An advanced technique for frequency domain spectroscopy of oil-paper insulation at reduced time using triangular excitation

This paper presents an advanced method for condition monitoring of oil-paper insulation of the transformer using accelerated dielectric response measurement. In frequency domain spectroscopy, dielectric response current is measured for a period of two cycles over a wide range of frequencies. Such measurements on real life transformers take long time in practice especially in the lower frequency range which is practically problematic. Considering the above-said fact, a new technique has been developed in the present work that can reduce the measurement time significantly. Instead of using the excitation for two cycles, quarter cycle of the excitation is applied on insulation under test. The method is verified on three test samples having different preset moisture contents. The dielectric dissipation factors of the test samples computed from the proposed method, are then compared with the corresponding values calculated for two cycles of the applied excitation. The results show negligible differences in the values of dissipation factors of the test samples obtained with the applied excitation for two cycles with that of quarter cycle.