1) The OMR is a ring main unit for 12/24kV secondary distribution networks that comes in 10 configurations and can be mounted on transformers or standalone. 2) It uses SF6 gas insulation and switching within a welded stainless steel tank to provide a sealed for life system with high reliability and safety. 3) Standard unit configurations include non-extensible, extensible, and combinations that can be customized and equipped with indicators, protection relays, and bushings.

1. Outdoor Gas Insulated RMU
Catalogue
OMR-12 kV /17.5kV /24kV
2012/8
Wenzhou Rockwill Electric Co.,Ltd.
Best solution for your power!

2. General
OMR is a ring main unit for the secondary distribution network. OMR can be supplied in 10
different configurations suitable for mostswitching applications in 12/24 kV distribution
networks. The Unit can be mounted to the smallest distribution transformer or be sited in a free
standing format.
It is extendable and combined with Rockwell own developed technology concept, which is
flexible, modular compact switchgear, they represent a complete solution for 12/24 kV
secondary distribution networks. OMR have identical user interfaces.
OMR 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.
The OMR concept offers a choice of either switch-fuse combination or circuit-breaker with
relay for protection of the transformer. OMR can be supplied with an integrated remote control
and monitoring unit.
This product is in conformity with the standards:
Iec62271-200, IEC60420, GB/T11022, GB3804,GB3906
Service environment
a) Air temperature:Maximum temperature: +45℃; Minimum temperature:-20℃
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

3. Enclosure
OMR use SF6–gas (Sulphur hexafluoride)
as insulation and quenching medium.
The SF6 is contained in a welded stainless
steel tank, which is sealed for life.
The pressure system is defined as a sealed
for life system with an operating life time
exceeding 30 years. The leakage rate is less
than 0,1% per year.
In order to ensure a reliable and tight welding,
all welding work is carried out by computer
controlled robots.
Electrical and mechanical bushings
penetrating the tank are clamped and sealed
to the tank by high quality O-rings.
The mechanical bushing has in addition a
rotating shaft which connects the shaft of the
switch to the corresponding shaft of the
mechanism. The rotating shaft is sealed by a
double set of gas seals.
All SF6-tanks have to pass a leakage test
before gas fill-
ing. Leakage test and gas filling are done
inside a vacuum chamber. The first step in
the leakage test is to evacuate all air inside
both SF6-tank and vacuum chamber
simultaneously. Then the SF6-tank is filled
with Helium. Due to the character-istics of
Helium this test will detect all possible
leakages. If the SF6-tank passes this test, the
Helium will be evacuated and replaced by
SF6.
The SF6-tank has a degree of protection of
IP67 and can be immersed into water and still
maintain all functions in a satis-factory way.

4. Complete outline drawing
A.No-extensible type
B.Extensible type
Note:
Details demission pls consult with our engineer to ask drawings.

5. Standard UNIT configures
Extensible Standard Unit C Extensible Standard Unit V
Extensible Standard Unit F eqv unit DF Extensible Standard Unit M
Note:
1, All the standard is optional to be equipped with Indicator, PT, Relay protection.
2, Extension bushing can be used for cable feeder or cable incoming.
Standard Combination configures
Left extensible Combination CC Left extensible Combination CV

6. Standard Combination configures
Non-extensible combination CCV Non-extensible combination CCB
Extensible Combination CC Extensible Combination CV
Extensible combination CCV Extensible combination CCB
Note:
1, All the standard is optional to be equipped with Indicator, PT, Relay protection.
2, Extension bushing can be used for cable feeder or cable incoming.
3, Extensible combination is provided by united with suitable unit.,
For example: CCV+F+CCB+M+….; Customized make is acceptable.

7. Internal structure
CCF CCV

8. Main technical specifications
No Item Unit Load Break Switch Circuit Breaker
1 Rated voltage kV 12/17.5 24 12/17.5 24
2 Rated current A 630
3 Rated frequency Hz 50/60
4 1min Power frequency withstand
voltage
kV
45 55 45 55
5 Lightning impulse withstand voltage kV 95 125/150 95 125/150
6 Rated transfer current A 1700 1400
7 Rated active load and close circuit
breaking current
A 630
8 Rated cable charge breaking current A 50&10
9 Rated short circuit breaking current kA 20 16
10 Rated short circuit making current
(peak)
kA 63 50 63 50
11 Short time (2s) withstand current, load
switch/earth
kA 25/20 20/20 25/20 20/20
12 Rated withstand current (peak) kA 63 50 63 50
13
Mechanism life
Tim
es
3000 10000 3000

9. Protection Relays:
RP260 relay is intended to be used for the
selective short-circuit and earth-fault
protection of feeders in second-ary
distribution networks and for protection of
transformers in utilities and industries. This
relay has dual mode of earth-fault
measurement - internal vector summation or
external CBCT input. Functions are easy to
set up by using the dip-switches.
Cable bushings and cable clips：
The connection of the HV-cables is made by
cable bushings. The bushings are made of
cast resin epoxy with moulded-in conductors.
In addition, a screen is moulded in to control
the electrical field and is also used as the
main capacitor supply-ing the voltage
indicating systems.
Up-to-date production facilities and highly
advanced robots and test equipment ensure
the high quality required for each single
device.
A very high number of units have been
installed worldwide
in distribution networks, power stations and
industrial com-plexes.
Used together with full-screened connectors,
an ideal solution for areas with humidity or
condensation problems is achieved. .
Fault passage indicator
A fault passage indicator may be delivered as
an option to the OMR switchgear. The
indicator is usually placed in the front panel of
the switchgear. It makes it possible to de-tect
any faults, including short circuits, earth-faults
and short current direction, and makes it
easier to locate any fault.