Multi Channel On-Line Monitoring System for Power Transformers

Abstract:
Monitoring of power transformers provides useful information about the current operation condition and can avoid unexpected outages. Furthermore it supports the decision concerning the transformer operation under competitive conditions within liberalised energy market. On-line monitoring allows detecting a failure at any time and also during the normal operation of the transformer. On-line measurements offer also the advantage that data can be pursued during a longer period with almost the same operating conditions. Then, slow changes can be detected and a warning message or command for an immediately trip-off can take place, if limit values are crossed. The combination of an on-line monitoring system for partial discharge measurement, tan δ measurement of the high voltage bushings and the measurement of the winding transfer function seems to be an efficient system. In this contribution the single monitoring system as well as the combined system will be described. In addition the practical measurements in the laboratory will be presented including the developed sensors and the software.