MV arc suppression with faulted phase earthing and selective tripping on heavily asymmetric networks

The MV networks operated by ESB Networks (ESBN) exhibit very high levels of static and dynamic asymmetry. Historically, application of arc suppression to such networks was considered impractical or unsustainable. This paper outlines the trials and live earth fault tests that confirmed how modern techniques make arc suppression in such networks successful. Further, the addition of faulted phase earthing ensures that fault site conditions are optimised where tripping is not necessary. The scope of earth fault protection employed and techniques used for high efficiency fault location are outlined.