Application of Moth Flame Optimization Algorithm for AGC of Multi-Area Interconnected Power Systems

Introduction

An electric power system consists of several areas and interconnected through tie-lines. It consists of several generating units and loads in each area. The generating units operate at a nominal frequency for successful operation. A frequency deviation is a direct result of the imbalance between the electrical power generations with total load demand and associated system losses (Elgerd, 2008; Bervani & Hiyama, 2011; Kothari & Nagrath, 2011). Depending on the diversity of frequency deviation range, in addition to the natural governor response known as the primary control, the supplementary or secondary control and emergency control may also be required to maintain power system frequency (Bervani & Hiyama, 2011). In normal operation, the small frequency deviations can be damped out by the primary control loop. For larger frequency deviations, according to the available amount of power reserve, the secondary control loop i.e. automatic generation control (AGC) is responsible for restoring system frequency to nominal value. However, for a serious imbalance between generated power and load demand associated with rapid frequency changes following a significant fault, the AGC system may be unable to restore frequency. In this situation, the emergency control and protection schemes must be used to decrease the risk of cascade faults, additional generation events, load/network, and separation events. Thus, the function of AGC is to maintain frequency and tie-line power close to the scheduled values under normal operation and small load perturbations.