1 000 kV特高压南阳变电站110 kV侧低压无功补偿设备与传统超高压变电站的低压无功补偿设备相比，在设备原理、设备容量、接线方式、保护原理和控制方案方面存在较多的特殊性和创新性。介绍了大容量并联电容器组双桥差保护接线的方案；110 kV新型负荷开关的应用使110 kV系统的无功设备保护跳闸采用2级出口，失灵保护采用的2级失灵方案；母线死区故障采用特殊跳闸方案；特高压变电站站用变容量相对较小，针对电流互感器（current transformer, CT）配置、继电保护定值整定、系统调试等方面出现的新问题提出了解决方案。鉴于南阳站站用电系统接线方式的特殊性，提出了110   kV站用变差动保护范围的优化方案。

The 110 kV low voltage reactive power compensation equipment in 1 000 kV Nanyang substation has some specific characteristics and innovation compared with that in traditional EHV substation, such as the equipment principle, equipment capacity, connection mode, protection principle and control scheme. This paper introduces the connection scheme of double H type protection for large-capacity shunt capacitance bank. Because of the application of new 110 kV load breaker switch (LBS), both the trip protection of 110 kV reactive power and failure protection are level 2, and the particular trip scheme is used for bus dead zone fault. Due to the small auxiliary transformer capacity of UHV substation, some new problems are still existed in current transformer (CT) configuration, fixed value setting of relay protection and system testing, and correspondingly some solutions are proposed. Because of the particularity of connection mode of auxiliary power system in Nanyang substation, an optimization scheme on the scope of transformer current differential protection is put forward.