A signal detection technique for islanding detection of distributed generators using power line signaling.

摘要

Recent developments in the electricity market have provided new opportunities for Independent Power Producers (IPP's) with small generating facilities to sell electricity to the utilities in Alberta. These generating facilities provide three major advantages: they help utilities save significant amounts of capital which they would otherwise have to invest for setting up new generation facilities, they reduce pollution by utilizing emissions for power generation and they reduce line losses due to their proximity to the load centers. For IPP's, one of the major obstacles in the way of getting permission for interconnecting with utility power lines is the islanding of distributed generator (DG). Means must be provided by either the IPP or the utility to detect this condition and disconnect the DG from the network within a specific time period after islanding. Current islanding detection techniques are expensive and may not work under certain conditions. An islanding detection scheme using distribution line signaling has been proposed by the Power Engineering group at the University of Alberta. A signal, that can be detected at all DG sites by signal detectors, is broadcast continuously from the substation. In case of islanding, detectors can no longer detect the signal, and hence the DG is disconnected from the system. This thesis discusses the development and performance evaluation of a signal detection method to be used with the proposed signaling technique. A signal detector must be capable of accurate signal detection and should have a response time in the order of 500 ms. A signal detector device has been developed and its performance has been evaluated by means of various laboratory experiments. Signal detection method is capable of accurate signal detection and indicating a loss of signal within a specified time period after the islanding takes place.