A two-port black-box external equivalent method using improved branch outage simulation

Abstract Due to the guarded nature of technology and industry with respect to their proprietary information, real-time data sharing among subsystems of an interconnected power grid is not a viable option. To estimate external equivalent parameters accurately when the external network information is unavailable or not considered, a two-port black-box external equivalent method, using an improved branch outage simulation based on direct current (DC) power flow (BOSDC) approach, is proposed as an alternative to some existing non-topology based, static equivalent techniques with an assumption lies in that the state of the external network remains almost unchanged before and after the branch outage. Moreover, use of BOSDC improves the accuracy of equivalent parameters and the performance of static security analysis in particular by retaining the quadratic term, which is represented as the product between network susceptance increment and the voltage phase angle increment. The linearity of the parameter estimation equation in the proposed method gets rid of potential issues with setting initial values and convergence criteria. Additionally, the significant power flow change before and after the branch outage can effectively adapt the interference of measurement errors. Simulation results on the modified IEEE 39-bus system and the practical Guangdong-Hong Kong power system verify the effectiveness of the proposed method.