Jawaharlal Nehru Technological University Hyderabad B.Tech IV WIND, SOLAR AND HYBRID ENERGY SYSTEMS Previous Question Paper (July - 2021 - R16)

Wind energy has been utilized for centuries, beginning with simple windmills for grinding grain and pumping water in ancient Persia and later in the Netherlands. The modern era of wind power began in the late 19th century with Charles Brush's first electricity-generating wind turbine in 1888. Following the 1970s oil crisis, research accelerated, leading to the development of large-scale horizontal-axis wind turbines (HAWTs).

Currently, wind power is a cornerstone of global renewable energy. Worldwide, the total installed capacity has surpassed 900 GW. China leads the world in total installed capacity, followed by the United States, Germany, and India. The trend is shifting significantly toward offshore wind farms, which offer higher capacity factors due to stronger and more consistent wind speeds, and the development of larger turbines with capacities exceeding 15 MW.

Integrating wind power into existing electrical grids presents several technical challenges due to the variable and intermittent nature of wind:

• Voltage Stability: Wind turbines, particularly those using induction generators, can cause voltage fluctuations at the point of common coupling, requiring reactive power compensation devices like SVCs or STATCOMs.
• Frequency Regulation: Because wind power output is non-dispatchable, sudden drops in wind speed can lead to frequency deviations, necessitating fast-acting reserves or battery energy storage systems to maintain grid frequency.
• Power Quality: Wind turbines can introduce harmonics into the grid due to the power electronic converters used in variable-speed systems, which may require harmonic filters to meet grid code standards.
• Grid Congestion: Wind farms are often located in remote areas with high wind resources, requiring significant investment in transmission infrastructure to transport power to load centers.
• Fault Ride-Through (FRT) Capability: Turbines must be designed to remain connected during grid faults to prevent cascading failures, a requirement known as Low-Voltage Ride-Through (LVRT).