Method of controlling wicket gates of a pump-turbine
AssigneeHitachi, Ltd.
InventorsTakao Kuwabara, Hiroshi Okumura
Life of this patent
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Abstract
A method of controlling wicket gates of a pump-turbine which prevents abnormal hydraulic pressure variation when load carried on the pump-turbine is removed during the turbine operation thereof. The wicket gates are controlled to open when it is detected that discharge per unit head reduces with the reduction of speed per unit head. When it is once detected that the ratio of variation in the discharge per unit head to the variation in the speed per unit head is reversed from a positive value to a negative value, the wicket gates are closed.
Claims124
In a method of controlling wicket gates of a pump-turbine upon removal of load from said pump-turbine, said pump-turbine being of the type having in the turbine operation area S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship, .differential.Q.sub.1 /.differential.N.sub.1 >0, the improvement which comprises the steps of slowly closing said wicket gates when the ratio (.differential.Q.sub.1 /.differential.N.sub.1) of variation of the discharge per unit head to the speed per unit head is reduced than a predetermined negative value, continuing the slow closure of said wicket gates while said pump-turbine operates tracing said S-section, and rapidly closing said wicket gates as soon as the ratio, .differential.Q.sub.1 /.differential.N.sub.1, is once reversed from a positive value out of said S-section to a negative value.
In a method of controlling wicket gates of a pump-turbine upon removal of load from said pump-turbine, said pump-turbine being or the type having in the turbine operation area S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship, .differential.Q.sub.1 /.differential.N.sub.1 >0, the improvement which comprises the steps of forcibly opening said wicket gates when the ratio (.differential.Q.sub.1 /.differential.N.sub.1) of variation of the discharge per unit head to the speed per unit head is reduced than a predetermined negative value, continuing the forcible opening of said wicket gates while said pump-turbine operates tracing said S-section, and rapidly closing said wicket gates as soon as the ratio, .differential.Q.sub.1 /.differential.N.sub.1, is once reversed from a positive value out of said S-section to a negative value.
In a method of controlling wicket gates of a pump-turbine of the type which has in the turbine operation area S-section where discharge per unit head (Q1) and speed per unit head (N.sub.1) satisfy the relationship, .differential.Q.sub.1 /.differential.N.sub.1 >0, the improvement which comprises the steps of opening said wicket gates when the turbine operation of said pump-turbine is effected on the S-section upon removal of load from said pump-turbine, and, when said pump-turbine operates outside said S-section, closing said wicket gates as rapidly as possible under condition that the hydraulic pressure variation caused by the rapid closure of said wicket gates becomes substantially equal to the hydraulic pressure variation caused in the S-section.
A method of controlling the wicket gates of a pump-turbine to prevent abnormal pressure rises when load carried by the pump-turbine is removed during the turbine operation, with respect to a turbine having wicket gates closable and openable to control the flow of fluid through the turbine impeller and having a S-section of its performance as a turbine defined by .differential.Q.sub.1 /.differential.N.sub.1 >0, wherein Q.sub.1 is the discharge fluid through the impeller per unit head and N.sub.1 is the impeller speed per unit head, comprising the steps of:
- upon removal of load from the pump-turbine, reducing Q.sub.1 and approaching the S-section;
- thereafter opening the wicket gates within the S-section;
- and
- thereafter closing the wicket gates.
A method of controlling the wicket gates of a pump-turbine to prevent abnormal pressure rises when load carried by the pump-turbine is removed during the turbine operation, with respect to a turbine having wicket gates closable and openable to control the flow of fluid through the turbine impeller and having an S-section of its performance as a turbine defined by .differential.Q.sub.1 /.differential.N.sub.1 >0, wherein Q.sub.1 is the discharge fluid through the impeller per unit head and N.sub.1 is the impeller speed per unit head, comprising the steps of:
- detecting the removal of load from the turbine and in response to detecting the load removal, closing the wicket gates upon removal of load from the pump-turbine to reduce Q.sub.1 and approach the S-section without completely closing the wicket gates;
- thereafter detecting when the pump-turbine is operating within the S-section so that the discharge per unit head Q.sub.1 is decreasing and discontinuing said step of closing when Q.sub.1 is decreasing;
- and
- thereafter detecting when the discharge per unit head Q.sub.1 is increasing within the S-section and closing the wicket gates in the S-section when the discharge per unit head Q.sub.1 is increasing.
A method of controlling the wicket gates of a pump-turbine to prevent abnormal pressure rises when load carried by the pump-turbine is removed during the turbine operation, with respect to a turbine having wicket gates closeable and openable to control the flow of fluid through the turbine impeller under the control of a regular controller, such as a speed governor, and having an S-section of its performance as a turbine defined by .differential.Q.sub.1 /.differential.N.sub.1 >0, wherein Q.sub.1 is the discharge fluid through the impeller per unit head and N.sub.1 is the impeller speed per unit head, comprising the steps of:
- upon removal of load from the pump-turbine, reducing Q.sub.1 and approaching the S-section with the wicket gates being closed under control from the regular controller;
- thereafter putting the wicket gates under an overriding control within the S-section which allows only closing speed substantially stopping and very slow closing or opening signals from said regular controller and, for any faster closing signals from said regular controller outside said closing speed range, gives an overriding signal for substantially holding at the current wicket gate position;
- and
- thereafter closing the wicket gates.
In a method of controlling wicket gates of a pump-turbine of the type showing during turbine operation the performance that discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship, .differential.Q.sub.1 /.differential.N.sub.1 >0, comprising the steps of:
- slowly opening said wicket gates upon removal of load from said pump-turbine;
- temporarily increasing the opening speed of said wicket gates during said slowly opening step when the pump-turbine is operated tracing the S-section in the Q.sub.1 -reducing direction (dQ.sub.1 /dt is negative).
A method of controlling wicket gates of a pump-turbine of the type which has in the turbine operation area an S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship .differential.Q.sub.1 /.differential.N.sub.1 >0, comprising the steps of:
- detecting a condition where said pump-turbine is operating tracing said S-section in the Q.sub.1 -reducing direction;
- and
- when said detecting step detects said condition, putting said wicket gates under an overriding control which allows only opening signals of a faster rate than a fixed rate from a regular controller (such as a speed-governor) and, for any slower rate, opening signals or closing signals from said regular controller gives an overriding opening signal of faster than or equal to said fixed rate.
A method of controlling wicket gates of a pump-turbine of the type which has in the turbine operation area an S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship .differential.Q.sub.1 /.differential.N.sub.1 >0, comprising the steps of:
- detecting a condition where said pump-turbine is operating tracing said S-section in the Q.sub.1 -increasing direction;
- and
- when said detecting step detects said condition, putting said wicket gates under an overriding control which allows only closing signals of faster rate than a fixed rate from a regular controller (such as a speed-governor) and, for any slower rate closing signals or opening signals from said regular controller gives an overriding closing signal of faster than or equal to said fixed rate.
A method of controlling wicket gates of a pump-turbine of the type which has in the turbine operation area an S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship .differential.Q.sub.1 /.differential.N.sub.1 >0, comprising the steps of:
- detecting a condition where said pump-turbine is operating tracing said S-section in the Q.sub.1 -reducing direction,
- and
- when said detecting step detects said condition, putting said wicket gates under an overriding control which allows only substantially stopping or opening signals from a regular controller (such as a speed-governor) and, for any faster closing signals from said regular controller, gives an overriding signal for substantially holding at the current wicket gate position.
A method of controlling wicket gates of a pump-turbine of the type which has in the turbine operation area an S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship, .differential.Q.sub.1 /.differential.N.sub.1 >0, comprising the steps of:
- detecting a second condition where said pump-turbine is operating tracing said S-section in the Q.sub.1 -increasing direction, and
- when said detecting step detects said second condition, putting said wicket gates under an overriding control which allows only substantially stopping or closing signals from a regular controller (such as a speed-governor) and, for any faster opening signals from said regular controller, gives an overriding signal for substantially holding at the current wicket gate position.
In a method of controlling wicket gates of a pump-turbine upon removal of load from said pump-turbine, said pump-turbine being of the type having in the turbine operation area an S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship, .differential.Q.sub.1 /.differential.N.sub.1 >0, the improvement which comprises the steps of slowly closing said wicket gates when the ratio (.differential.Q.sub.1 /.differential.N.sub.1) of variation of the discharge per unit head to the speed per unit head is reduced than a predetermined negative value or turns to positive, continuing the slow closure of said wicket gates while said pump-turbine operates tracing said S-section, and rapidly closing said wicket gates as soon as the ratio, .differential.Q.sub.1 /.differential.N.sub.1, is once reversed from a positive value to a negative value, out of said S-section.
In a method of controlling wicket gates of a pump-turbine upon removal of load from said pump-turbine, said pump-turbine being of the type having in the turbine operation area an S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship, .differential.Q.sub.1 /.differential.N.sub.1 >0, the improvement which comprises the steps of forcibly opening said wicket gates when the ratio (.differential.Q.sub.1 /.differential.N.sub.1) of variation of the discharge per unit head to the speed per unit head is reduced than a predetermined negative value or turns to positive, continuing the forcible opening of said wicket gates while said pump-turbine operates tracing said S-section, and rapidly closing said wicket gates as soon as the ratio, .differential.Q.sub.1 /.differential.N.sub.1, is once reversed from a positive value to a negative value, out of said S-section.
In a method of controlling wicket gates of a pump-turbine of the type which has in the turbine operation area an S-section where discharge per unit head (Q.sub.1) and speed per unit head (N.sub.1) satisfy the relationship, .differential.Q.sub.1 /.differential.N.sub.1 >0, the improvement which comprises the steps of opening said wicket gates when the turbine operation of said pump-turbine is effected in the Q.sub.1 -reducing direction in the S-section upon removal of load from said pump-turbine, and, when said pump-turbine operates outside said S-section, or tracing the S-section in the Q.sub.1 -increasing direction, closing said wicket gates as rapidly as possible under condition that the hydraulic pressure variation caused by the rapid closure of said wicket gates becomes substantially equal to the hydraulic pressure variation caused in the S-section.
Dependencies are inferred from the claim text.