Economical Overvoltage Protection by Metal-Oxide Surge Arresters Integrated in High-Voltage AIS Disconnectors - Substation Integration, Design and Test Experience-

摘要

In high-voltage transmission systems instrument trans-formersrnand circuit-breakers are frequently damaged byrndirect multiple lightning strokes into the phase conduc-torsrnof overhead lines nearby a substation. These de-vicesrncan be protected by arresters at the line entrance.rnAn efficient and economical solution of a standard ar-resterrnintegrated into a standard disconnector is pre-sented,rnwhich allows to install the arrester withoutrnadditional space requirement. The new device has beenrnapplied in 245-kV- and 420-kV-systems so far. Only forrnthe 420-kV-system some modifications to the gradingrnring of the arrester had to be introduced. This paperrnreports on the requirements on the disconnector/arrester,rnthe realization and the investigations and tests per-formed.rnThe protection characteristic is demonstrated byrnEMTP calculations based on models derived from fullrnscale tests in the high-voltage laboratory.