Easy Qn- Circulating Currents in Utility Systems ?!

[Samuel2500]

Hey all,

Just quickly - I understand you can get circulating currents between distribution substations and i was wondering how these occur or caused by?

 

[PHovnanian]

It depends on how the distribution systems are configured. Most distribution circuits I'm familiar with are radial circuits. They are not normally tied to circuits fed by other substation.

There are times when circuits from adacent substations will be tied in parallel. During line switching operations, for example.

If the turns ratios of the station transformers do not match perfectly, or if the regulators are set at different points, reactive circulating currents will travel around the loop, driven by the voltage difference caused by the ratio or voltage setting mismatch.