Communication Scheme of Phasor Measurement Unit in WAMS

The communication scheme of synchronous Phasor Measurement Unit (PMU), which has been developed in the form of double CPUs: Digital Signal Processor (DSP) and high-speed AVR MCU, is presented in this paper. The Serial Peripheral Interface (SPI) is used to communicate between the DSP and the AVR MCU in the PMU, and it allows PMU to operate independently to measure, record, and display and transfer both the instantaneous and phase data. The Universal Serial Bus (USB) Interface is adopted to transfer both the instantaneous and phase data between PMU and industrial PC to realize the analysis and control of the local system. The CAN bus and the industrial Ethernet are combined to transfer the only phase data to the measurement center to accomplish the analysis and control of the global system.