Method of controlling a pump turbine
First Claim
1. A method of controlling a pump turbine, comprising steps of controlling the quantity of water passing through a runner connected to a generator motor, changing the rotational direction of said runner so that said runner can work in a Pump-up mode or in the Power Generation mode, and controlling the quantity of water so that, when a load of said generator motor is rejected in the Power Generation mode, the rotational speed of the runner may turn to increase at a speed which is higher than the rated rotational speed or the initial speed at least one third of the difference between the first peak and the rated rotational speed or the initial speed after the first speed increase upon a load rejection turns to a speed decrease.
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Accused Products
Abstract
An object of the present invention is to provide a pump turbine capable of improving the stability of the governor by fully lessening the influences by the S-characteristics even when the running point of the pump turbine is in the S-characteristics region. For this purpose, in a pump turbine comprising a runner which is coupled with a generator motor, discharge control apparatus for controlling the quantity of water passing through the runner, and a governor for controlling said discharge control apparatus to keep the runner speed at a predetermined speed, the arithmetic apparatus of said governor is controlled to temporarily open said closing discharge control apparatus in the leading half of the speed decrease or earlier after the first speed increase upon a load rejection turns to a speed decrease upon a load rejection which abruptly shuts off power from the generator motor, so that the rotational speed of the runner goes down at much slower rate than the rate of increasing immediately after a load rejection.
8 Citations
47 Claims
- 1. A method of controlling a pump turbine, comprising steps of controlling the quantity of water passing through a runner connected to a generator motor, changing the rotational direction of said runner so that said runner can work in a Pump-up mode or in the Power Generation mode, and controlling the quantity of water so that, when a load of said generator motor is rejected in the Power Generation mode, the rotational speed of the runner may turn to increase at a speed which is higher than the rated rotational speed or the initial speed at least one third of the difference between the first peak and the rated rotational speed or the initial speed after the first speed increase upon a load rejection turns to a speed decrease.
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14. A method of controlling a pump turbine comprising steps of controlling a discharge controller for adjusting the quantity of water passing through a runner which transmits a torque to a generator motor, changing the rotational direction of said runner to pump up or generate power temporarily opening said discharge controller, just before the first rotational speed peak or in the leading half of the first speed decrease curve, putting said discharge controller under control of a rotational speed governor after a load rejection which adjusts its settings according to operation stage so that, when the rated power or near power of said generator motor is rejected, a time period between the first rotational speed peak and return of the rotational speed to the normal may be over twice as much as a time period between the start of the speed rise and the first rotational speed peak.
- 15. A method of controlling a pump turbine comprising steps of controlling the quantity of water passing through a runner which is coupled to a generator motor, changing the rotational direction of said runner to run the pump turbine in the Pump-up mode or Power Generation mode, closing said discharge controller immediately after the speed rise upon a load rejection which shuts off the power output in the Power Generation mode or in case of emergency stop, turning said discharge controller to open in the leading half of the speed rise, continuing said opening operation approximately until the speed reaches a peak, stopping the opening operation there, and closing the discharge controller.
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17. A method of controlling a pump turbine comprising steps of controlling the quantity of water passing through a runner which is coupled to a generator motor, changing the rotational direction of said runner to run the pump turbine in the Pump-up mode or Power Generation mode, closing said discharge controller immediately after the speed rise upon a load rejection which shuts off the power output in the Power Generation mode or in case of emergency stop, gradually reducing the closing rate of said discharge controller in the leading half of the speed rise, turning said discharge controller to open, continuing said opening operation approximately until the speed reaches a peak, gradually decelerating said opening operation, and thus resuming closing of the discharge controller.
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18. A method of controlling a pump turbine comprising steps of controlling the quantity of water passing through a runner which is coupled to a generator motor, changing the rotational direction of said runner to run the pump turbine in the Pump-up mode or Power Generation mode, closing said discharge controller immediately after the speed rise upon a load rejection which shuts off the power output in the Power Generation mode or in case of emergency stop, wherein said discharge controller which is closing is temporarily opened in the leading half of the first speed decrease after the first speed increase upon a full load rejection turns to the first speed decrease over a first peak.
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19. A method of controlling a pump turbine comprising steps of controlling the quantity of water passing through a runner which is coupled to a generator motor, changing the rotational direction of said runner to run the pump turbine in the Pump-up mode or Power Generation mode, closing said discharge controller immediately after the speed rise upon a load rejection which shuts off the power output in the Power Generation mode or in case of emergency stop, turning said discharge controller to open in the leading half of the speed rise, continuing said opening operation until the speed reaches a peak, stopping the opening operation there, and closing the discharge controller;
- wherein, upon a full load rejection or almost full load rejection, a time period between said first peak and the instant for the rotational speed to return as much as two thirds of the difference between the initial speed before the load rejection and said first peak is over 1.5 times as much as a time period between the load rejection point and the first speed peak.
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20. A method of controlling a pump turbine comprising steps of controlling the quantity of water passing through a runner which is coupled to a generator motor, changing the rotational direction of said runner to run the pump turbine in the Pump-up mode or Power Generation mode, closing said discharge controller immediately after the speed rise upon a load rejection which shuts off the power output in the Power Generation mode or in case of emergency stop, gradually decelerating the closing rate of said discharge controller to turn said discharge controller to open in the leading half of the speed rise, continuing said opening operation until the speed reaches a peak, gradually decelerating the opening operation, and closing the discharge controller;
- wherein, upon a full load rejection or almost full load rejection, a time period between said first peak and the instant for the rotational speed to return as much as two thirds of the difference between the initial speed before the load rejection and said first peak is over 1.5 times as much as a time period between the load rejection point and the first speed peak.
- View Dependent Claims (29)
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21. A method of controlling a pump turbine comprising steps of controlling the quantity of water passing through a runner which is coupled to a generator motor, changing the rotational direction of said runner to run the pump turbine in the Pump-up mode or Power Generation mode, closing said discharge controller immediately after the speed rise upon a load rejection which shuts off the power output in the Power Generation mode or in case of emergency stop, turning said discharge controller to open in the leading half of the speed rise;
- wherein, upon a full load rejection or almost full load rejection, a time period between said first peak and the instant for the rotational speed to return as much as two thirds of the difference between the initial speed before the load rejection and said first peak is over 1.5 times as much as a time period between the load rejection point and the first speed peak.
- 36. A method of controlling a pump turbine, comprising steps of controlling the quantity of water passing through a runner which is coupled to a generator motor by a discharge controller, changing the rotational direction of said runner to pump up or generate power, and temporarily opening the discharge controller when the power generated by the generator motor is shut off in the Power Generation mode.
- 37. A method of controlling a pump turbine, comprising steps of controlling the quantity of water passing through a runner which is coupled to a generator motor by a discharge controller, changing the rotational direction of said runner to pump up or generate power, and temporarily opening the discharge controller at least once before the runner speed reaches a point at which the speed decreasing rate is accelerated over the first peak when the power generated by the generator motor is shut off in the Power Generation mode.
Specification