Identifikace obrazců částečných výbojů VN izolačních systémů

Abstract

Covered conductors are alternative to aluminum core steel reinforced medium voltage overhead lines in a forested terrain. The main reason for the use is their high reliability. It is given by the XLPE insulation system, when in case of contact of phases with surrounding vegetation, there is no short-circuit current. However, the disadvantage of the covered conductors operation is the problematic detection of faults, when the covered conductor is ruptured due to atmospheric overvoltage or is damaged due to destructive degradation of the insulation system. The fault detection is problematic because of the very small value of the fault current. The starting element of the standard digital relay protection cannot detect this type of faults. This thesis contains description and results of a new fault detection system for overhead lines with covered conductors. The method of insulation fault determination is based on partial discharges activity detection.