一种适应母线电流动态范围宽的光电式电流互感器供电电源

A Kind of Power Supply of Optic-electric Current Transformer for Accommodating Wide Bus Dynamic Current

针对现有采用电流互感器(CT)供电的光电式电流互感器(OECT)的供电电源,受本身热耗始终随母线电流增大而增大的限制,适应母线电流动态范围较窄的问题,提出了一种基于CT次级电流大小来控制CT变比,以降低电源热耗的方法。电源变换与稳压单元,采用固态继电器分流CT次级电流,由迟滞比较器输出的占空比随CT次级电流变化的脉冲控制固态继电器,实现电源输出电压稳定;CT变比控制单元,采用传感线圈检测CT次级电流,并通过另一迟滞比较器控制继电器,实现CT变比切换,使CT次级电流始终保持在预先设定的范围内。研制的供电电源,适应母线电流的动态范围为现有的20倍以上。

Aiming at solving the problem existing in the current optic-electric current transformer（OECT） power supply with current transformer（CT） power supply, namely its poor adaptability to the dynamic range of bas current resulted from its heat consume always increasing with bas current, a method of decreasing the heat consume of power supply by basing on the second current of CT to control CT ratio is proposed in this paper. In the power transformation and voltage regulator unit, the solid-state relay splits the second current of CT, and is controlled by the output pulse of hysteresis comparator, which duty-cycle changes with the second current of CT. According to the above method, the output voltage of power supply can be stabilized; In the CT ratio control unit, the sensor coil is used to detect the second current of CT, and the relay is controlled by another hysteresis comparator to realize the CT ratio transformation and keep the CT second current in the prearranged range. The adaptability of the developed power to the dynamic range of bas current is over 20 times that of the conventional power supply.