Generation of a PLC based unit protection device to monitor the abnormal operation of transformer
Distribution transformers of substation are one of the most important equipment in power system network. Because of the large number of transformers and various components over a wide area in power systems, the data acquisition, condition monitoring, automatic controlling are the important issues. This paper presents design and implementation of automatic control circuits which is used in PLC automation to monitor as well as diagnose condition of transformers, like load currents, transformer temperatures and voltages. The proposed on-line monitoring system integrates a solid state device named PLC (programmable logic controllers). The suggested plc monitoring system will help to detect the fault. PLC based solution is to be provided to get a reliable and fail-safe TRIP signal for Unit Protection devices; in case of abnormal operating condition of a Generator Transformer. This device should monitor the status of large number of analog inputs of all the eighteen cooler units and on sensing failure should generate the respective output signal.