低压配电系统防雷产品技术及发展

Technology of Lightning Protector for Low Voltagc Distribution System and Its Development

综述了低压配电系统防雷产品发展的四个阶段,对其具有代表性的产品技术原理和技术性能以及优缺点进行了总结。第一代产品——空气间隙具有放电不稳定,放电具有延时效应,工频续流较大。第二代产品——阀式避雷器采用碳化硅电阻片,具有较明显的非线性特性,配合放电间隙可很好地限制间隙击穿后的工频续流,但放电分散性大,连续电涌冲击保护能力差,使用寿命短。第三代产品——金属氧化物避雷器具有更优良的非线性特性和更大的电涌吸收能力,还具有纳秒级的响应速度,以及优异的陡波响应特性等优点,但在小电流区具有明显的负电阻温度系数,对避雷器动作负载和老化不利。第四代产品——电涌保护器主要是采用新型材料多手段控制的间隙和氧化锌压敏电阻等为元件,同时对防雷产品的安装结构、自身安全和故障自检等方面提出了新的要求。

Four steps of lightning protector development for low voltage distribution system are summarized wirh presentation of representatve products, their principles, characteristics and behaviors. First generation-spark gap has unstable flashover performance, delayed effect and high following current. Second generation-valve type lightning arrester with silicone carbide resistors, have relatively apparent non-linear characteristics which can limit the following current of power frequency together with spark gaps after their flashover, but has quite large flashover deviation, poor protection capacity against repeated surges and short service life. Third generation-metal oxide surge arrester has super non-linear performance and large surge absorption capacity, response of nano-second speed and excellent steep front surge response performance, but it has apparent negative thermal coefficient for its resistivity in small current zone which is disadvantage for its operating duty and ageing. Forth generationsurge protection device comprises of multi-controlled gaps made of new material and zinc oxide varistors, for which new requirements are put forward for its arrangenent, security of itself and fault self-detection.