Abstract
Polypropylene (PP) has no cross-linking process and environmentally friendly properties and is considered to be a replacement for cross-linked polyethylene (xlpe) for high voltage direct current (HVDC) cable insulation. High-voltage DC cable systems generate repetitive pulse voltages during operation and may encounter different temperature environmental challenges. This chapter discusses the effects of pulse amplitude and frequency on PP trees at different temperatures. A higher pulse frequency accelerates the propagation of the tree. Higher amplitudes accelerate tree growth and fractal dimensions. In addition, the effects of DC voltage, pulse voltage, and pulse frequency on the tree characteristics of PP at DC voltage and pulse combination voltage are also studied.