CT grounding
CT grounding
(OP)
Quick question...
Does it matter which leg of a transformer is grounded?
Since the current "flip-flops" back and forth 120 times a sec (60hz) I would not think so.
I am not an expert though...
Regards,
TULUM
Does it matter which leg of a transformer is grounded?
Since the current "flip-flops" back and forth 120 times a sec (60hz) I would not think so.
I am not an expert though...
Regards,
TULUM






RE: CT grounding
RE: CT grounding
So if we are consistant there should be no headaches...
Regards,
TULUM
RE: CT grounding
Agree with davidbeach. Never earth both side of the CT simultaneously. This effectively shorts out the CT load. With threephase systems, the CT's are commonly shorted at the neutral point. Again only earth at one point. The idea of earthing after all is to prevent the secondary wiring insulation being stressed beyond its intended design insulation voltage.
Regards.
RE: CT grounding
To prevent secondary circuits from attaining dangerously high potential to ground, these circuits are to be grounded. Connect either S1 terminal or S2 terminal to ground.
For protective relays, ground the terminal that is the nearest to the protected objects.
For meters and instruments, ground the terminal that is the nearest to the consumer.
When metering instruments and protective relays are on the same winding, the protective relay determines the point to be grounded.
if there are taps on the secondary winding which are not used, then they must be left open.
If more than one current transformer are galvanic connected togher they shall be grounded at one point only (e.g. differential protection)
If cores are not used in a current transformer they must be short-circuited between the highest ratio taps and shall be grounded
It is dangerous to open the secondary circuit when the CT is in operation. High voltages will be induced.
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RE: CT grounding
Is there any harm in just always grounding the x1 terminal of the ct? We sometimes ground the x1 and we sometimes ground the x2... However, since ct's such as the hammond CT200 comes with leads where the white is the x1 and the black is the x2... if we ground the white it stays consistant with what we do on PT's.
No electrical logic, just easy for the guys in the field
Any thoughts?
Regards,
TULUM
RE: CT grounding
Sometimes in 3ø applications it is necessary to use X2 as common. In this situation you cannot ground X1.
RE: CT grounding
RE: CT grounding
RE: CT grounding
RE: CT grounding