Multi-objective optimal siting and sizing of BESS considering transient frequency deviation and post-disturbance line overload

With the development of renewable energy sources, more frequent and severe active power disturbances emerge in power systems, and jeopardize the frequency stability and line loading security. The battery energy storage system (BESS) is able to adjust output power flexibly, and an attractive solution to improve frequency dynamics and power flow distribution. This paper proposes a multi-objective optimal siting and sizing scheme for the BESS to arrest frequency excursion and mitigate line overload under major disturbances. First, an extended average system frequency model is developed to estimate the required transient frequency regulation capability (TFRC) for frequency stability, and the post-disturbance power flows. Then, taking the required TFRC and line capacity as constraints, a multi-objective optimization model is established to minimize the life cycle cost of the BESS and generation cost. Furthermore, based on the linear weighted method, big-M method, and multi-cut generalized Benders decomposition, the intractable optimization model is transformed into a master problem for investment decision making, and a set of subproblems accounting for normal operation, frequency stability and line loading security. Additionally, the master problem and subproblems are solved iteratively to determine the location and capacity of the BESS. Case studies are conducted to validate the proposed scheme, showing superior performance in improving frequency nadir and alleviating post-disturbance line overload.