Control apparatus for variable-speed hydraulic power generating system

• US 4,754,156 A
• Filed: 10/16/1987
• Issued: 06/28/1988
• Est. Priority Date: 10/17/1986
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd., Kansai Electric Power Company Incorporated
• Original Assignee: Hitachi, Ltd., Kansai Electric Power Company Incorporated
• Inventors: Bando, Akira, Kuwabara, Takao, Nakagawa, Hiroto, Haraguchi, Eiji, Shiozaki, Junichi
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US07/109,167
• Time in Patent Office: 256 Days
• Field of Search: 290/42, 290/43, 290/44, 290/45, 290/52, 290/53, 290/54, 290/55, 290/40 C, 318/586, 318/588, 318/589, 415/1, 415/2, 415/3, 415/4, 415/5, 415/6, 415/7, 416/3, 416/7, 416/9, 416/119, 416/132 B, 417/330-333, 60/495-509, 322/29, 322/35
• US Class Current: 290/52
• CPC Class Codes: F03B 15/08 by speed, e.g. by measuring electric frequency or liquid flow
• CPC Class Codes: Y02E 10/20 Hydro energy

Abstract

Disclosed is a control apparatus for a variable-speed hydraulic power generating system comprising a variable-speed a.c. electric generator connected to an a.c. electric power system and a hydraulic machine system including a water turbine for driving the generator and a guide vane for controlling an amount of water supplied to the water turbine. The control apparatus comprises a frequency converter connected between the electric power system and the generator for controlling electric power supplied from the generator to the electric power system, control means operating in response to at least an externally applied power generation command signal for controlling, on one hand, the frequency converter thereby controlling the electric power supplied from the generator to the electric power system and generating, on the other hand, a guide-vane opening command signal for controlling the guide vane thereby controlling the amount of water supplied to the water turbine, and means for reducing resonance which may occur in the hydraulic machine system when the rotation speed of the water turbine changes in response to a change of the externally applied power generation output command signal.

Claims

1. A control apparatus for a variable-speed hydraulic power generating system comprising a variable-speed electric generator electrically connected to an a.c. electric power system and a hydraulic machine system including a water turbine for driving the generator and a guide vane for controlling an amount of water supplied to the water turbine, said control apparatus comprising:

a frequency converter connected between said electric power system and said generator for controlling electric power supplied from said generator to said electric power system;

control means operating in response to input signals including at least an externally applied power generation command signal for controlling, on one hand, said frequency converter thereby controlling the electric power supplied from said generator to said electric power system and generating, on the other hand, a guide-vane opening command signal for controlling said guide vane thereby controlling the amount of water supplied to said water turbine;

means for detecting a water pressure applied to said water turbine; and

means for correcting said guide-vane opening command signal according to a variation of said detected water pressure.

2. A control apparatus according to claim 1, wherein said electric generator is an induction generator of secondary excitation type, and said frequency converter is connected between said electric power system and a secondary excitation winding of said induction generator.

3. A control apparatus according to claim 2, wherein said control means includes means for adjustably setting a signal indicative of the water level of water supply to said water turbine.

4. A control apparatus according to claim 3, wherein said means for detecting the water pressure applied to said water turbine generates an output signal having a level adjusted to correspond to an effective water level of said water supply when the flow rate of water supplied to said water turbine is constant.

5. A control apparatus for a variable-speed hydraulic power generating system comprising a secondary-excitation type induction generator having a primary winding connected to an a.c. electric power system, secondary-excitation control means connected to a secondary winding of the induction generator for controlling the excitation of the secondary winding of the induction generator according to an externally applied power generation command signal thereby controlling the output of said induction generator, a water turbine for driving said induction generator, a guide vane for adjusting an amount of water to be supplied to the water turbine, a rotating speed command operator for determining an optimum rotating speed command signal based on at least said externally applied power generation command signal, means for detecting a rotating speed of said generator, means for producing a guide-vane opening command signal based on a difference between said optimum rotating speed command signal and the detected rotating speed of the generator, means for controlling an opening of the guide vane according to said guide-vane opening command signal, means for detecting a water pressure applied to said water turbine and means for correcting said guide-vane opening command signal according to a variation of said detected water pressure.