热膨胀对Rogowski线圈测量准确度的影响

Rogowski线圈主要用在测量交流电流、脉冲电流、电力系统中的暂态电流等方面.它具有输出功率低、结构简单、线性度良好等优点.当周围温度变化,热膨胀会改变线圈的截面面积.为了分析热膨胀对Rogowski线圈测量准确度的影响,引入了一个描述单位温度变化线圈感应电压的比率误差的参数,得出了计算热膨胀引起的电压比率误差的数学模型,分析了矩形截面线圈和圆形截面线圈以便于比较热膨胀对不同截面形状线圈测量准确度的影响.试验数据表明,电压的比率误差随温度的变化趋势与理论分析一致;由线圈的缠绕线和骨架引起的误差总和包括在测量误差之内.这对于设计高准确度的Rogowski线圈是非常有用的.

Analysis of the Thermal Expansion Effect on Measurement Accuracy of Rogowski Coils

Rogowski coils are mostly used to measure AC current, pulse current and transient current in power industry. Rogowski coils have the advantages of small output power, simple configuration and ideal linearity. Thermal expansion can change the cross-sectional area of the coils when the ambient temperature varies. In order to analyze the thermal expansion effect on Rogowski coils in this paper, a parameter is introduced, which can be described as the ratio error of induced voltage per unit rise in temperature. The parameter is a function of the thermal expansion coefficient of the material. Mathematical models are developed for calculating the ratio error caused by thermal expansion effect. Rogowski coils with rectangular cross section and with circular cross section are analyzed in order to compare the thermal expansion effect on measurement accuracy of coils with different cross section. The experimental results indicate that the ratio voltage error tendency with temperature is the same as the error tendency from theoretical analysis; the summation of two kinds of ratio errors caused by the coil winding and the coil former is included within errors from measurement. It is instructive in design the high precision Rogowski coils.