Multi-channel system for remote power quality monitoring of distribution power stations in low and medium voltage supply networks is presented in the paper. The goal was to develop low-cost, space saving device that could simultaneously take measurements from all (usually eight or up to twelve) outgoing three-phase feeders in distribution substation. In that case, we should perform at least 3 voltage measurements and 36 current measurements at the same time. In order to save space, but not to reduce the measurement accuracy, a data acquisition system is designed based on real-time multiprocessing with microcontroller and FPGA circuit. Voltage and current measurements and their corresponding high-order harmonics are calculated using fast FPGA circuit, while other calculations (power, power factor, voltage and current phase angles, etc.) are performed in microcontroller. Further savings are obtained using multichannel analog input modules with multiplexed inputs. Communication with supervising computer is done using GPRS modem or wireless network module depending of station location. Results obtained on the developed industrial prototype confirm proposed solution.
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