Efficient Compression of PMU Signal Using Ramanujan's Sum Transform

The Phasor Measurement Unit (PMU) forms the basis of a Wide Area Monitoring, Protection, and Control (WAMPAC) system. PMUs capture time-synchronized voltage and current phasors at a higher reporting rate of 50–60 samples per second using Information and Communication Technology (ICT) enabled Global Positioning System (GPS). This results in a significant amount of data that needs to be stored and transmitted for analysis in the control center. Therefore, an efficient PMU data compression scheme is necessary to reduce the cost of storage and the bandwidth required to transmit this data. In this paper, a simple PMU signal compression scheme consisting of 2 modules is proposed. Module 1 separates the event window from the steady state window using Statistical Variance (SV). This results in improved compression and reconstruction performance. Next, Module 2 compresses the separated windows using Ramanujan's Sum Transform (RST) method. The effectiveness of the proposed method is then compared with the conventional Discrete Cosine Transform (DCT) for various types of disturbances in the IEEE 14-bus system. Finally, the results demonstrate the effectiveness of the proposed method, while future direction is discussed at the end of the paper.