Energy Storage for Power System Planning and Operation

6Optimal Power Flow with Energy Storage System

6.1 Introduction

Optimal power flow (OPF) is one of the most widely studied nonlinear optimization problems in the power system community since it was introduced by Carpentier in 1962 [1]. It aims at finding a least‐cost schedule with the operational constraints satisfied, which acts as an important tool for economical and secure operation of power systems. Mathematically, OPF is a large‐scale nonlinear and nonconvex optimization problem, which is non‐deterministic polynomial (NP) hard and difficult to find the global optimal solution. It should be pointed out that the OPF problem we will discuss in this chapter is the so‐called alternating current (AC) OPF problem for the meshed transmission networks.

Many methods have been proposed to solve OPF problems, mainly including nonlinear programming methods and modern heuristic (artificial intelligent) approaches. These methods can be classified into deterministic, non‐deterministic and hybrid methods in references [1] and [2]. The non‐deterministic methods discussed in reference [2] are actually the various modern heuristic methods, e.g., genetic algorithm, particle swarm optimization, ant colony optimization, and artificial neural networks. Theoretically, these heuristic methods have the capabilities of finding global optimal solutions. However, they cannot guarantee to pinpoint the global optimum and often require extensive computation, especially for large‐scale power systems. Regarding ...