海上风电场交流并网系统振荡风险分析及基于短路比的评估计算原则研究

Oscillation Risk Analysis of AC Grid-Connected System of Multi-Offshore Wind Farms and Evaluation and Calculation Principles Based on Short-Circuit Ratio

近年来海上风电快速发展,受电网建设周期影响,有时需要安排并网过渡运行方案以提高海上风电利用率。以广东某地区海上风电为例,针对规划方案和过渡运行方案振荡风险问题开展评估,研究了多风电场汇聚并网方式下短路比计算方法和风电并网容量确定原则,以及集控站SVG对并网容量的影响。研究表明,海上风电经交流海缆并网,风电机组和SVG共同与交流电网之间存在较强的相互作用,使得低风速情况下风电并网系统存在振荡风险,且集控站用于补偿海缆充电无功功率的SVG容量限制了风电并网容量,因此按照短路比计算风电并网容量时需要考虑SVG容量。在此基础上提出了提升海上风电并网容量的技术措施以适应并网过渡方案的运行要求。

In recent years, the rapid development of offshore wind power has been affected by the construction period of the power grid. Sometimes it is necessary to arrange a grid-connected transitional operation plan to increase the utilization rate of offshore wind power. Taking offshore wind power in a certain area of Guangdong as an example, this paper evaluates the oscillation risk of planning schemes and transitional operation schemes, and studies the calculation method of short-circuit ratio under the mode of convergent and grid-connected multiple wind farms and the principle of determining the grid-connected capacity of wind power and the influence of centralized control station static var generator(SVG) on grid-connected capacity. Results show that offshore wind power is connected to the grid via AC submarine cables, and there is a strong interaction between wind turbines and SVGs and the AC grid, which makes the wind power grid-connected system at low wind speeds have a risk of oscillation. Moreover, the capacity of the SVG used to compensate the reactive power of submarine cable charging at the centralized control station limits the grid-connected capacity of wind power. Therefore, the SVG capacity needs to be considered when calculating the wind power grid-connected capacity according to the short-circuit ratio. On this basis, technical measures of increasing the grid-connected capacity of offshore wind power are proposed to meet the operational requirements of the grid-connected transition plan.