Voltage regulation for grid connected photovoltaic systems using reactive power

Nowadays the microgrids with renewable energy sources (RESs) usage and development rapidly increase due to govermentel incentives,dropping the price of DERs and improvement of the technology. The high penetration of DERs espicialy if it is intermittent sources such as Photovoltaic (PV) sources, will effect the stability of the distribution network and causes disturbances for the voltage. To solve this issue the connected PV sources have to contribute to the stability of the distribution network. The conventional control of distrubition networks generally controlled by human which has many limitations and slow response time, so the it is important to use a real time controllers.Currently, the nine-zone diagram control (NDC) is widely used in the reactive power control (VQC) to keep voltage and reactive power within limits. This NDC plane is divided into nine regions, which determine on-load tap-changer (OLTC) and Static Var Compensators (SVCs) control strategy according the location of real-time measured voltage and reactive power. In this research the already available infrastructures (such as OLTC and SVCs) will be used in coordenation with PV sources to contribute to the voltage regulation via reactive power. The developed solution will elemenate some device failures, save budgets and improve the reialibility for both consumer and distribution network operator A case study have been carried out on a 8 bus distribution system to illustrate the effectiveness of the proposed method. This study showed how the voltage and reactive power problem can be resolved in a timely and economical way. A small scale microgrid has been simulated in this thesis and the results helped companseting distrubition grids. Matlab/Simulink have been used to verify the developed controller.