Voltage regulation of medium voltage distribution system in the presence of decentralized generation unit

Abstract

The electric power distribution network has traditionally been operated in a passive mode where most of the electricity was generated by large power plants, delivered to the customers through distribution networks. Thus the flow of real and reactive power was from the higher to the lower voltage levels. Recently, distributed generations (DG) with renewable energy are expected to play an increasing role in emerging electric networks in response to the climate change challenge and the need to enhance fuel diversity. With the introduction of the DG, the power flows may become reversed since the distribution network is no longer a passive circuit supplying loads but an active system with power flows and voltages determined by the generation as well as load. Due to the fact that distribution network has been designed to work in the passive form, increasing power injections from DG units results in numbers of negative impacts. Voltage control problem can be addressed as one of the major impacts of using DG units in power system and the voltage rise effect is regarded as a key factor that limits the amount of additional DG capacity that can be connected to the distribution networks. The aim of this project is to study the different techniques of voltage control, which are employed on the distribution networks including DG units. The first part of this project consists of overview about the traditional structure of powers system and its characteristics. After that, we study the impacts of using DG units in distribution system. On the next part, different voltage control techniques will be presented and their main advantages and disadvantages will be introduced. For a better understanding of these techniques, different simulations will be done using NEPLAN software.