Parameters affecting the turn insulation lifetime and durability

To assess the condition of turn insulation, a test sample has been proposed by IEC/TS 60034-18-42. The proposed test sample cannot evaluate all of the practical aspects of the turn insulation. In addition, the partial discharge inception voltage (PDIV) of the proposed test sample has a dependency on the length and thickness of the copper strands. By replacing the proposed test sample with a completed coil as a proper test sample, all practical conditions of the turn insulation can be assessed. In this paper, using a completed coil sample, the effects of the various issues such as thickness of the turn insulation, thickness of the copper strand, the VPI process, the voltage waveform on the (PDIV), and the lifetime behavior of the turn insulation can be evaluated.