Analysis on Regional Load Margin of Guangdong Power Grid

By use of regional load margin analysis method the static voltage stability of Guangdong Power Grid (GDPG) under summer-heavy operation mode in 2005 is studied. The regional active load margin index is defined and the sensitivity analysis for the influence of N?1 outages of 500 kV AC transmission lines and the HVDC system outages on this index is carried out. Analysis results show that: (A) the regional load margin is suitable to be the security index for static voltage stability; (B) the load margins of the Pearl River Delta in GDPG with heavy load and eastern GDPG are small, therefore they are the weak region of voltage security; (C) the key transmission lines which mostly influence load margin are the tie-lines which feed power from Guangxi Power Grid to GDPG and the following transmission lines within GDPG: from Shajiao to Pengcheng, from Ling’ao to Dongguan and from Dongguan to Huizhou; (D) the outages of HVDC system evidently decrease the load margin, in which the line from Guizhou to Guangdong plays a primary part and the line from Tianshengqiao to Guangdong and the one from Three Gorges to Guangdong play a secondary part. Therefore the operation personnel should pay special attention to the monitoring of above-mentioned key lines and weak regions.