Mutual Coupling Compensation Techniques Used for Distance Protection of Parallel Lines

Energies

Noel Barry¹  Joe Connell¹  Michael O Donovan¹  Eoin Cowhey² 

[1] Department of Electrical and Electronic, Munster Technological University, Bishopstown, T12 P928 Cork, Ireland;Electricity Supply Board, Rosbrien Rd, V94 A5D2 Limerick, Ireland;

关键词: mutual coupling;    earth fault;    distance protection;    mutual compensation;   

DOI  :  10.3390/en14071982

来源: DOAJ

【 摘 要 】

When a distance relay protects a transmission line located on a dual circuit tower, a coupling effect will occur between the two circuits. Transposition of the circuits can reduce the mutual impedances, but this does not cater to the zero-sequence mutual coupling impedance during earth faults. As a result, the impedance measured by a distance relay under phase-to-earth fault conditions in these circumstances will not represent the correct impedance to the fault point unless these effects are taken into account. On multi-circuit lines, primarily if they operate in parallel, a zero-sequence mutual coupling should be considered when calculating settings for distance protection function. A 220 kV parallel line sharing the same tower was analysed using DigSilent Power Factory in the simulations. Phase-to-earth faults in different configurations were analysed on this system, and the reach of the protection relay was then estimated for operation. The results confirm how a protection relay can overreach and underreach in a distance protection scheme due to the influence of mutual coupling.

【 授权许可】

Unknown