What is the difference between grid connected and off grid wind turbines?

1、 System composition
Grid connected wind turbines: Grid connected wind turbine systems are relatively complex, mainly composed of key components such as wind turbines, step-up transformers, grid connected inverters, and transmission lines connected to the power grid. The electricity generated by wind turbines is first boosted by a step-up transformer to meet the requirements of power grid transmission. Subsequently, the grid connected inverter converts the AC power into AC power that matches the grid voltage, frequency, and phase, ensuring that the electrical energy can be smoothly integrated into the grid. This system configuration enables grid connected wind turbines to efficiently and stably deliver electrical energy to the grid.
Off grid wind turbines: In contrast, the system composition of off grid wind turbines is relatively simple. It mainly consists of wind turbines, controllers, batteries (optional), and loads. The electricity generated by wind turbines is directly supplied to the load, and if equipped with batteries, it can provide power support in case of insufficient wind power. Due to not being connected to the power grid, off grid wind turbines do not require complex equipment such as grid connected inverters.
2、 Operation mode
Grid connected wind turbines: The operation mode of grid connected wind turbines is strictly regulated and restricted by the power grid. When the electricity generated by wind turbines exceeds the local load demand, the excess electricity will be transmitted to the power grid for use in other regions; When the wind is insufficient or the generator malfunctions, electricity can be obtained from the grid to meet the load demand. This operating mode enables grid connected wind turbines to fully utilize the compensation and support functions of the power grid, and more fully develop available wind resources.
Off grid wind turbines: Off grid wind turbines operate independently and are not affected by the power grid. Its power generation is entirely dependent on wind resources and load demand. When the wind is sufficient, the electricity generated by the generator can not only meet the load demand, but also store the excess electricity in the battery (if equipped) for use in case of insufficient wind. This operating mode makes off grid wind turbines particularly suitable for remote areas that cannot be covered by the power grid, such as pastoral areas, forest areas, communication base stations, etc.
3、 Applicable scenarios
Grid connected wind turbines: Grid connected wind turbines are mainly used in large wind power plants, which are usually composed of dozens or even hundreds of wind turbines with a capacity of several megawatts to several hundred megawatts. Grid connected wind power plants can receive compensation and support from the power grid, and more fully develop available wind resources, which is the main development direction of wind power generation at home and abroad.
Off grid wind turbines: Off grid wind turbines are mainly suitable for areas where the power grid cannot effectively cover, such as remote mountainous areas, islands, border posts, etc. Due to their remote geographical location or harsh natural conditions, these areas are difficult to cover with power grids or have high construction costs. Off grid wind turbines provide reliable power supply to these areas through independent power generation and energy storage systems.
4、 Technical features
Grid connected wind turbines: Grid connected wind turbines place greater emphasis on compatibility and stability with the power grid in terms of technology. Its grid connected inverter requires precise control of output voltage, frequency, and phase to ensure synchronous operation with the power grid. At the same time, grid connected wind turbines also need to have active and reactive power regulation and low voltage ride through capabilities to ensure that the wind turbines are not connected when the power grid fluctuates.
Off grid wind turbines: Off grid wind turbines place greater emphasis on power generation efficiency and the reliability of energy storage systems. Due to not being connected to the power grid, off grid wind turbines need to independently undertake the power supply task of the load, so their power generation efficiency and energy storage system performance are crucial. In addition, off grid wind turbines also need to have automatic safety protection systems to cope with harsh natural environments and emergencies.
There are significant differences between grid connected and off grid wind turbines in terms of system composition, operation mode, applicable scenarios, and technical characteristics. Grid connected wind turbines are suitable for large-scale wind power plants, closely connected to the power grid to achieve effective transmission and distribution of electricity; Off grid wind turbines are suitable for remote areas that cannot be covered by the power grid, providing reliable power supply to the local area through independent power generation and energy storage systems.