Avoiding the Non-Detection Zone of Passive Loss-of-Mains (Islanding) Relays for Synchronous Generation by Using Low Bandwidth Control Loops and Controlled Reactive Power Mismatches

作者：Roscoe Andrew J^*; Burt Graeme M; Bright Chris G

来源：IEEE Transactions on Smart Grid, 2014, 5(2): 602-611.

DOI：10.1109/TSG.2013.2279016

• AC generators
• AC generator excitation
• islanding
• loss-of-mains
• power generation
• power systems
• power system control
• power system protection
• power system security
• protective relaying
• reactive power

Generation connected to electrical distribution systems requires reliable and timely detection of loss-of-mains (islanding). Passive loss-of-mains detection relays typically use measurements of parameters such as frequency, phase, and the magnitudes of voltage and current. If a part of the power network becomes islanded and there is a very close match between generation and demand of both active and reactive power, there is a risk that the relay will not be able to detect the loss-of-mains (LOM) event quickly, or perhaps at all. This is the "non-detection zone"or NDZ. This paper proposes a combination of 2 generator control techniques which allow the NDZ to be avoided even when the generator has significant inertia. Firstly, the natural instability (when islanded) of a grid-connected control scheme consisting of integral and droop controls is recognized and exploited. Secondly, a simple strategy is added which makes occasional small, steady-state adjustments to the reactive power output of the generator. The scheme has been tested in the laboratory and shows that the 2 second detection time required by IEEE 1547 can be achieved, even when an exact match of active power generation and demand is initially configured, and the generator has a significant inertia.

• 出版日期2014-3