220kV network is confronted with problems such as violation of short-circuit current constraints brought by increasing installed generation capability and system load. For restricting the value of short-circuit current of power system, 220kV network need to cooperate with 500kV network in order to avoid electromagnetic coupled power loop thus be operated in voltage-grading and district-dividing topology. Meanwhile, 220kV network is supposed to meet reliability restrictions based on N-1 principles to further ensure the responsibility as energy supplying system. Aiming at the limitation of short-circuit current, this paper proposes a bilayer model of 220kV network expansion planning with its corresponding solution algorithm considering the optimization of current limiting methods. An actual study case of expansion planning in year 2030 generated from eastern China power system is used to prove the feasibility of the mentioned methodology.
