Naslov
Earthing of previously unearthed medium voltage networks

Autori
Marušić, Ante ; Franković, Dubravko

Izvornik
WSEAS transactions on power systems (1790-5060) 1 (2005); 116-122

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
medium voltage network; isolated network; resonant earthing; earth-fault; recovery voltage

Sažetak
A large number of public utilities adopted the concept of isolated medium network operation. Increased cabling of previously overhead lines and construction of new cable feeders resulted in capacitive earth-fault currents increase. High earth-fault currents cause unacceptable touch potentials in vicinity of fault location and inadmissible potentials of neutral conductor in low voltage installations. Resonant earthing of isolated medium voltage networks has become an attractive way of earthing isolated networks. In fact, resonant earthed networks retain all advantages of isolated networks, especially, continuity of operation under sustained earth-fault conditions. Due to the fact that an adjustable inductance is connected to main HV/MV transformer’ s neutral point, through fault location only a small active component of the earth-fault current flows, thus causing no thermal stress to faulted equipment and preventing restriking faults i.e. intermittent overvoltages. The "tunable" inductance is adjusted to compensate network's ground capacitance. In this paper isolated and resonant earthed networks will be compared, and expressions for normal operating conditions and fault conditions will be derived.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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