Variable-speed operation control apparatus and hydroelectric power generation system

Patent metadata

Field	Value
Publication number	US-2016248357-A1
Application number	US-201615046631-A
Country	US
Kind code	A1
Filing date	Feb 18, 2016
Priority date	Feb 23, 2015
Publication date	Aug 25, 2016
Grant date	—

Abstract

According to one embodiment, there is provided a variable-speed operation control apparatus of a hydroelectric power generation system including a power generator interconnected to a power system through a main circuit and a water turbine directly connected to the power generator. The apparatus includes a branch circuit branched from the main circuit and including a frequency converter which performs conversion between an output frequency of the power generator and a system frequency of the power system, wherein the power generator is interconnected to the power system through the branch circuit when a flow rate of water is less than a fixed level.

First claim

1 . A variable-speed operation control apparatus of a hydroelectric power generation system including a power generator interconnected to a power system through a main circuit and a water turbine directly connected to the power generator, the variable-speed operation control apparatus comprising:
a branch circuit branched from the main circuit and including a frequency converter which performs conversion between an output frequency of the power generator and a system frequency of the power system, wherein the power generator is interconnected to the power system through the branch circuit when a flow rate of water is less than a fixed level.

2 . The variable-speed operation control apparatus of the hydroelectric power generation system according to claim 1 , wherein:
the main circuit includes a first breaker; the branch circuit includes a second breaker connected in series to the frequency converter; and when the flow rate of water is less than the fixed level, the first breaker is switched from a closed position to an open position and the second breaker is switched from an open position to a closed position.

3 . The variable-speed operation control apparatus of the hydroelectric power generation system according to claim 1 , wherein:
the main circuit includes a breaker; the branch circuit includes a semiconductor switch connected in series to the frequency converter; and when the flow rate of water is less than the fixed level, the breaker is switched from a closed position to an open position and the semiconductor switch is switched from an open position to a closed position.

4 . The variable-speed operation control apparatus of the hydroelectric power generation system according to claim 1 , further comprising:
a controller which performs control of, when the flow rate of water is less than the fixed level, switching an interconnection route to interconnect the power generator with the power system through the branch circuit and reducing a rotation speed of the power generator and the water turbine by operating the frequency converter.

5 . The variable-speed operation control apparatus of the hydroelectric power generation system according to claim 4 , wherein the controller obtains information indicative of a flow rate of water, and when the flow rate is less than a predetermined value, the controller performs control of switching the interconnection route to interconnect the power generator with the power system through the branch circuit.

6 . The variable-speed operation control apparatus of the hydroelectric power generation system according to claim 4 , wherein the controller obtains information indicative of a water level of a reservoir and calculates a drop from the water level, and when the drop is smaller than a predetermined value, the controller performs control of switching the interconnection route to interconnect the power generator with the power system through the branch circuit.

7 . The variable-speed operation control apparatus of a hydroelectric power generation system according to claim 4 , wherein the controller obtains an output of the power generator, and when the output is smaller than a predetermined value, the controller performs control of switching the interconnection route to interconnect the power generator with the power system through the branch circuit.

8 . The variable-speed operation control apparatus of a hydroelectric power generation system according to claim 4 , wherein the controller obtains an output of the power generator in a case of using the branch circuit and an output of the power generator in a case using the main circuit without using the branch circuit, and when a greater one of these outputs is smaller than a predetermined value, the controller performs control of switching the interconnection route to interconnect the power generator with the power system through the branch circuit.

9 . A hydroelectric power generation system including the variable-speed operation control apparatus according to claim 1 .

Assignees

• Toshiba Kk

Inventors

• Mori Junji
• Nakazono Masahiko
• Osada Oki
• Shiozaki Yuichi
• Asano Takeyoshi

Classifications

• F03B15/00 Primary

  Controlling (controlling in general G05 {; regulation of plants characterised by the use of siphons F03B13/086}) · CPC title

• H02P27/00

  Arrangements or methods for the control of AC motors characterised by the kind of supply voltage (of two or more motors H02P5/00; of synchronous motors with electronic commutators H02P6/00; of DC motors H02P7/00; of stepping motors H02P8/00) · CPC title

• H02J3/38

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title

• H02P1/52

  by progressive increase of frequency of supply to motor · CPC title

• H02P9/42

  to obtain desired frequency without varying speed of the generator · CPC title