 12 and the supply to equipment within the facility (hereinafter also called self-consumption). If a resistive load 13 is provided, the power supply to the resistive load 13 is also controlled.

[0015] The second channel 7 branches off from the portion of the first channel 5 upstream of the turbine 4 and merges with the portion of the first channel 5 downstream of the first valve 6.

[0016] Auxiliary machine 9 is, for example, a cooling device for generator 1 and power converter 2. More specifically, it is a radiator fan for increasing the cooling efficiency of the radiator included in the liquid-cooled cooling device. This radiator fan is electric and is driven by PWM control.

[0017] Note that as generator 1, power converter 2, and auxiliary machine 9, a drive motor, an inverter, and a cooling device removed from a used electric vehicle may be used.

[0018] Note that a battery (which may be a resistive load) 10 may be further provided, and a part of the power may be supplied to battery 10. This enables leveling of the power generation amount and ensuring of a backup power source in an emergency.

[0019] [Control during power outage] Next, the control of the hydroelectric power generation system executed by controller 3 when a power outage occurs will be described.

[0020] In a hydroelectric power generation system that reverse-flows generated power to the power grid as shown in FIG. 1, when a power outage occurs in power grid 12 and the reverse flow stops, since the generated power is no longer consumed, it is necessary to stop the power generation of generator 1. However, power generation also occurs between the time when the generation torque of generator 1 is turned off to stop the power generation and the time when the power generation actually stops, resulting in so-called surplus power, which needs to be consumed.

[0021] Furthermore, turning off the power generation torque increases the rotational speed of the turbine 4, but it is necessary to ensure that it does not exceed the allowable rotational speed. In the configuration shown in Figure 1, the increase in the rotational speed of the turbine 4 can be suppressed by closing the first valve 6 and opening the second valve 8. However, considering the responsiveness of the first valve 6 and second valve 8 used in the water flow path of a water supply facility, and the effort required for opening and closing them, the generation of excess power is unavoidable. Moreover, in the case of a pressure reducing mechanism for a water supply facility, it is necessary to keep the secondary side pressure constant, and it is difficult to achieve both maintaining the secondary side pressure, suppressing excess power, and suppressing the rotational speed of the turbine 4 by simply controlling the opening and closing of the first valve 6 and second valve 8.

[0022] Therefore, in this embodiment, surplus power is consumed in the manner described below.

[0023] Figures 2(a) to 2(c) are graphs illustrating the method of consuming surplus power in this embodiment. The horizontal axis represents time [s], the vertical axis represents loss [W], and the dashed line in the figure indicates the magnitude of surplus power. Furthermore, S1 is defined as the power generated at the time when the generating torque is turned off, in other words, at the time when the power grid is interrupted due to a power outage.

[0024] If a power outage occurs in the power grid at time 0, the generator torque is turned off. As a result, the amount of power generated decreases over time until it reaches zero. In this embodiment, the power generated after this power outage, i.e., the surplus power, is consumed by losses due to increased output of the auxiliary equipment 9, losses due to decreased efficiency of the generator 1, and losses due to decreased efficiency of the power converter 2. In other words, the surplus power is consumed by generating losses, for example, by increasing the rotational speed of the radiator fan motor as auxiliary equipment 9, changing the rotor phase angle, changing the carrier frequency, etc. Hereinafter, the control for consuming this surplus power will be called surplus power suppression operation. Furthermore, losses due to increased output of auxiliary equipment 9 may be called auxiliary equipment losses, losses due to decreased efficiency of the generator 1 may be called generator losses, and losses due to decreased efficiency of the power converter 2 may be called power converter losses.

[0025] In surplus power suppression operation, the choice of whether to use auxiliary equipment losses, generator losses, or power converter losses is determined based on the magnitude of the surplus power. Since there are upper limits to auxiliary equipment losses, generator losses, and power converter losses, one or more of these losses are selected depending on the magnitude of the surplus power.

[0026] For example, as shown in Figure 2(a), if the surplus power at the time of the generator torque off (time 0) is S1, all of the auxiliary equipment losses, generator losses, and power converter losses are selected. Then, as the generator torque decreases, the surplus power decreases to S2, which can be consumed by generator losses and auxiliary equipment losses alone, and the efficiency of power converter 2 is restored to its original state (Figure 2(b)). Furthermore, when the surplus power decreases to S3, which can be consumed by auxiliary equipment losses alone, the efficiency of generator 1 is restored to its original state, and when the surplus power becomes zero, auxiliary equipment 9 is stopped (Figure 2(c)).

[0027] While any loss can be prioritized, it is preferable to prioritize losses with larger thermal time constants. In this embodiment, considering the thermal time constants of the auxiliary equipment 9, generator 1, and power converter 2, the auxiliary equipment loss, generator loss, and power converter loss are prioritized in that order. That is, since the IGBT used in the power converter 2 has a smaller thermal time constant than the generator 1 and the radiator fan motor as auxiliary equipment 9, it is given the lowest priority in order to suppress degradation due to temperature rise associated with decreased efficiency. The same applies to the relationship between the generator 1 and the radiator fan.

[0028] The degree of output increase of auxiliary equipment 9 and the degree of efficiency decrease of generator 1 and power converter 2 are predetermined based on experiments and other factors.

[0029] Furthermore, if self-consumption is possible, losses from self-consumption may also be utilized. If self-consumption is available, it may be given top priority.

[0030] Figure 3 shows an example of a time chart when the above-described surplus power suppression operation is performed. Here, we show the case where a power outage occurs at time t1, the power generation torque is turned off at time t2, and the power generation torque becomes zero at time t3.

[0031] At time t1, the decrease in generated torque begins, simultaneously with the closing operation of the first valve 6 and the opening operation of the second valve 8. As a result, the flow rate in the first channel 5 decreases and the flow rate in the second channel 7 increases in line with the decrease in generated torque, thus maintaining a constant pressure on the secondary side.

[0032] Surplus power is electricity generated after a power outage occurs.

[0033] The amount of power generated remains constant until time t2, when the power generation torque begins to decrease, and then gradually decreases over time. However, the power generated after time t1, when the power outage occurs, is considered surplus power. This surplus power is consumed by the surplus power suppression operation explained in Figure 2.

[0034] Furthermore, when changing the efficiency of generator 1 and power converter 2, the control parameters may be changed continuously. For example, when changing the rotor phase angle, the phase angle may be changed continuously based on the rotor efficiency map shown in Figure 4. This makes it possible to change to the desired operating point (efficiency) while suppressing control failure.

[0035] [Control example] Next, we will explain a specific control example of surplus power suppression operation.

[0036] The above describes a case where the power generation torque is turned off and then reduced to zero to stop power generation. However, in this control example, once the surplus power reaches a level that can be consumed by the surplus power suppression operation, the reduction in power generation torque is stopped, and power generation and surplus power suppression operation are continued. In addition, the hydroelectric power generation system is equipped with a battery 10, and if the surplus power can be absorbed by the battery, the surplus power is absorbed by the battery 10 without performing the surplus power suppression operation.

[0037] Figure 5 is a graph illustrating how surplus power is consumed in this control example. The horizontal axis represents time [s], the vertical axis represents loss [W], and the dashed line in the figure indicates the magnitude of the surplus power.

[0038] The surplus power at the time of the power outage (time 0) is S1, and the surplus power suppression operation starts from time 0, as in Figures 2(a) to (c). However, in this control example, a temperature check is performed during the surplus power suppression operation. The temperature check determines whether the temperature of the components of the power converter 2, generator 1, and auxiliary equipment 9 will exceed the component protection temperature determined by the heat resistance performance of each component, even if the surplus power suppression operation is continued with the current surplus power.

[0039] The component protection temperature can be determined in advance based on the specifications of each component.

[0040] The temperature of each component when surplus power suppression operation is continued with the current surplus power can be estimated in advance by creating, for example, power-temperature maps for each output of auxiliary equipment 9, and power-temperature maps for each efficiency of generator 1 and power converter 2.

[0041] Then, based on the temperature check at time ta, if it is determined that the temperature of each component does not exceed the component protection temperature, the reduction in power generation torque is stopped, and the surplus power suppression operation continues while maintaining the current amount of surplus power.

[0042] If power generation is stopped during a power outage, when the power is restored, the first valve 6 will start to open from its fully closed position, the second valve 8 will start to close from its fully open position, and the generator 1 will start to operate from its stopped state. As a result, the time it takes to return to normal power generation will be longer.

[0043] In contrast, according to this control example, power generation continues even during low power periods, albeit at a lower rate, allowing for a quick return to normal power generation after the power outage is resolved.

[0044] Figures 6 to 8 are flowcharts showing an example of a specific control routine for this control example. This control routine is executed when a power outage occurs in the power system 12. The priority of auxiliary equipment losses, generator losses, and power converter losses when performing surplus power suppression operation is the same as in Figure 2 described above.

[0045] In step S10, the limiting of the generated torque is initiated (turned off), and the first valve 6 is controlled to close and the second valve 8 is controlled to open.

[0046] In step S20, surplus power is calculated based on the rotational speed and generated torque of generator 1 during the power outage.

[0047] In step S30, it is determined whether the battery 10 can absorb all of the excess power. If it cannot absorb all of the power, the process proceeds to step S40. If it can absorb all of the power, the routine ends, with the battery 10 absorbing the excess power.

[0048] In step S40, it is determined whether generator losses and power converter losses are necessary for surplus power suppression operation. If necessary, the process proceeds to step S50. If not necessary, the surplus power is consumed solely through self-consumption, and the routine terminates.

[0049] In step S50, the first surplus power suppression operation is initiated. The first surplus power suppression operation is an operation method that utilizes all of the auxiliary equipment losses, generator losses, and power converter losses. In this control example, self-consumption is also performed when surplus power suppression operation is performed. This makes it possible to suppress the temperature rise of generator 1 and power converter 2 that occurs due to the decrease in efficiency.

[0050] In step S60, the temperature determination described above is performed. If it is estimated that the temperature of the component exceeds the component protection temperature, the process proceeds to step S70. If it is estimated that it does not exceed the protection temperature, the process proceeds to step S160.

[0051] In step S70, it is determined whether power converter losses are unnecessary for surplus power suppression operation. If they are unnecessary, the process proceeds to step S80; otherwise, the process returns to step S50. In other words, the determination in this step is to determine whether the surplus power can be consumed solely by generator losses and auxiliary equipment losses.

[0052] In step S80, the power converter 2 is returned to its state before its efficiency was reduced (i.e., during normal operation).

[0053] In step S90, surplus power suppression operation continues with auxiliary equipment losses and generator losses selected. This operating mode is also called second surplus power suppression operation.

[0054] In step S100, the temperature is checked again. If the component temperature exceeds the component protection temperature, the process proceeds to step S110; otherwise, the process proceeds to step S160.

[0055] In step S110, it is determined whether generator losses are unnecessary or not. If they are unnecessary, the process proceeds to step S120; otherwise, the process returns to step S90. In other words, the determination in this step is to determine whether the surplus power can be consumed solely by auxiliary equipment losses.

[0056] In step S120, the generator 1 is returned to its state before its efficiency was reduced (i.e., during normal operation).

[0057] In step S130, the surplus power suppression operation continues with only the auxiliary equipment losses selected. This operating mode is also called the third surplus power suppression operation.

[0058] In step S140, the temperature is checked again. If the component temperature exceeds the component protection temperature, the process proceeds to step S150; otherwise, the process proceeds to step S160.

[0059] In step S150, it is determined whether the surplus power has become zero. If it has not become zero, the process returns to step S130; if it has become zero, this routine terminates.

[0060] In step S160, the current operating state is maintained. That is, the reduction in generated torque is stopped, and the operation of the first valve 6 and the second valve 8 is stopped, and the surplus power suppression operation continues.

[0061] In step S170, it is determined whether the power grid has been restored from the power outage. If it has been restored, the process proceeds to step S180. If it has not been restored, the process returns to step S160 and the surplus power suppression operation continues.

[0062] In step S180, the first valve 6 is operated in the opening direction, and the second valve 8 is operated in the closing direction.

[0063] In step S190, the generated torque is restored to its original value and the system switches back to normal operation.

[0064] Figure 9 is an example of a time chart when the control routines shown in Figures 6 to 8 are executed. As in Figure 3, a power outage occurs at time t1, and at time 2, the generation torque decreases and the operation of the first valve 6 and the second valve 8 begins.

[0065] During surplus power suppression operation, if the temperature check at time t3 determines that the component temperature will not exceed the component protection temperature even if the current state is maintained, the decrease in generated torque stops, and the operation of the first valve 6 and the second valve 8 stops. As a result, the changes in the flow rate passing through the first valve 6 and the second valve 8 also stop, and consequently, the decrease in the rotational speed of the turbine 4 also stops. This state is maintained from time t3 onward.

[0066] Then, when the power outage is resolved at time t4, the generated torque and the openings of the first valve 6 and the second valve 8 are returned to their normal operating states. This reduces the time required to return to normal compared to reducing the generated torque to zero, fully closing the first valve 6, and fully opening the second valve 8 during the power outage.

[0067] As described above, this embodiment provides a control method for a hydroelectric power generation system that supplies power to a power system 12, comprising a turbine 4 arranged in a first channel 5 (water channel), a generator 1 driven by the turbine 4, a power converter 2 that converts AC power generated by the generator 1 into DC power, a controller 3 (power generation controller) that controls the power generation of the generator 1, and auxiliary equipment 9 that uses power. In this method, when a power outage occurs in the power system 12, the controller 3 starts to reduce the power generation torque of the generator 1 and consumes the surplus power, which is the power generated after the power outage, by increasing the output of the auxiliary equipment 9, decreasing the efficiency of the generator 1, or decreasing the efficiency of the power converter 2. As a result, devices such as resistors for consuming surplus power become unnecessary, or if necessary, only small ones are required, so that surplus power consumption during a power outage can be achieved while suppressing the increase in system size and cost. Furthermore, since the pressure on the secondary side of the first channel 5 can be kept constant, it can also be applied to places where it is necessary to keep the pressure on the secondary side of the water channel constant, such as the pressure reduction mechanism of water supply facilities.

[0068] In this embodiment, depending on the surplus power at the point when the generated torque begins to decrease, one or more methods are selected from increasing the output of the auxiliary equipment 9, decreasing the efficiency of the generator 1, or decreasing the efficiency of the power converter 2. By selecting the method of consuming the surplus power according to the amount of surplus power, excessive temperature rise of the components is suppressed, and thus thermal degradation of the components can be suppressed.

[0069] In this embodiment, when one or more of the following methods are being implemented—increasing the output of the auxiliary equipment 9, decreasing the efficiency of the generator 1, or decreasing the efficiency of the power converter 2—if it is estimated that continuing the method will not cause the temperature of the system components to exceed the component protection temperature determined by the heat resistance performance of the system components, the method is continued while maintaining the power generation torque at the estimated time. This allows for a quick recovery after the power outage is resolved.

[0070] In this embodiment, when all methods of increasing the output of the auxiliary equipment 9, decreasing the efficiency of the generator 1, and decreasing the efficiency of the power converter 2 are implemented, the decrease in the efficiency of the power converter 2 is terminated when the surplus power becomes less than or equal to the sum of the output of the auxiliary equipment 9 and the power loss due to the decrease in the efficiency of the generator 1. In this way, by preferentially restoring the efficiency of the power converter 2, which has the component most sensitive to temperature conditions (smallest thermal time constant) among the auxiliary equipment 9, generator 1, and power converter 2, thermal degradation of the power converter 2 can be suppressed.

[0071] In this embodiment, when the output of the auxiliary equipment 9 is increased and the efficiency of the generator 1 is reduced, the reduction in the efficiency of the generator 1 is stopped when the surplus power falls below the output of the auxiliary equipment 9. This suppresses thermal degradation of the generator 1.

[0072] The hydroelectric power generation system of this embodiment includes a first valve 6 (first flow control valve) that adjusts the flow rate of the first channel 5 (water channel), a second channel 7 (bypass channel) that branches off upstream of the turbine 4 and the first valve 6 in the first channel, bypasses the turbine 4 and the first valve 6, and rejoins the first channel 5, and a second valve 8 (second flow control valve) that adjusts the flow rate of the second channel 7. In the control method of this embodiment, the closing operation of the first valve 6 and the opening operation of the second valve 8 are started at the same time as the decrease in the power generation torque of the generator 1. This makes it possible to keep the secondary side pressure of the first channel 5 constant. In other words, the hydroelectric power generation system of this embodiment can be applied to places where it is necessary to keep the secondary side pressure of the water channel constant, such as in the pressure reduction mechanism of water supply facilities.

[0073] In this embodiment, the hydroelectric power generation system has a battery 10 in the DC voltage line, and if the surplus power can be absorbed by the battery 10, the surplus power is absorbed by the battery 10. On the other hand, if the surplus power cannot be absorbed by the battery 10, one or more methods are selected from increasing the output of the auxiliary equipment 9, decreasing the efficiency of the generator 1, or decreasing the efficiency of the power converter 2, depending on the magnitude of the power generated at the point when the generation torque starts to decrease. In this way, surplus power suppression operation is performed only when the battery 10 cannot absorb the power, so the opportunities for the components to heat up can be reduced. As a result, deterioration of components due to temperature rise can be suppressed.

[0074] In this embodiment, when the efficiency of the generator 1 or the power converter 2 is to be reduced, the efficiency is reduced by continuously changing the control parameters. This makes it possible to reduce the efficiency to the desired level while suppressing control failure. [Explanation of Symbols]

[0075] 1...Generator, 2...Power converter, 3...Controller, 4...Water turbine, 5...First channel, 6...First valve, 7...Second channel, 8...Second valve, 9...Auxiliary equipment, 10...Battery, 11...Power conditioner, 12...Power system

Claims

1. A water turbine placed in the water channel, A generator driven by the aforementioned water turbine, A power converter that converts the AC power generated by the aforementioned generator into DC power, A power generation controller that controls the power generation of the aforementioned generator, Auxiliary equipment that uses electricity, In a control method for a hydroelectric power generation system that supplies power to a power grid, The aforementioned power generation controller In the event of a power outage in the aforementioned power system, As the generator's output torque begins to decrease, A control method for a hydroelectric power generation system, characterized in that surplus power, which is power generated after a power outage occurs, is consumed by at least one of the following methods: increasing the output of the auxiliary equipment, decreasing the efficiency of the generator, or decreasing the efficiency of the power converter.

2. In the control method for a hydroelectric power generation system according to claim 1, A control method for a hydroelectric power generation system, which selects one or more methods from increasing the output of the auxiliary equipment, decreasing the efficiency of the generator, or decreasing the efficiency of the power converter, depending on the surplus power at the point when the generation torque starts to decrease.

3. In the control method for a hydroelectric power generation system described in claim 2, A control method for a hydroelectric power generation system, which, while implementing one or more of the methods of increasing the output of the auxiliary equipment, decreasing the efficiency of the generator, or decreasing the efficiency of the power converter, is estimated to continue the method while maintaining the power generation torque at the estimated time, if it is estimated that continuing the method will not cause the temperature of the system components to exceed the component protection temperature determined by the heat resistance performance of the system components.

4. In the control method for a hydroelectric power generation system described in claim 2, A control method for a hydroelectric power generation system, wherein, while all methods of increasing the output of the auxiliary equipment, decreasing the efficiency of the generator, and decreasing the efficiency of the power converter are being implemented, the reduction in the efficiency of the power converter is terminated when the surplus power becomes less than or equal to the sum of the output of the auxiliary equipment and the power loss due to the reduction in the efficiency of the generator.

5. In the control method for a hydroelectric power generation system described in claim 4, A control method for a hydroelectric power generation system, wherein when the output of the auxiliary equipment is increased and the efficiency of the generator is reduced, the reduction in the efficiency of the generator is terminated when the surplus power falls below the output of the auxiliary equipment.

6. In the control method for a hydroelectric power generation system according to claim 1, The aforementioned hydroelectric power generation system is A first flow control valve for adjusting the flow rate of the water channel, A bypass channel that branches off upstream of the water channel from the water turbine and the first flow control valve, bypasses the water turbine and the first flow control valve, and rejoins the water channel, The system includes a second flow control valve for adjusting the flow rate of the bypass channel, A control method for a hydroelectric power generation system, comprising: initiating a decrease in the power generation torque of the generator, simultaneously initiating the closing operation of the first flow control valve and the opening operation of the second flow control valve.

7. In the control method for a hydroelectric power generation system described in claim 2, The hydroelectric power generation system has a battery in the DC voltage line, If the surplus power can be absorbed by the battery, the surplus power will be absorbed by the battery. A control method for a hydroelectric power generation system, which, when the surplus power cannot be fully absorbed by the battery, selects one or more methods from increasing the output of the auxiliary equipment, decreasing the efficiency of the generator, or decreasing the efficiency of the power converter, depending on the magnitude of the power generated at the point when the power generation torque begins to decrease.

8. In the control method for a hydroelectric power generation system described in claim 2, A control method for a hydroelectric power generation system, which reduces efficiency by continuously changing control parameters when the efficiency of the generator or the power converter decreases.

9. A water turbine placed in the water channel, A generator driven by the aforementioned water turbine, A power converter that converts the AC power generated by the aforementioned generator into DC power, A power generation controller that controls the power generation of the aforementioned generator, Auxiliary equipment that uses electricity, In a hydroelectric power generation system equipped with a power grid that supplies electricity, The aforementioned power generation controller In the event of a power outage in the aforementioned power system, As the generator's output torque begins to decrease, A hydroelectric power generation system characterized in that it is programmed to consume surplus power, which is power generated after a power outage, by increasing the output of the auxiliary equipment, decreasing the efficiency of the generator, or decreasing the efficiency of the power converter, in at least one of these ways.

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