CPC H02J 3/388 (2020.01) [H02J 3/381 (2013.01); H02H 7/26 (2013.01)] | 15 Claims |
1. A method for preventing islanding in a power distribution network that could occur as a result of distributed power generation sources in the network, said network including a power line having a first and second end, a plurality of transformers electrically coupled to and positioned along the power line, each transformer including a source side switching device and a load side switching device, wherein source power is provided to the first and second ends of the power line and wherein one of the switching devices is a normally open switching device, said method comprising:
detecting loss of voltage to the network;
opening the source side switching device in at least the transformers nearest the first and second ends of the power line;
detecting that voltage has been restored to the network;
measuring the voltage at the source side of the transformers having open source side switching devices;
measuring the voltage at the load side of the transformers having open source side switching devices;
measuring the voltage on a transformer bus between the source side and load side switching devices of the transformers having open source side switching devices; and
closing the source side switching devices that have been opened if there is an acceptable relationship in measured source side voltage, load side voltage and transformer bus voltage.
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