Open-Phase Operating Modes in High Voltage Distribution Networks

Abstract

The open-phase operation modes which arise during the breakdowns of the wires of overhead power transmission lines, incomplete phase commutations, broken contacts, and for other reasons are not always accompanied by high emergency currents sufficient for the operation of relay protection. Experience of operation shows that in complex electric networks at wire breakage of transmission lines there are operating modes that lead to non-selective operation of relay protection and excessive power cuts. The analysis of processes occurring in open-phase modes, determining dependencies of currents from various factors, and the reaction of relay protection is considered in the article.