According to the fact of long-term coexistence of the remote terminal unit(RTU)

the phasor measurement unit(PMU)and the advanced metering infrastructure(AMI)in active distribution networks

this paper presents a hybrid algorithm of state estimation based on hybrid measurements of RTU

PMU and AMI

which consists of nonlinear static state estimation

linear static state estimation and linear dynamic state estimation. Linear dynamic state estimation and linear static state estimation track the changes in node injected active and reactive power by utilizing PMU and RTU measurements

which can provide highly accurate virtual measurements for nonlinear static state estimation in the absence of AMI measurements. The proposed algorithm can shorten the calculation cycle and improve the accuracy of nonlinear static state estimation

while enhancing the ability of state forecasting for active distribution networks. The effectiveness of the proposed algorithm is verified by a numerical simulation. This work is supported by National High Technology Research and Development Program of China(863 Program)(No. 2014AA051901)

National Natural Science Foundation of China(No. 51261130472)and State Grid Corporation of China.