We use ungrounded DC system (220V/110V) for control and
protection system in substations etc. Suppose we have long
2 core DC cables running from our DCDB in control room to
the load (length of around 2 to 3 km). Do we need to
protect these long DC cables from earth leakages or not? If
yes how?
Answer Posted / k.prakashchandra
Normally dc earth fault locater is employed. If one polarity
shows earth fault there is nothing to panic.Heavy fault
current occurs if the other polarity also develops fault. If
tripping is provided ,the protection may get lost.
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