metering CT saturation

[tsknan]

whether Metering CT can be saturated with injection of DC by using diodes? what is the Direct current required in primary to saturate CT?how long this current can pass through CT without affecting CT life?

 

[scottf]

Saturation point of a CT is completely dependent on the particular design (i.e. core size, core material, number of turns).

DC offset can cause saturation.

If the primary current is pure DC, then no transformation occurs and there is no risk for damage.

If the primary current is AC with a DC offset or components, then saturation can occur. As a very general statement, metering core heat losses are normally pretty low and operation in saturation for certain periods of time will likely not cause damage.

 

[tsknan]

thanks,
can you provide me some more details?
or some related links of documents related with this,
i required this for some investgation purpose ogf energy theft in 33KV level by suspected DC injection,
one 50MVA transformer failed due to this(suspect only,no details) any practcal circuits available for this?
explain in detail
tsknan