| Due to electric tree under high electric field, the life of polymer is very short.So in order to improve the insulation property of polymer, different types of nanoparticle is added into polymer. In the same time, the partial discharge detectiontechnology can diagnose the property of insulation material.A partial discharge detection system is built on the basis of Rogowski. First,the best parameter of Rogowski is confirmed using Matlab simulation software.Then the Rogowski is made according to the optimized parameter. Then theamplitude-frequency test circuit is used to get the real amplitude-frequency curveof Rogowski.The partial discharge detection system is used to classify different types ofdischarges in gas, liquid, and solid. The frequency of the three types of partialdischarge is4.2MHz、4.4MHzand11.5MHz. The electric tree initiationexperiment is built based on different content of MMT. The results showthat,when the length of electric tree reach30mm, the growth of electric tree willstop. The amplitude of partial discharge will grow at first, then the amplitude willdecrease. The biggest discharge amplitude will show at30minutes. The figure ofelectric tree and amplitude of discharge of composite is compared, after applyingvoltage for30minutes. The shortest length of electric tree is177μm, whichshows in composite of0.5%content of MMT. The number of partial dischargesignal and frequency of signal also reach the lowest value.The content of MMTcan also change the shape of electric tree. Comparing to pure PE composite, thecomposite which contain0.5%MMT will have more complicated shape of tree.The path of electric will bend more seriously. When the content of MMT reach1%, the path of electric tree will grow. When the content of MMT reach3%, thetrunk of electric does not increase, but the number of branch of trunk is growing... |
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