Power flow control in autonomous micro-grid operation using ants colony optimization under variable load conditions

This paper presents an optimal power flow controller for a utility when the micro-grid is operating in islanded mode, based on a real time self-tuning method. Droop control strategy is presented for accurate power sharing between parallel connected inverters in an AC micro-grid islanded mode. The controller scheme is composed of an inner current control loop and an outer power control loop based on a synchronous reference frame and the conventional PI regulators. A new control scheme based on a combination of droop control and ant colony optimization (ACO) algorithm is proposed in this paper. Droop control aims to share the load change after islanding occurs. ACO is an intelligent searching algorithm that is applied for real-time self-tuning of the power control parameters. The proposed strategy role is that the required load power is shared equally between the micro-grid and the utility based on the ACO algorithm during the load change. These are implemented using code in the Matlab-Simulink environment. The simulations show that the proposed scheme which combines droop control with ACO algorithm could operates well in both grid islanded mode conditions.