YSM6-12~24 Air-insulated RMU(Fixed Type)

YSM6-12/24  unit  type  SF6  RMU  with  SF6  load  switch  as  main  switch, for  whole  cabinet  is  suitable  for  electric  distribution automation and compact also expandable metal close switchgear. It characters in its simple structure, flexible operation, reliable interlocking and convenient installation etc., which can provide the satisfactory technical projects both for different application occasions and users. With the adoption of sensor technology and the protection relay up to date, plus the advanced technology and flexible assembly project.

C YSM6-12/24 unit type SF6 RMU can completely meet the requirement of continuously variable market. It can take self-produced SF6-  12/24 load break switch; Operational methods for the main switch inside ring main unit can be either manual or electric power driven. And it can meet the requirement of "Four Controls" when matched with FTU and RTU.

Selection

Operating conditions

1.  Air temperature: Maximum temperature: +40℃; Minimum temperature:-5℃

2.  Humidity: Monthly average humidity 95%; Daily average humidity 90% .

3.  Altitude above sea level: Maximum installation altitude: 2000m

4.  Ambient air not apparently polluted by corrosive and flammable gas, vapor etc.

5.  No frequent violent shake

Features

1. Incoming unit with switch disconnector(Load break switch) schemas With other extra components optional Outgoing unit with

2. Fuse-switch protection schemas

3. With other extra components optional Incoming/outgoing circuit breaker protection schemas With other extra components

4. optional MV metering schemas

5. With other extra components optional Casings (Bus bar Panel) schemasWith other extra components optional

6. Others

Technical data

NO.	Items	Unit	Parameter
1	Rated voltage	kV	12	24
2	Rated frequency	Hz	50/60
3	Rated current	A	630/800
4	1min Power frequency withstand voltage	kV	48	60
5	Lightning impulse withstand voltage	kV	75	125/150
6	Rated short circuit breaking current (peak)	kA	80	63
7	Rated active load/close circuit breaking current	A	63	50
8	Rated transferring current	A	1700	1200
9	Rated short circuit making current (peak)	kA	80	63
10	Rated cable(line) charging breaking current	A	50 and 10
11	Cable charge breaking current in earthing fault	A	20	20
12	Rated withstand current (peak)	kA	80	63
13	Short time withstand current (2s)	kA	31.5	25
14	Mechanism life	times	2000

Note: For short circuit breaking and peak current is based on Fuse plus combination.

For distribution switchboard schema

1. Switch disconnector

2. Fuse-switch protection

3. Circuit-breaker protection

4. MV metering

5. Casings (Bus bar Panel)

2. Fuse-switch protection

 

 

5 parts for the unit type SF6 ring main unit:

 

1. switch cubicle switch-disconnector and earthing switch in an enclosure filled    with SF6 and satisfying “sealed pressure system ” requirements.

 

2. bus-bar cubicle all in the same horizontal plane, thus enabling later switchboard extensions and connection to existing equipment.

 

3.  connection cubicle accessible through front, connection to the lower switch- disconnector and earthing switch terminals (IM cubicles) or the lower fuse-     holders ( PM and QM cubicles). This compartment is also equipped with an

 

earthing switch downstream from the MV fuses for the protection units.

 

4. operation mechanism, interlocking contains the elements used to operate the switchdisconnector and earthing switch and actuate the corresponding

 

indications (positive break).

 

5. Low voltage cubicle (upper & lower enclosure structure) installation of a

 

terminal block (if motor option installed), LV fuses and compact relay devices. If more space is required, an additional enclosure may be added on top of the

 

cubicle.

 

6. Optional switch cubicles (IM) can also be fitted with: control motorisation;

 

surge arrestors.

 

 

 

The three-phase rotary contact is installed in a gas chamber filled with SF6 gas and the relative pressure is 0.4bars. It has excellent operation performance with safety and reliability.

● Tightness:

The air chamber is filled with SF6 gas, which meets the standard requirements of "closed pressure system ", and the sealing performance has been checked and

inspected in the factory.

● Operational Safety:

1. The switch has three positions of "closed ", "open" and "grounded ", and has a

locking function to prevent accidental operation. The contact is driven to rotate by

the spring energy storage mechanism, which is not affected by human operation factors.

2. Has "break " and isolation functions.

3. The short-circuit making capacity of the SF6 grounding switch meets the standard requirements.

4. In the event of an accident, the pressure drops after the overpressured SF6 gas breaks through the safety diaphragm, and the gas will directly be sprayed into the back of the cabinet for safety.

Breaking Principle:

SF6 gas has excellent arc extinguishing performance. When the switch is opened, the relative movement between the arc and the gas will extinguish the arc. When the moving and static contacts are separated, the arc appears in the electromagnetic field generated by the permanent magnet, and the arc is

elongated and extinguished when the current crosses zero by SF6 gas. The distance between the moving and static contacts is sufficient to withstand the recovery overvoltage. The system is simple and reliable, with minimal contact wear and long electrical life.

Fig 2) Whole Load break switch outline