新能源基地经特高压交流送出系统输电能力与提升措施

Transmission Capacity and Improvement Measures of the UHVAC Sending System from New Energy Base

随着新能源在电力系统中占比不断增加,大规模新能源安全稳定送出能力提升成为一个普遍关注的问题。以张北地区千万千瓦级新能源基地经张北—雄安1 000 kV特高压交流输电线路送出为例,使用电力系统分析综合程序(power system analysis software package, PSASP)搭建了其机电暂态仿真模型,其中包含具备低电压穿越功能的新能源模型及分布式调相机模型,分析了新能源送出能力的制约关键因素,研究了分布式调相机配置对于新能源短路比的影响,最后通过全数字电力系统仿真器(advanced digital power system simulator, ADPSS)全电磁暂态仿真验证了暂态过电压问题优化效果。计算结果表明,暂态过电压和稳态低电压是制约张北地区新能源经特高压交流送出能力的主要因素,在新能源短路比较低的发电机组机端配置分布式小型调相机,可有效抑制暂态过电压问题,提高新能源整体送出能力。研究结果对电力系统规划、运行及国内同类新能源送出工程设计都具有较强的参考价值。

With the increasing proportion of new energy in power system, the safety and stability of large-scale new energy has become a common concern. Taking the 1 000 kV Zhangbei—Xiong’an UHVAC transmission line from the 10 million kilowatt new energy base in Zhangbei area as an example, this paper builds a PSASP electromechanical transient simulation model, which includes new energy model and distributed condenser model with low voltage crossing function. The paper analyzes the constraints of the new energy transmission capacity. And then the influence of different configuration schemes on short-circuit ratio of new energy and the suppression effect of transient overvoltage are studied. Finally, the optimization effect of transient overvoltage problem is verified by ADPSS all electromagnetic transient simulation. The results show that transient overvoltage and steady-state low voltage are the main factors restricting the transmission capacity of UHVAC line from new energy base. The distributed small-scale condenser is installed at the generator end with low short-circuit ratio of new energy, which can effectively restrain the transient overvoltage problem and improve the overall output capacity of new energy. The results of the study are of great reference value for planning, operation and design of the same kind of new energy delivery project in China.