Technical Practices of Large-Scale Wind-Solar Hybrid Power Plants: Grid Connection, Stable Power Supply, and System Coordination

Technical Practices of Large-Scale Wind-Solar Hybrid Power Plants: Grid Connection, Stable Power Supply, and System Coordination

In the construction and operation of large-scale wind-solar hybrid power plants, ensuring safe and reliable grid connection, maintaining stable power output, and effectively coordinating with grid dispatch have become key engineering challenges. Successful practices require systematic solutions at the technical, operational, and management levels.

I. Safe Grid Connection and Active Support

The connection of large-scale power plants is not merely about connecting to the grid, but more importantly, about providing friendly support and stable operation to the grid.

First, the power plant's generating equipment needs strong grid adaptability. When short-term abnormal fluctuations occur in the grid voltage, the power plant must remain connected and operational, and be able to quickly provide power support as needed to help the grid restore normal voltage.

Second, the power plant should be equipped with an intelligent control system. This system can automatically adjust the amount and characteristics of the power output from the power plant according to the grid's operating status or dispatch instructions, providing frequency and voltage regulation support to the grid. This transforms the power plant from a passive power generation unit into a friendly power source that actively participates in the stable operation of the grid.

Furthermore, the scientific selection of the power plant's grid connection location is crucial. A comprehensive grid analysis is required to assess the impact on grid security after connection. When necessary, power regulation equipment should be installed at or around the power station to maintain stable voltage at the connection point.

II. Power Output Smoothing Wind and solar power generation are inherently volatile, requiring technological means to make their output more stable and predictable.

The main solution is to configure a composite energy storage system. For short-term, drastic fluctuations, energy storage devices capable of rapid charging and discharging are used; for longer-term energy regulation, large-capacity energy storage batteries are employed. The combination of these two energy storage methods can effectively smooth out rapid changes in power station output.

The power station also requires an intelligent control system. This system, based on accurate wind and solar power generation forecasts and combined with the status of the energy storage devices, automatically calculates the optimal operating scheme. The goal is to make the energy storage devices operate more economically and efficiently while meeting the grid's constraints on power fluctuations.

For the stabilization effect, an objective evaluation method needs to be established to verify the effectiveness of the solution by comparing specific data on power fluctuations before and after stabilization.

III. Multi-level Coordination and Market Operation For large-scale power stations to effectively integrate into the power system, a multi-level coordinated operation mechanism and participation in market activities are required.

In terms of operation and management, a three-tiered coordination system of "daily planning, intraday adjustment, and real-time control" has been established. Power plants submit their generation plans one day in advance, and make rolling adjustments based on the latest forecasts on the same day, while simultaneously responding to grid fine-tuning instructions in real time.

In terms of economic operation, power plants can participate in electricity market transactions and grid ancillary services. For example, they can store energy when electricity prices are low and discharge it when prices are high to generate profit; or they can utilize their rapid response capabilities to provide the necessary regulation services to the grid.

Multiple power plants within a region can be integrated through technology to form a virtual power generation cluster. Internal scheduling within the cluster is optimized, and externally, they participate in grid operation as a whole, improving overall stability and market competitiveness.

Summary and Outlook: Large-scale wind-solar hybrid power plants are evolving from simple clean energy providers into important nodes supporting the new power system. Future development will focus on further enhancing the active support capabilities of power plants, enabling them to play a more stable and fundamental role in the grid. Simultaneously, optimizing operational strategies by combining artificial intelligence and other digital technologies will be key to improving the value and operational reliability of power plants. This process is not only a technological upgrade but also a joint advancement in operational concepts and power system collaboration methods.