±1100kV特高压直流送受端接入系统方案研究

A Study on System Connection Schemes for ±1100 kV UHVDC Sending and Receiving Ends

针对我国首个±1100 k V特高压直流工程(准东—皖南),研究了直流送受端接入系统方案。首先,对于直流送端系统,考虑直流再启动、闭锁等故障对电网的影响,采用直流安全稳定计算标准,从频率和电压稳定性角度研究送端换流站孤岛接入和联网接入2种方式的可行性。然后,对于直流受端系统,从提高多馈入短路比、抑制短路电流、平衡潮流分布3个层次,研究受端换流站单层接入500 k V、单层接入1000k V、分层接入1000 k V/500 k V这3种方式的可行性。最后,从受端换流站近区网架结构、接入通道选择等多角度研究并提出了换流站的系统接入网架方案。

System connection schemes of sending and receiving ends in the first ±1100 k V UHVDC project（Zhundong-Wannan） are analyzed in this paper. Firstly, for sending end, considering influence of DC recovery and DC blocking fault on power grids, feasibility of two connection modes（isolated and grid-connected operating modes） is discussed from perspective of frequency/voltage stability with DC security and stability calculation specification. Then for receiving end, from aspects of increasing multi-infeed short circuit ratio（MISCR）, reducing short-circuit current and balancing power flow distribution, feasibility of 500 k V single-layer connection, 1000 k V single-layer connection and 1000 k V/500 k V double-layer connection are studied respectively. Lastly, from perspective of grid topology of converter station connection and options for transmission channel in receiving end, etc, connection scheme of converter station is presented.