Research And Design On The Digital Interface Of Electronic Current Transformer

There is electromagnetic saturation in traditional CTs, so the traditional CT can't meet relay protection in some situation. Now, the Electronic CT based on Rogowski coil can substitute traditional CT. Its solidity is very small, and its linearization is good. Besides, it outputs digital signal, and this can improve its EMC capacity.The author of this paper researched the digital interface of the electronical CT, and designed an experimental equipment. This equipment has two parts: one data-sampling section, another is processing communication section. The data-sampling section completes analogue-to-digital conversion using FPGA and high speed ADC, then transmits these data to processing communication equipment in some format. Because FPGA has high speed processing capacity, this section can obtain very high sampling rate. Processing communication section collects data from data-sampling section, and gives them to network controlling chip. In this section, a single FPGA chip receives data from six channels simultaneously. Digital phase lock loop is used in this section to synchronize to an incoming serial data stream.