Optimal coordinated volt/var control in active distribution networks

Voltage regulation in active distribution systems (ADN) becomes more challenging due to distributed generation (DG) interference with the conventional voltage control devices. The reasons behind that are the reverse power flow which is caused by the DG units and the probabilistic nature of renewable-based DG units. In this paper, a GA-based voltage regulation schemes is proposed to determine the optimal settings for the DG reactive powers. Moreover, a new hysteresis controller for the on-load tap changer (OLTC) is proposed, which utilizes the system´s maximum and minimum voltages, to provide a proper voltage regulation when the OLTC feeds multiple feeders. The proposed control algorithms are coordinated to achieve an effective voltage regulation with less tap operation and DG reactive power. The proposed coordination is tested using a radial structure distribution network which is modeled using Matlab.