| 摘要 |
An embedded generator protection apparatus and method to more accurately detect "islanding" or "loss of mains" in which measurements of operational parameters of the local electricity supply, in particular rate of change of frequency or vector shift, are made at two separate locations on the grid, and the measurements compared to determine whether or not a measured fault in the vicinity of the generator is a local or a system wide disturbance, thereby avoiding inadvertent or unnecessary operation of the generator protection. A signal sending relay (34) at a first location, such as a major substation (30), monitors the local rate of change of frequency of the supply and issues a signal to protection apparatus (44) and (54), at a second location, in the vicinity of an embedded generator (42) and (52), in dependence on supply characteristics at the first location. The receipt of the signal by the protection apparatus may simply indicate that the protection is not to operate, or alternatively the signal may be used to determine whether to operate protection or not. |
