In large electrical grids often have emergencies and power outages. To prevent them, it is necessary to measure network parameters. One such parameter - it synchrophasor. It is measured at different points of the electrical network in the same time. Comparing the values of synchrophasor different points of the network, it is possible to assess its condition and to prevent emergency.
The problem or task
For the research tasks it was necessary to develop a distributed PMU-system. She had to measure the value of the synchrophasor. The maximum amount of time synchronization between the systems should not exceed 1 μs. The sections of the power grid are at a great distance from each other. Therefore it was necessary to use GPS-synchronization of measurements.
To solve the problem, a voltage and current synchrophasor measurement system has been developed. The joint use of several systems installed at different parts of the electrical network made it possible to compare the measurement results. The NI CompactRIO-9024 controller with the NI CompactRIO-9118 FPGA chassis was chosen as the basis for the PMU system measuring device. Voltage measurement was carried out by a three-channel voltage measurement module NI 9225. Current measurement was performed by a four-channel current measurement module NI 9227. GPS signals were received by the NI 9467 module. The software was developed in the LabVIEW programming environment. It calculated the synchrophasor value and assigned precise time stamps from the GPS to each measurement. The NI FPGA Timekeeper software module was used to time-stamp the measurement. The program for calculating the synchrophasor value was developed using the NI LabVIEW Electrical Power Suite module. The program transmits the synchrophasor values to a remote server. It analyzes measurement data from multiple systems. Based on the results, the condition of the electrical network section is determined. The developed PMU system made it possible to measure the synchrophasor using GPS synchronization. The value of the time desynchronization between the measuring systems did not exceed 1 μs.