Research On The On-line Detecting Instrument For The Insulators On High Voltage Lines

With the fact that the national economy promptness develops, the electric system transmission line voltage grade improves also quickly, insulators in the transmission lines were located in very bad complicated natural environment for long time, so contamination flashover is always aroused. To guarding against contamination flashover, performing the real-time monitor of insulator is a crucial task to solve the safety of transmitting electricity wires. It could heighten the level of preventing contamination flashover, and enable the overhaul of insulators to changing from scheme to state overhaul.After refering to a great deal of domestic and overseas literature and analyzing all kinds of the characteristic of detecting ways, we offer the detecting way of polluted insulator flashover based on acoustic emission technique. By analyzing the discharge process of polluted insulator and concomitant acoustic emission phenomenon, the characteristics of acoustic signal are studied, and the relationship between discharge and acoustic signal is revealed in this paper. A new method of insulator discharge monitoring based on the acoustic emission technique is put forward.In order to catch the acoustic signal produced by contaminant discharge, a focused acoustic sensor with high sensitivity and data collecting circuit are designed. The focused acoustic sensor combined by discharge at a distance. The acoustic emission signal under different contamination level and different voltage grade are collected in the insulator's artificial pollution test by using this set of equipment. By comparing the acoustic emission signal during different phase of contaminant discharge, it proved that the amplitude and continuity of acoustic signal increase along with the boost up of contaminant discharge.In order to make the detecting way come true, we design a kind of detecting instrument to change the analog signal of the focused acoustic sensor to the digital signal, and transfer the result to the monitor centre. Meanwhile, we think of the disturb factors and suggest interference protection measure. We offer the corresponding hardware and software anti-jamming measure to make data collection more exact.At last, the data obtained in the experiments are analyzed using fuzzy mathematics tools, and results prove that the capacitance between discharge and flashover can be calculated by the acoustic signal and fuzzy discursion is very effectual. It indicated that we offered the detecting way not only being able to be used to carry out online detecting on the insulator, but also making correct judgement to the contamination level of insulator.