36kV --245 kV Dry Type Current Transformer

LGB –Series,
Structure
The CT is an organic composite insulation structure, consisting of winding assembly, silastic umbrella, base and so on. The winding assembly includes primary winding which forms a “U” shape and 2~6 groups of secondary windings. The principal insulation is condenser type. And it adopts electric-screen uniform structure. The insulation is fully bandaged by machine automatically. The sheath of winding assembly is using heat-shrinkable materials. The silastic umbrella bonded outside can separate it from the outer environment. It has high electrical intensity and low dielectric loss rate and partial discharge through optimum design and strict technological process. The primary winding includes 1~2 groups for essay changing the current ratio by serial and parallel. The secondary windings with tapping wind on the ring core which is with annealed high quality grain oriented silicon steel (or AMD chips). The terminal box is installed on the base, from which the secondary leads are drawn and the end screen lead is drawn alone.

Advantages
1. Non-oil, non-porcelain, non-gas, working under atmospheric pressure, no leakage, no combustion and explosion, no environment pollution, it is suitable for unguarded substation.
2. Low partial discharge and dielectric loss, stable performance.
3. It has good partial discharge characteristics. As the voltage increased and the time passed, the starting voltage of partial discharge increased, partial discharge decreased accordingly.
4. Primary winding, secondary winding and leads are waterproof structure. It doesn’t have high requirement for sealing of the products.
5. The external insulation adopts silastic umbrella to improve the flashover sewage voltage significantly.
6. Small volume, light weight, easy installation.
7. Easy maintenance. You only need to monitor the electric capacity regularly.

Main technical data and performance
Standard: Comply with IEC60044-1:2003 or similar standards
Highest system voltage: 36--245kV
Raetd primary current: 5~3000A
Rated secondary current: 1A or 5A
Accuracy class of the windings for measurement: 0.2S, 0.2, 0.5S, 0.5
Accuracy class of the windings for protect: 5P, 10P, 5PR, 10PR, TPY, TPS, TPX, TPZ
No. of the secondary windings：1～8个
Rated output：5～50VA
Security factor of the instrument(Fs)：5、10
Accuracy limit coefficient：5、10、15、20、25、30、40
Temperature rise limit: the max temperature rise should not be more than 75K.
Rated short-time thermal current (Ith) and dynamic stable current (Idyn):
th=31.5kA(4S); Idyn=80kA(peak)  or Ith=50kA（3S）； Idyn =125 kA (peak)