Design and Application of EHV Disconnecting Switches

Technical data, accumulated while designing and testing EHV (extra-high-voltage) disconnecting switches, are being presented as an application guide in establishing EHV switch insulation coordination. Dielectric characteristics of large single and large double switch gaps are included for making comparisons between single-break and double-break switches. The subject of EHV switch open gap insulation coordination is reviewed in rather complete detail. Design criteria and test data are submitted, covering a 500-kV switch employing a variety of EHV insulators. Attention is called to several subjects requiring action and resolution by electrical-power-industry standardizing organizations.