Technology of Lightning Protector for Low Voltagc Distribution System and Its Development
Liu Mingdong · Insulators and Surge Arresters · 2007
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 generation-surge 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.