Air Insulation 17.5kV Ring Main Unit (SM66)
Standards
IEC 62271-100 high voltage alternating current circuit breakers
IEC 62271-105: alternating current switch-fuse Combination
IEC 62271-102: alternating current disconnectors and earthing switches
IEC 62271-200 A.C. metal enclosed switchgear and controlgear for rated voltage above 1 kV and up to and including 52 kV
IEC 62271-103 high voltage switches for rated voltage above 1 kV and less than 52 kV
IEC 60694: Common specifications for high-voltage switchgear and controlgear standards
IEC 60265-1 Switches for rated voltages above 1 kV and less than 52 kV
IEC 60529: Degrees of protection provided by enclosures (IP Code)
Service environment:
a) Air temperature:Maximum temperature: +40℃; Minimum temperature:-25℃
b) Humidity:Monthly average humidity 95%; Daily average humidity 90% .
c) Altitude above sea level:Maximum installation altitude: 2500m
d) Ambient air not apparently polluted by corrosive and flammable gas, vapor etc.
e) No frequent violent shake
Technical data
|
Item
|
Unit
|
Switch
|
Switch-fuse
|
Vacuum circuit-breaker
|
|
Rated voltage
|
kV
|
17.5
|
17.5
|
17.5
|
|
Power frequency withstand voltage
|
kV
|
38
|
38
|
38
|
|
Impulse withstand voltage
|
kV
|
95
|
95
|
95
|
|
Rated current
|
A
|
630
|
2001)
|
200
|
|
Breaking capacities:
|
|
|
|
|
|
active load
|
A
|
630
|
|
|
|
closed loop
|
A
|
630
|
|
|
|
off load cable charging
|
A
|
135
|
|
|
|
off load transformer
|
A
|
|
20
|
|
|
earth fault
|
A
|
150
|
|
|
|
earth fault cable charging
|
A
|
87
|
|
|
|
short-circuit breaking current
|
kA
|
|
see
|
16
|
|
Making capacity
|
kA
|
40
|
see
|
40
|
|
Short time current 0,5 sec
|
kA
|
|
|
16
|
|
Short time current 1 sec
|
kA
|
|
|
16
|
|
Short time current 3 sec
|
kA
|
16
|
|
|
1) Depending on the current rating of the fuse-link
2) Limited by high voltage fuse-links
SafeClad gas insulated ring main unit is for the secondary distribution network 11/17.5/24/36 kV. It is a completely sealed system with a stainless steel tank containing all live parts and switching functions. A sealed steel tank with constant atmospheric conditions ensures a high level of reliability as well as personnel safety and a virtually maintenance-free system.
It offers a choice of either switch-fuse combination or circuit-breaker with relay for protection of the transformer. SafeRing can be supplied with an integrated remote control and monitoring unit.
