{'fraction_non_alphanumeric': 0.021714285714285714, 'fraction_numerical': 0.0, 'mean_word_length': 5.3478260869565215, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Investigation of electrical tree propagation from water tree by utilizing partial discharge and optical observation

In order to clarify the mechanism of electrical tree propagation from a water tree within polyethylene, we have carried out simultaneous observation of partial discharge (PD) characteristics, electrical-tree propagation and associated phenomena. The electrical tree inception voltage increases with the area of water tree degradation. An electrical tree is initiated from a water needle tip. When the electrical tree connects with water needle, PDs become large abruptly. There are two types of electrical-tree growth, in one of which only small PDs occur only at the electrical-tree tips. After removing the applied voltage, water fills the electrical-tree channels, and water trees propagate from the electrical-tree tips when the voltage is applied again.