Current Transformer (PT)

General Particulars 11KV 33 KV
Highest System Voltage( H.S.V.) 12 KV ( r.m.s.) 36 KV (r.m.s.)
Power frequency dry/ wet withstand voltage on primary winding for one minute 28 KV ( r.m.s.) 70 KV ( r.m.s.)
Lightning Impulse withstand voltage (1.2 x 50 μs ) 75 KV ( r.m.s.) 170 KV ( r.m.s.)


Specific Particulars  
Rated Transformation Ratio As per customer requirement (in Amp.)
Rated Primary Current Upto 2000 Amp.
Rated Secondary Current 1 Amp.  5 Amp.  0.577 Amp.
Short Time Thermal Current (Ith) As per customer requirement.
In general CT is to be specified with STF of 100 for 1 Sec. or STC (lth) equal to the system fault level whichever is lower. KA ( r.m.s. )
Ith duration 0.5 to 3.0 Second
Short Time Dynamic Current 2.5 X Ith KA (Peak)
Number of Cores Upto 5 cores
Output Burden Upto 60VA, 0.8 pf Lagging
Accuracy Class For Metering : 
0.2S, 0.2, 0.5S, 0.5, 1.0 & 3.00. For Protection:                                                  
5P, 10P, 15P & PS
IAF, ALF, Knee Point Voltage, Exciting Current & Resistance As per customer requirement / Design Constraints
Type of construction Dead / Bottom Tank or Live / Top Tank