Outdoor Ring Main Unit

Description

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 Beierbian Group 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

Technical data

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 filling. 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.

Complete outline drawing

A.No-extensible type

B.Extensible type

Note:
Details demission pls consult with our engineer to ask drawings.

Standard UNIT configures

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

Standard Combination configures

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.

Internal structure

1.Lifting lugs;2.Stainless steel enclosure;3.Cable pillar;4.Cable front joint;5.Rear connrcted lightning arrester;6.CT;7Three position load break switch;8.Fuse tube;9.Earthing switch for fuse tube;10.Fuse tube plug;11.Insulator;12.Mechanism for load break switch;13.Live display;14.Mimic;15.SF6 Pressure gauge;16.Lock;17.Cable clip mouting plate;18.Base mounting frame;19.Circuit breaker+Disconnector;20.Mechanism for Circuit breaker;21.Mechanism for disconnector

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.