Thesis (MEng (Electrical Engineering))--Cape Peninsula University of Technology, 2019 / Electric utilities are confronted with challenges like rising fuel costs, aging equipment, increasing energy demand, frequency regulation and the difficulty to integrate renewable energy resources into the grid. The presence of photovoltaic (PV) penetration on the utility grid is also increasing significantly in recent years. With the recent rise in PV penetration and the advancement of the global PV industry, there is an urgent and a necessary need to introduce features in PV systems that will make them respond smartly. However, much of these can be addressed without negatively affecting the total performance and power quality of the grid. Hence, engaging smart Grid technologies, and leveraging the benefits of the distributed nature of PV, new prospects to unearth value can be created. Through the implementation of progressive energy storage techniques, efficient two-way communications, a grid-tied PV system can create significant value, mostly through improved PV contribution in grid support functions like frequency regulation. An enhanced frequency regulation functioning scheme for a grid-connected photovoltaic (PV) system is modelled in MATLAB/Simulink software environment. The system is designed to operate in grid ancillary services precisely, frequency regulation function. The model consists of a Photovoltaic (PV) plant with a battery connected to the grid through a three-phase inverter. A bi-directional DC-DC converter between the grid and the battery system is included. The model has a battery storage system that provide steady and regular active/reactive powers available while the grid transmit specific amounts of power needed for a specific duration. According to the design, either the grid or the PV system depending on the dominant energy situation charges the battery. The battery is designed to discharge only when the grid demands energy from the PV and if the PV system fails to meet the demanded active power or reactive power. The PV system and the battery storage is integrated with the grid with the aid of dc-ac inverter in such a manner that bi-directional flow of active and reactive power is achieved. A 1 MW PV system is connected to the utility grid through a three-phase voltage source inverter system. The grid nominal frequency is set at 50 Hz under normal operation. However, the frequency decreased when the PV was not producing required power hence, the battery responded almost instantaneously and returned the frequency to the nominal frequency. The effectiveness of battery storage system for utility grid frequency regulation was substantiated from the simulation results attained.

In Vietnam, the number of wind power generators has been increased yearly. Because of geophysical characters, the generation of these generators has different properties. It depends much on wind’s characteristics as well as the generation technology. Based on simulation implemented on Matlab, the paper analyzes the stability of national networks at PCC nods containing the connection of wind power station when there is a change of wind’s velocity or when there is an earth fault in grid. The analyzing results are used to suggest solutions to improve the stability and effectiveness of the whole system. / Các nhà máy điện gió đang ngày càng gia tăng ở Việt Nam, do cấu tạo địa lý nên đặc điểm của nguồn điện này khá khác biệt so với các nguồn điện truyền thống khác. Nguồn điện gió phụ thuộc nhiều vào đặc điểm của gió và công nghệ sử dụng để phát điện gió. Nội dung chính của bài báo là khảo sát mức độ ổn định của lưới điện kết nối các nguồn điện gió tại nút kết nối chung khi có sự thay đổi về tốc độ gió hoặc khi trong mạng xảy ra sự cố chạm đất thoáng qua, từ đó đề xuất giải pháp nâng cao ổn định, tin cậy và nâng cao hiệu quả làm việc của hệ thống.