On-Line Assessment Of Steady State Voltage Stability Based On Wide-Area Measurement System

Now the development of grid interconnection, the growth of load in electric powerreceiving end systems and farther deregulation of power systems, more and morevoltage stability problems will be emerged in power system operation. With the flyingdevelopment of computer technology and communication technology, especial thewidely application of the WAMS in power system, voltage instability based on WAMSis becoming all increasingly important worldwide issue．The equivalent parameterestimation and on-line voltage stability index at weak buses of network side based onWAMS is presented in this paper. The varying properties for local nodal voltage andcurrent are analyzed theoretically. Directly using the WAMS to collect the measuredvalue of local voltage and current vector can realize the online estimate and instructionof the voltage stability degree of key node, the index is simple and clear in physicalconception as well as linear On the basis of the above reasons, this paper furtherresearches the phase failure problem of slack node, this paper puts forward twoprocessing methods: One is putting forward that taking the voltage phase of the nodewhich has the nearest electric distance from the slack node as the reference phase canalso realize online assessment of the voltage stability of the key node. The other ispredicting nodal voltage phasor and nodal current phasor with historical data of theWAMS and algorithm of least square fit curve, this method can also realize onlineassessment of the voltage stability of the key node. This paper takes PSASP simulationsoftware as simulation tool, taking IEEE36-node system the research object. Themethod is suitable for the surveillance of online static voltage stability of node and has acertain feasibility, which has been verified by simulation with IEEE36-node system.