电力系统可靠性评估计算复杂度高，难以嵌入电力系统扩容规划模型中。为了实现考虑可靠性的系统扩容规划，提出了一种基于负荷可行域和可靠性跟踪的电力系统扩容规划模型及其求解算法。首先，提出基于负荷可行域的近似距离模型，将可靠性评估中的切负荷计算从优化问题求解转变为方程求解，降低可靠性评估计算复杂度。其次，基于近似距离模型，建立可靠性指标对设备容量的灵敏度模型，实现针对设备容量的可靠性跟踪。最后，提出了以可靠性提升为目标的电力系统扩容规划模型，提出基于可靠性跟踪和贪心算法的优化求解算法。算例结果表明：近似距离模型能够有效降低可靠性评估的计算复杂度；灵敏度模型能够正确反映设备容量变化对系统可靠性的影响；扩容规划模型及求解算法能够达到最优的系统扩容规划结果。

Power system reliability evaluation is a high-dimensional nonlinear problem, which is difficult to be nested into the power system expansion planning model. This paper presents a power system expansion planning model and its solution algorithm based on load feasible region model and reliability tracking. Firstly, an approximate distance algorithm is proposed based on load feasible region. The approach transforms the optimization problem of load shedding calculation required into an equation solving. On this basis, the analytical expression of reliability sensitivity to components’ capacity is obtained. The reliability tracking oriented to capacity are obtained. Finally, a reliability-oriented capacity expansion planning model is proposed, and a solution algorithm based on reliability tracking and greedy algorithm is proposed. The results show that the approximate distance model can effectively reduce the computational complexity of reliability evaluation; the sensitivity model can accurately reflect the influence of equipment capacity on system reliability; the capacity expansion planning model and algorithm can achieve optimal system capacity expansion planning results.