HT & LV cables side by side - voltage effects

[Andiri]

1) How do I determine the minimum distance between 2 parallel cable runs of different voltage, eg. 11kV and 380V?

2) How does the one voltage effect the other, and why?

 

[bobziva]

Standards and Rules are provided to maximize a minimum distance between communication and power cables. The reason for that is to mimnimize a electromagnetic induction, to save comm. cables from that induction. Before fiberoptic cables influence of that induction was very strong ( noise on the communication). Today is much better.
For metal sheet power cables, back to back installation is normal, that induction probably exists but is not making a big problem.
Generally, if you have a space put medium voltage power cables together (15, 25 kV etc)and 380 Volts with control and instrumentation cables.

 

[sdlloyd]

When considering the minimum distance between cables the following is important:

Maintaining the cable ratings (ampacity): If the cables are buried then this is normally a thermal consideration. The cables being kept adequately separated to allow heat to flow away from the cables.

Mutual Induction: Magnetic linkage between cables will produce mutully induced voltages and currents. see thread238-59910 It is normal for higher voltage cables to be kept at a distance from LV cables (even if only by depth), there are normally national rules govering the separation of cable voltages in public land. HV cables are normally buried deeper than LV cables in separate reserves (corridores/wayleaves).

Available space: Within reason, the further the separation the better.

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