Leakage Voltage in Control Cables

What about SIS

Dear Sir

Kindly let me know the following :

1)Is the armour grounded on both sides or at one side or not at all grounded ?The armour shall be grounded at one side only( either the swgr side or the DCS/PLC side) to eliminate circulating currents (if any).

2)There cld be some sort of induction effect in the spare core due to the flow of current in the live cores.

3)What is the seperation being maintained between the power cables (HV or LV ??) ?Min 300 mm of clear seperation is recommended.

4)The length should not matter because signals are transmitted beyond one km also without any distortion and any such freak phenomenon.

5)Pl check the brand of cables being used in yr earlier plant and the ones being used for the present site.It might be related ( and specific to ) to certain brand of cables.In which case the issue needs to be discussed with the cable manufacturer along with the test reports/inspection reports.Pl let me know the value of IR value u are able to get for these control cables.

6)Finally u are required to scrutinise the switchgear scheme thoroughly ( literally follow the current/signal) ,the involved wiring,aux contactors,their contacts,the control transformer (and its grounding??).The problem should, should surface.

6)If nothing works u may consider grounding the spare cores as well along with the armour.AND then check for any abnormal behaviour.

Request for a feedback.

Regards

Ravipra