Space Electric Field Characteristics in Oil of Large-Scale Oil-Pressboard Structure under Various Voltage Stresses
Gao Chunjia1, Qi Bo1, Han Hao1, Gao Yuan2, Li Chengrong1
1. State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing 102206 China; 2. State Grid Shandong Rizhao Power Supply Company Rizhao 276800 China
Abstract The design of oil-pressboard/paper insulation structure mainly relies on simulation and verification test with simple equivalent test models, which lacks the physical entity verification under the large-scale structure. Based on Kerr electro-optic effect, a novel electric field measuring sensor was developed to capture the electric field in a large-scale converter transformer outlet device model under AC voltage, DC voltage and polarity reversal voltage. The test results indicated that ①under the positive DC voltage, as the voltage duration prolongs, the electric field in outer oil spacing decreases while those in inner and middle oil spacing both increase, and the field strength in steady state is increased by 2.04 times compared with the calculation results via RC (Resistance-Capacitance) model. Under the negative DC voltage, the tendency of electric field is similar to that under positive voltage; ②Under AC voltage, the maximum error between measured field strength and simulation result is 4.08%; ③Under the polarity reversal voltage, the faster the polarity reversal time, the higher the electric field strength after polarity reversal in the oil. In addition, the different interface charge accumulation conditions in each oil spacing could cause the zero-crossing point of electric field to be asynchronous with that of applied voltage. Based on the dynamic process of interface charge and its influence on space electric field, this paper proposes an electric analysis method for explaining the time-dependent characteristic mechanisms of electric field and interface charge in oil under DC voltage and polarity voltage.
Gao Chunjia,Qi Bo,Han Hao等. Space Electric Field Characteristics in Oil of Large-Scale Oil-Pressboard Structure under Various Voltage Stresses[J]. Transactions of China Electrotechnical Society, 2019, 34(22): 4816-4826.
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2019, Vol. 34 
