Modeling And Investigation Of Communication Service Availability In WAMS

With the development of nationwide interconnected grid and smart grid, power system operation state is more complex. Based on synchronized phasor measurement technology, Wide Area Measurement System (WAMS) can dynamically monitor the grid’s operation state under a unified clock, which will greatly enhance the safe operation ability of power system. The applications of WAMS in power system demand high reliability for data communication network.According to the requirement of strongly real-time performance, synchronization algorithm characteristics of Phasor Data Concentrator (PDC) and delay mechanism of wide-area communication network are analyzed and a calculation model of WAMS communication delay is proposed. Taking the two-fiber bidirectional multiplex section protection ring as an example, study the influence of SDH network fault on real-time communication, analyze relationship between data loss and switching time length, discuss effect of protection path delay increasing on the overall communication delay of WAMS, and give some corresponding strategies.According to the requirement of the communication services performance, an evaluating indicator of communication service’s availability in WAMS is proposed, and its computation formula is established. As part of system service availability, a logic model of single service availability integrates three feature indicators of network channel reliability, transmission delay reliability and data reliability. Based on the structure of WAMS, the physical model of WAMS communication network is incorporated of four components of PMU’s communication module in sub-station, regional communication network, PDC in regional grid and backbone communication network. Then component importance for system service availability is given out. Finally, system service availability and the sorting of component importance are obtained for WAMS of IEEE14buses by Monte Carlo simulation.The research provides certain references for the construction of communication network of WAMS, PMU optimized configuration and PDC optimal placement, and then lays foundation on how to improve system reliability of WAMS.