采用双磁路的电流互感器在线取电方法

On-line Power Acquiring Method of Current Transformer with Dual Magnetic Circuit

针对目前应用较为广泛的电流互感器在线取电装置存在磁路易饱和、取电功率较小等问题,提出双磁路拓扑结构与谐振功率控制相结合的在线取电方法。在双磁路结构中,一个两半圆磁芯安装于输电线路上,通过二次侧接入电容使磁路中的励磁电感与电容发生并联谐振,增大该磁路阻抗值,从而控制线路上的电流更多流入双磁路另一磁路线圈,并通过该磁路实现内部阻抗与外部负载值匹配,获取最大功率。基于该取电方法,提出调整谐振电容的磁芯防饱和方法,使取电装置维持高取电功率的同时正常工作。采用Maxwell与Simplorer的联合仿真验证了该取电方法的正确性和线路谐波情况下的适用性。初步搭建的取电装置实验表明,双磁路取电功率满足高压输电线路监测设备需求。

Aiming at the problems such as easy saturation of magnetic circuit and low acquired power of the widely used on-line power acquiring device of current transformer,this paper proposes an on-line power acquiring method combining dual magnetic circuit topology with resonant power control.In the dual magnetic circuit structure,a two-semicircle magnetic core is installed on the transmission line,and the excitation inductance in the magnetic circuit is resonant in parallel with the capacitance through the secondary-side connection capacitor,which increases the impedance value of the magnetic circuit.Thus,the current on the line is controlled to flow more into the other magnetic circuit coil of the dual magnetic circuit,through which the internal impedance is matched with the value of the external load,and the maximum power is obtained.Based on this method,an anti-saturation strategy of magnetic core controlled by excitation inductor and resonant capacitor is put forward,which makes the device keep high acquired power while work normally.The correctness of the method and the applicability for the circuit harmonic are verified by the joint simulation of Maxwell and Simplorer.The preliminary test shows that the power acquired by the dual magnetic circuit can meet the requirement of monitoring equipment of high voltage transmission line.