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01
Air Insulated Ring Main Units SM66-40.5kV
General
SM66 unit type SF6 ring net cabinet 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, SM66 unit type SF6 ring net cabinet can completely meet the requirement of continuously variable market. It can take self-produced RLS-40.5 load switch or SFG type SF6 load
switch by ABB; also according to user's demand can be assembled with the internationally top-ranking RCB series vacuum circuit breaker with permanent magnetic mechanism made by AREVA or HD4
type SF6 circuit breaker made by AREVA or HD4 type SF6 circuit breaker made by ABB or with our VS1-12 type vacuum circuit breaker with permanent magnetic mechanism. 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.
Service environment
a) Air temperature: Maximum temperature: +40℃; Minimum temperature:-15℃
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
Main technical specifications
| No | Item | Unit | Parameter | ||
| 1 | Rated voltage | kV | 36 | 40.5 | |
| 2 | Rated frequency | Hz | 50/60 | ||
| 3 | Rated current | A | 630/800 | ||
| 4 | 1min Power frequency withstand voltage | wet | kV | 70 | 95 |
| dry | kV | 80 | 110 | ||
| 5 | Lightning impulse withstand voltage | kV | 170 | 185 | |
| 6 | Rated short circuit breaking current (peak) | kA | 195 | 215 | |
| 7 | Rated active load and close circuit breaking current | A | 400/630 | ||
| 8 | Rated transferring current | A | 1200 | 1000 | |
| 9 | Rated short circuit making current (peak) | kA | 63 | 63 | |
| 10 | Rated cable offload | A | 50 | ||
| 11 | Transformer offload | A | 16 | ||
| 12 | Rated withstand current (peak) | kA | 63 | ||
| 13 | Short time withstand current (2s) | kA | 25 | ||
| 14 | Mechanism life | times | 2000 | 2000 | |
Note: For short circuit breaking and peak current is based on Fuse plus combination.
Structure & Basic Components of Ring Main Unit
Units for all functions
Field for application
The SM66 is made up of modular units containing fixed or withdrawable metal-enclosed SF6 switchgear, using sulphur hexafluoride (SF6) or vacuum:
1) switch-disconnector;
2) LNR, SF1 SF6 circuit breaker, UK36 vacuum circuit breaker;
3) JZ-40.5, or Rollarc 400 or 400 D contactor;
4) disconnector.
SM66 units are used for the MV section in MV/LV transformer substations in public
distribution systems and MV consumer or distribution substations up to 40.5 kV.
Operating conditions
SM66 units are designed for indoor installations (IP2XC).
Their compact dimensions are:
1) 800 mm to 1200 mm wide;
2) 2250 mm high;
3) 1400 mm deep …
this makes for easy installation in small rooms or prefabricated substations. Cables are connected via the front.
All control functions are centralised on a front plate, thus simplifying operation.The units maybe equipped with a number of accessories (relays, toroids, instrument transformers, surge arrestor, telecontrol, etc.).
Standards
SM66 units meet all the following recommendations, standards and specifications:
1) recommendations IEC:
60694: Common specifications for high-voltage switchgear and controlgear standards.
62271-200: A.C. metal-enclosed switchgear and controlgear for rated voltage above 1kV and up to including 52 kV.
60265: High voltage switches for rated voltages of 52 kV and above. 62271-105: High voltage alternating current switch-fuse combinations.
60255: Electrical relays.
62271-100: High-voltage alternating current circuit breakers.
62271-102: High-voltage alternating current disconnectors and earthing switches.
2) UTE standards:
NFC 13. 100: Consumer substation installed inside a building and fed by a second category voltage public distribution system.
NFC 13.200: High voltage electrical installations requirements.
NFC 64. 130: High voltage switches for rated voltage above 1kV and less than 52 kV.
NFC 64. 160: Alternating current disconnectors and earthing switches.
3) EDF specifications:
HN 64-S-41: A.C. metal-enclosed swichgear and controlgear for rated voltages above 1kV and up to and including 24 kV.
HN 64-S-43: Electrical independent-operating mechanism for switch 36 kV - 125 A.
Structure & Basic Components of 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 :
1) control motorisation;
2) surge arrestors.
Description
The complete unit includes the upper unit & the lower unit, the
upper unit by bus-bar cubicle, load switch, operating mechanism
cubicle and low-pressure cubicle, which can be assembled to be
a complete cabinet with the cable cubicle of lower unit, also
separated from the lower unit (see the picture). It is safe and (Operation& LV cubicle)
convenient to check & repair and reconstruct the equipment inside the upper unit and can be realized to
VCB & SF6 CB can be selected.
Ring Main Unit Structure
SM66 type switchgear unit is developed and produced by the company itself according to the requirement of domestic electrical system through absorbing the foreign technology, the main components of which are all the imported original binding.
The switchgear has double-fracture, switching on/off and earth switch, reversible contactor,
with SF6 as arc extinguishing medium. Reversible contactor lies in the die casting epikote crust that strengthens the structure.
Every switch is permanently sealed after charged by SF6 gas, the gas leakage can be detected by helium detector.
It is not limited for the vertical or horizontal installation, the typical installation inside the ring main unit is to place a separating steel plate between cable chamber for the horizontal installation, which
isolates the bus-bar from cable connector to conform with the most strict
safety requirement for running maintenance.
There are a weak point of structure behind the crust, in case inside happens the arcing when the load switch breaks and makes current, it would be pushed open, then the arc leakage valve on the top of
cabinet is pushed open to lead the over-pressure gas flow out of cabinet.
***Upper Unit
SFG LBS with switching on/off and earth switch
operating mechanism with mechanical position indicator
crust of busbar cubicle, integrated low-pressure chamber
interlocking device, bus bar, control cable tank.
***Lower Unit
Crust, current mutual-inductor, earth switch,
voltage mutual-inductor, cable bottom plate matched
with cable strutting pieces
Operating Mechanism
***Double-function and single-spring operation mechanism: K style
Function of switching ON/OFF:
Switch ON / OFF independently by operating by manually or motor
Earth switch function:
Switch on / off independently by operating lever, the operation energy is provided by compressed
spring, connector would be on or off after the spring released.
***Double-function and double-spring operation mechanism: A style
Function of switching on/off:
Switch on / off independently by operating lever and motor, the operation energy is provided by compressed spring, connector would be on or off after the spring released.
Switch on / off independently by button (O) or tripping unit or tripping device.
*** Earth switch function
Switch on / off independently by operating lever, the operation energy is provided by compressed spring, connector would be on or off after the spring released.
Transportation, Maintenance and Order
***Transportation and Storage
The switch cabinet can be transported by fork truck if guaranteed to be fixed on the bottom plate, and by handling or removing the entire entity if not fixed on bottom plate, but any case it should be
transported vertically, no allowance for inversion in order not to damage the internal components. The switch cabinet(even for that with outer package) should not be exposed outside for storage for a long time. The switch cabinet that needs the long-term storage should be put in the dry and ventilate
indoor warehouse. The period of validity of outer package of switch cabinet is normally no more than 1 year.
***Maintenance
Ring main unit is free of maintenance for 3 years under the normal conditions.
There is no need of maintenance and any lubrication for the single-spring and dual-spring operation mechanism of load switch.
The relay protection device should be checked by the requirement of the manufacturer before put into the running.
The maintenance periodicity for ring main unit is normally one time every year.
Maintenance by the below requirement:
Fasten all the electrical connectors(main bus bar, switch, cable, measuring meter)required by Installation and Operation Instruction.
Clean all the parts by dust collector(main switch, auxiliary switch, tripping mechanism, motor etc.) and check the appearance.
Have a switching on/off operation for all switches including earth switch.
Turn on auxiliary control electric source not giving the remote control signal to have a electrical order operation.
Clean the busbar cubicle and cable cubicle.
***Order
Complete-set Product:
The below documents are attached with the switch panel when out of factory;
Qualification Certificate of Product;
Installation and Operation Instruction;
Packing List;
Engineering Design Document of Product;
Accessory of switch panel :
one operating handle of load switch attached with each complete set;
The customer should offer the following information for order:
Wiring diagram of Main circuit Loop and Special Technical Requirement;
Installation Arrangement Plan of switch panel;
Specification of component inside switch panel and the schematic diagram of auxiliary loop and control loop diagram.
Other written documents specially required..
Ring Main Units series & Expanding Products.
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