Design Of Hybrid Fiber Current Transducer

As important equipments in electric power industry, current transducers play a primary role for working well and calculating precisely in power supplying system. With the development of national economy, new high voltage level emerges continuously, and high accuracy of calculation and protection are demanded increasingly. It is an unavoidable trend that electric current transducer substitutes the old electromagnetic current transducer. Based on modern electronics technology and optical technology, hybrid fiber current transducer has already accepted by electric power engineering for his attractive characteristics of high accuracy, high reliability and wide bandwidth.In order to satisfy the demanding for electric current transducer in modern electric power industry, this issue designed a hybrid fiber current transducer that can work well and at the same time, coincide with the rule of international standard. We use Rogowski coil as the sensor that mounted on high voltage power line. After converting Rogowski coil's analog signal to digital signal, we transmit the digital signal to low voltage part through POF where we resume the analog signal and finish the tasks of measurement. The whole circuit's timing generation and synchronization was realized with CPLD. As the channel of data transmitting, POF can isolate high voltage part and low voltage part efficiently. At the same time, a single chip processor was used to design a digital meter for the fiber current transducer.From the experiments we can get a conclusion that with the characteristics of working well, sample circuit and light path, rated current error and phase error fulfilling accuracy class 0.2, and respond speed and bandwidth superior to old electromagnetic current transducer, the hybrid current transducer we designed is practical.