The research on thermal expansion and thermal compensation method of Rogowski coils
Hongling Zhang,Bin Hong,Yuan Gui,XiaoqingYang
COMPUTER MODELLING & NEW TECHNOLOGIES 2014 18(12D) 74-78
Hebei construction engineering college, Zhangjiakou, China
Rogowski coils are mostly used to measure AC current, pulse current and transient current in power industry. Thermal expansion can change the structural parameter of the coils when the ambient temperature varies, so it affects the measurement precision of Rogowski coils. The mathematical model of the thermal expansion effect on measurement precision of Rogowski coils is proposed in this paper. The ratio voltage error caused by thermal expansion effect is identical with the ratio error of coils mutual inductance, that is obtained by Matlab simulation. The thermalcompensation method that can eliminate the thermal expansion effectonRogowski coilsis introduced, that is, a compensation ring is embedding in Rogowski coils former. The mathematical model of thermal compensation is proposed, and it is verified by Matlab simulation. The experimental results show that the ratio voltage error tendency with temperature is the same as the error tendency from theoretical analysis and the limitation of measurement precision relates with coils thermal expansion; It may eliminate the thermal expansion effectonRogowski coils to embeda compensation ring in Rogowski coils former.