谐振补偿式电流互感器取能方法的研究

Resonance Compensation Current Transformer Energy Extraction

为解决传统电流互感器(current transformer,CT)取能装置在输电线路低电流时存在供能死区的问题,该文采用了一种谐振补偿式取能方法,通过对CT取能原理分析,推导出励磁支路参数方程式,针对目前CT取能电路中励磁支路数量级相较于变压器较低且参数难以获取,提出一种变比折算法,即通过测量副边励磁参数折算至原边,该方法可使所测得的励磁支路参数最大限度的接近于实际,从而获取最佳谐振匹配电容值。最后通过实验表明,在输电线路低电流15A时,利用所提出的变比折算法进行谐振匹配,可使CT取能功率高达1.82W,是采用传统非谐振取能方法的6~7倍,可基本满足高压输电线路在线监测设备的功率需求,具有一定的工程应用价值。

In order to solve the problem of the energy supply dead zone of the traditional current transformer(CT)energy extraction devices when the transmission line is in low current state,this paper adopts a resonance compensation energy extraction method.Through the analysis of the CT energy extraction principle,the parameter equation of the excitation branch is deduced aiming at the fact that the magnitude of the excitation branch in the CT energy acquisition circuit is lower than that of the transformer and the parameters are difficult to obtain,a variable ratio folding algorithm is proposed,which converts the excitation parameters of the secondary side to the primary side.This method makes the measured excitation branch parameters close to the actual value to the greatest extent so as to obtain the best resonance matching capacitance value.Finally,experiments show:When the transmission line is in low current 15A,the use of the proposed variable ratio folding algorithm for resonance matching reaches the CT energy extraction up to 1.82W,which is 6 to 7 times that of the traditional non-resonant energy extraction method.This method basically meets the power requirements of online monitoring equipment for high-voltage transmission lines,and has certain engineering application value.