The most important element in the electrical transmission and distribution network is the oil paper insulated transformer. For these equipments, the lifetime is determined by the condition of the insulation system (the paper and the oil). The operators have to monitor these parameters of their equipment because of the maintenance and operating reasons too. In this work, the introduced evaluating system, called Transformer Status Indicator (TSI) make a good possibility for technical evaluate and provide comparison of diagnostically results of different transformer. The result of the TSI is the base of condition based maintenance strategy. The system consider discrete diagnostically results and other environmentally parameters.
One of these diagnostic method, are introduced and developed in this work, this is the recovery voltage measurement (RVM). The RVM is based on the polarization phenomena in the oil paper insulation. The RVM method was developed in the Budapest University of Technology in the 1970. This measurement provides practical information about the insulation system (moisture, ageing) based on the Hungarian investigation of the polarization processes. There are more unprocessed results from the 1970s what are provide an extended evaluating possibilities for RVM. In this work, this extended evaluating method developed and introduced.
The TSI evaluating system can describe the condition of the insulation only a few parameters: status of the insulation, reliability and theoretically minimum and maximum values of the status. This result helps to compare conditions of the transformers. In this work, after the developing process, the TSI evaluating system tested by real data from the Hungarian distribution system. The source of the testing data is 13 HV/MV distribution transformers in Hungary.