40.5kV 126kV 252kV Dry Type Transformers

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.

        The main technical specification of dry type current transformer

Type		LGB-35W2	LGB-126W2	LGB-252W2
Rated frequency(Hz)		50
Polarity		negative
Rated vlotage (kV)		35	110	220
Maximum operation voltage(kV)		40.5	126	252
Power frequency withstand voltage(kV)		95	230	460
Lighting impluse withstand voltage(kV)		200	480	1050
Rated primary current(A)		150-3000	150-2500	300-3000
Rated secondary current(A)		5 or 1
Rated current ratio		2*150-2*1500/5(1)	2*150-2*1250/5(1)	2*300-2*2000/5(1)
Thermal stability current(3 s)(kA)		22-63	22-63	63
Rated dynamic stability current(kA)		57-160	57-160	160
Accuracy class	Measuring class	0.2,0.2S,0.5,0.5S
	Protective class	5P,10P	5P,10P	5P,10P
Measuring security factor		5,10 or without any requestion
Accuracy limit factor for protection		15-40
Windings combination		Random combination of measuring and protective coils from 2 to 4	Random combination of measuring and protective coils from 2 to 6	Random combination of measuring and protective coils from 4 to 8
Sea level altitude(m)		not exceed 2000
Ratio of the creepage distance(mm/kV)		16,25,31
Static allowerable load of the primary outlet terminal		4000N
Weight (kg)		165	260	650
Transportation weight(kg)		700kg/set(each three transformers)	1000kg/set(each three transformers)	2450kg/set(each three transformers)