The Research And Design On Rogowski Coil Sensor Head Of Electronic Current Transformer For Measurement

At present, electromagnetic current transformer are widely used in the power system.Their working principle is similar with conventional transformers. However, with the transmission capacity and the voltage level of the power line increasing, conventional electromagnetic current transformer are found to have many insurmountable questions. For example, more complicated insulation between the primary winding and the secondary causes the larger size, heavier weight and higher cost. Because of the nonlinear factors of the ferrous core, such as eddy current and hyteresis loss when the core is saturated with large malfunction current, ratio error and phase error are very large. The CTs can't work because the oil in the conventional transformer possibly blow up for the bad-working environment. The opening of the secondary circuit will yield high voltage that is potentially dangerous to the instrument and operators. So it is necessary to study the novel current transformer that are based on the new working principle.In view of the electric power industry to the electronic current transformer's request, electronic current transformer was researched and designed according to the standard of the international IEC60044-8 "Electronic Current Transformer". Rogowski coils used as a high-voltage power line sensor head.After the output of Rogowski coils was digitalized,then transmitted to low-voltage terminal through fiber-optic to carry out LED display or restore the original analog signal,so the high-voltage power-side bus current was measured. The system used fiber-optic digital transmission to achieve high-voltage side and low-voltage side of the complete electrical isolation and signal transmission , enhanced the signaling anti-jamming.And used microcomputer interface technology ,including data output and analog output ,to achieve data collecting, processing and adjusting,it provided a good interface to post-measurement equipment and automation equipment.A/D conversion circuit was the core of high-voltage side, this paper focused on the design of high-voltage side of the high-precision, high reliability, low power A / D conversion interface circuit. In addition, this paper also discussed power supply scheme of active devices in high-voltage side, a new power supply circuit was proposed; the electronic circuit anti-jamming of high-voltage side was discussed and designed,and the accuracy of the measurement system was improved.The experiment proved that the electronic current transformer designed was simple and practical,which had good linear degree and measure precision,and could measure current in the wide range.These current transformer have many virtues,Such as response speedily,wide bandwidth ete.Comparing with the traditional electromagnetic current transformer,questions such as being flammable and explosive caused by oil,the magnetism saturation and insulation between the high-voltage and low-voltage,that the electronic current transducer designed has been overcame because of the loweost,wide bandwidth.Simple and practicality the electronic current transformer have greater application prospects.