ARRESTERS - LIVE INSURANCE OF THE GRID TRENDS DEVELOPMENTS: LINE SURGE ARRESTERS - A BUNCH OF ADVANTAGES - (PPT)

摘要

Surge arresters installed on a transmission line are termed Line Surge Arresters (LSA). But not only is the location of installation the decisive criteria, it is the purpose of the installation: These arresters are commonly used to address lightning- or switching- related phenomena with the intent to improve the overall reliability of transmission lines. In contrary to the purpose of station arrester installation LSAs task is not the protection of local insulation systems, like bushings, cable terminations, electrical machines etc. LSAs must prevent uncontrolled flashovers of transmission line insulators in order to prevent earth faults and short circuits "inside" of the system component "transmission line". Line arresters can improve system reliability by reducing the multi-phase and multi-circuit line outage rates, or be used to help control switching overvoltages on EHV transmission lines rather than using closing resistors or controlled closing schemes. This application of LSA can be used for all system voltages including EHV systems. There are many ways to group LSAs, according to system voltage, the major problem on the line, housing types etc. But the most important is the difference between LSA without gap (gapless line arresters) and externally gapped line arresters, the EGLAs. Both types are not innovations, well known for years now and EGLAs have quite a long history especially in East Asia. The new IEC 60099-8, which has been finally released at the beginning of the 2011, is the first global and specific EGLA-standard. This is a remarkable step forward and brings both challenges and opportunities for users as well as for the manufacturers of this type of arresters. Both NGLA and EGLA line arrester types have different features making them more suitable for certain applications.