Simulation evaluation indices adapted to voltage stability of multi-node system

Based on dynamically measured data collected by phasor measurement unit (PMU), an online evaluation method for voltage stability in multi-node system is proposed. Firstly, utilizing aggregative index composed of sensitivity and change rate of sensitivity the weak nodes in regional power network are determined; secondly, optimally configuring PMU to weak nodes, power flow equations of power system are solved by dynamically measured data collected by PMU, and according to decoupling relations of P-θ, Q-θ and Q-V in power flow equations the changing offsets of elements in JPθ and JQU sub-matrices of Jacobian matrix are synthesized; on this basis a new kind of voltage stability indices is defined. Results of simulation on voltage stability of Shenyang regional power network show that the proposed indices can reflect variation trend and variation amplitude of voltage stability, besides, the proposed indices change slowly, so they are more intuitional than sensitivity index and using the proposed indices it is more convenient to control voltage stability.