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Ring Main Units

Ring Main Units

Ring Main Units - switches can be freely assembled in a completely sealed tank filled with SF6 gas, which could be both manual and motor operation. FTU/RTU is operational. Up to 4 to 7 switches can be assembled. Load break switches, circuit breakers and fuse-switch combination can be freely assembled. Cables exit from front side or rear side of the device. Operating is controlled by spring mechanism; permanent electromagnetic protection is optional configuration. Circuit breaker can adopt self-powered micro-computing relay or normal micro-computing protection relay.

We can supply Special specifications according to customers' requests.

 

Technical Data

Item

C - unit

F - unit

V- unit

load-break switch

load-break switch +

fuse combination

vacuum circuit-breaker

earth switch/disconnector

Rated voltage   kV

12 / 24

12 / 24

12 / 24

12 / 24

Power frequency

withstand voltage kV

42 / 50

42 / 50

42 / 50

42 / 50

Lightning impulse

withstand voltage kV

95 / 125

95 / 125

95 / 125

95 / 125

Rated current   A

630 / 630

See 1)

630 (1250/ 630(1250)


Rated closed-circuit

breaking current    A

630 / 630




Rated cable-charging

current  A

135 / 135




Breaking current under

earth-fault conditions  A

200/150




Cable breaking current under earth-fault conditions  A

115/87




Rated short-circuit

breaking current  kA


See 2)

20/16


Rated short-circuit

making current  kA

63/52.5

See 2)

50/40

50/40

Rated short-time

withstand current

kA  3s

20/20


20/16

20/16

Mechanical life

5000

3000

5000

2000

Note1): dependent to fuse rated current          Note2): dependent to fuse

IAC: 20kA 1s

Degree of protection: IP67

Annual Leakage rate: ≤0.25%