典型高比例新能源地区电网采用柔性直流技术进行加强的方案设计方法

本文提出了典型高比例新能源地区电网采用柔性直流输电(VSC-HVDC)技术进行加强的方案设计方法和流程。结合高比例新能源地区电网的特征,首先分析了制约其安全稳定运行的3个主要因素;然后从加强电网安全稳定性的角度,以云南楚雄电网为例设计了采用VSC-HVDC的两种加强方案,进一步提炼出了高比例新能源地区电网采用VSC-HVDC进行加强的选址和定容方法,并且归纳了3个衡量VSC-HVDC加强方案优劣的技术性指标,分别是线路负载率、电压水平以及VSC接入点强度。计算结果表明,按照所提的方案设计方法,两种VSC-HVDC加强方案均能将过载严重的线路负载率降低至90%以下,很好地解决了新能源大发方式下电磁环网的线路过载问题;此外,采用VSC-HVDC技术对地区电网进行加强后,故障期间楚雄地区关键节点的电压水平提升了10%~19%,有效地提升了系统的电压水平。

Design Method for Reinforcement Scheme of Typical Regional Power Grid with High Proportion of Renewable Energy Using VSC-HVDC Technology

A design method for the reinforcement scheme of the typical regional power grid with high proportion of renewable energy using VSC-HVDC technology is proposed in this paper. Considering the characteristics of the regional power grid with high proportion of renewable energy,three main factorsrestricting its safe and stable operation is analyzed firstly. Then from the perspective of enhancing the safe and stable operation of power grids, two VSC- HVDC reinforcement schemes are designed by taking Chuxiong Power Grid in Yunnan as an example. A method to determine the location and capacity of the VSC-HVDC system in the regional power grid with high proportion of renewable energy is proposed further and three technical indexes to evaluate the VSC-HVDC schemes,namely line load rate, voltage level and the strength of the VSC connection point are summarized. It is shown by the calculation resultthat following the proposed design methodology, the two VSC-HVDC schemes can reduce the line load rate of those lines with severe overload problems to less than 90% ,which is a good solution to the line overload problem of the electromagnetic loop networks with high generation of renewable energy;W ith the VSC- HVDC technology, the voltage level of key buses in Chuxiong area is increased by 10% ~19% during the faulted period,effectively increasing the voltage level of the system.