Investigation of Zero-Sequence Current in Medium and High Voltage Cable Systems

The problem of large zero-sequence current (I
ZS
) in cable bus duct systems is not new; the question is what impacts its size. This paper investigates a I
ZS
at a practical site where a large I
ZS
is discovered in a power cable system (at the Mit-Faris station of transformers). As a result, this phenomenon will be examined and discussed in this paper. This type of study is simulated and analysed using ATPDraw. Analyses and discussions of the impact of sheath cross bonding are also included. The results show that the zero I
ZS
situation corresponds to the point or axial symmetry in the two parallel circuits. However, even with the symmetrical arrangement, a four-circuit system does not produce a significant decrease. Also, the results indicate that a minimum
$(\mathbf{I}_{\mathbf{ZS}}/\mathbf{I}_{\mathbf{load}})$
, ratio of 4 % is achievable. According to the findings, I
ZS
were cycling across separate circuits in the cable system and were created by induction between phases in the same cable route.