Development on the zero-flex type current sensor

The on-line monitoring of high voltage equipment is an important technique to ensure the safe of electric power transmission. And the key of the technique is the detection of divulge current. At first, the error of the current transducer is analyzed. Then a type of low current transducer with cored structure and high accuracy is described which is specially designed for on line monitoring of high voltage apparatus. The circuit in the transducer can track the variation of magnetizing current and compensate it by single chip processor systems. Through adjusting the phase and amplitude of compensation current, to assure the magnetic core working in zero-flux condition. The test of the current transducer shows that the design gets satisfactory results. Its angular difference is plusmn2.0psila, relative scale difference is under 1/1000, and its resolution is about 100 muA.