PROTECTION ARRANGEMENT OF AN ELECTRIC POWER SYSTEM

• US 20120139264A1
• Filed: 08/06/2010
• Published: 06/07/2012
• Est. Priority Date: 08/12/2009
• Status: Active Grant

• Current Assignee: Wartsila Italia SPA (Wärtsilä Corporation)
• Original Assignee: Awek Industrial Patents Ltd. Oy (Berggren Oy)
• Inventors: Riihimäki, Vesa
• Granted Patent: US 8,736,090 B2
• Time in Patent Office: Days
• US Class Current: 290/40.B
• CPC Class Codes: H02P 9/04 Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• CPC Class Codes: H02P 9/105 for increasing the stability
• CPC Class Codes: H02P 9/107 for limiting effects of overloads

Abstract

The inventive protection arrangement of an electric power system comprises a relay arrangement (12) for measuring current, voltage or both of an electric grid (15). The relay arrangement is adapted to detect over-current, under-voltage or both. The protection arrangement comprises also a speed/load controller (16) that is in connection with the relay arrangement (12). The speed/load controller is arranged to drive a prime mover (11) of a generator (10) set as a response for the said detection. The speed/load controller (16) is connectable with said prime mover (11). In more detail the controller (16) is arranged to drive power output of the prime mover (11) to a lower level when over-current, under-voltage or both is detected.

Claims

1. A protection arrangement of an electric power system comprising a relay arrangement for measuring current, voltage or both of an electric grid, which relay arrangement is adapted to detect over-current, under-voltage or both, wherein the protection arrangement comprises a speed/load controller that is in connection with the relay arrangement, which speed/load controller is arranged to drive a prime mover of a generator set as a response for the said detection, said speed/load controller being connectable with said prime mover, the speed/load controller driving power output of the prime mover to a lower level when over-current, under voltage or both is detected.

2. The arrangement according to claim 1 wherein, in response to said detection, the driving of the power output to the lower level is arranged to initiate during a fault of the power system and before a critical clearing time of a generator of the generator set

3. The arrangement according to claim 2 wherein the speed/load controller is arranged to drive power output of the prime mover to an higher level when the detection of over-current, under-voltage or both ceases.

4. The arrangement according to claim 1, wherein the speed/load controller comprises a fault detection unit.

5. The arrangement according to claim 1, wherein the relay arrangement comprises an instrument transformer.

7. The method according to claim 5, wherein the adjusting phase is arranged to drive power output of the prime mover to a lower level in response to the detection signal.

6. A method for protecting an electric power system, the method comprising a phase for measuring at least one current and voltage of an electric grid, the method further comprising phases for forming a detection signal in case of measurement of at least one of over-current and under-voltage, and adjusting speed/load control of a prime mover of a generator set in response to the detection signal.

8. The method according to claim 6, wherein the adjusting phase is arranged to drive power output of the prime mover to an higher level when the detection signal of at least one of over-current and under-voltage ceases.