Microgrid is a new concept in generation of modern electricity. Microgrids are becoming attractive to consumers because of utilization of freely available renewable energy sources. They are usually installed at consumer’s sites i.e. at the distribution end. Microgrids are designed to maintain loads in service when the utility fails. A microgrid’s on-site power generation helps reduce energy losses in transmission, further increasing efficiency of the electric delivery system.
Certain factors affecting the power system are voltage sag, swell and harmonics. Main cause for voltage sag in the system are due to faults occurring in the system but can also be caused by energization of large loads in the system or starting of large motors. On the other hand voltage swells are caused by sudden switching off a large load in the system or even can be due to energizing a large capacitor bank. Voltage sags and swells results in failure and malfunction of equipments that eventually leads to reducing the life span of devices.
This project presents modeling of Microgrid system comprising of solar photovoltaic system, wind power generation system and battery system. Switching of loads can cause power quality events like voltage sag and swell in the system. This problem largely affects the consumer appliances leading to failure of equipment. This issue can be overcome by custom power device specifically Dynamic voltage restorer (DVR). This device mitigates the problem of voltage sags, swells and harmonics occurring in microgrid.
A microgrid is modeled and simulated in Matlab/Simulink. Then the performance of DVR, is evaluated by causing power quality problems. In microgrid, voltage sag and swell has been occurred due to load change. When a large load is added to the system sag occurs and when a load is removed suddenly then voltage swell occurs. Voltage sag is also caused by faults in the system. This project address the power quality problems such as voltage sag, swell in the microgrid. These cases are discussed in this project and the performance of DVR based on Proportional integral (PI) controller has been investigated in improving the power quality in microgrid system in Simulink software