To adapt to randomness and volatility caused by large-scale renewable energy integration

a new online computation method of Thevenin equivalent parameters is proposed using single operation state section data based on wide area measurement. First of all

the load of bus is handled to be equivalent impedance; Second

the original admittance matrix of system is modified by the equivalent impedance of bus load; Finally

using the revised admittance matrix and node voltage equation

the open circuit voltage of load bus can be computed as Thevenin equivalent electric potential according to the definition of the Thevenin equivalent

then all the Thevenin equivalent parameters can be obtained. On the basis of this method

the Thevenin equivalent parameters can be accurately calculated on condition that the generator reactive power output reaches its limit (PV-PQ transitions). Simulation results show the correctness

effectiveness and high calculating accuracy even during PV-PQ transitions of this method. This is supported by National Natural Science Foundation of China (No. 51177091) and State Grid Corporation of China (No. XT71-15-056).