Product Overview
The KYN28A-12 indoor AC metal-clad mid-mounted switchgear is suitable for power systems with three-phase AC rated voltage of 12 kV and rated frequency of 50 Hz, used for receiving and distributing electric energy and for controlling, protecting and monitoring the circuit.
Compliance with standards:
- GB3906-2006 "3.6-40.5 kV AC metal-enclosed switchgear and controlgear"
- GB11022-89 "General technical conditions for high-voltage switchgear"
- IEC298(1990) "AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to 50 kV"
- DL404-97 "Ordering technical conditions for indoor AC high-voltage switchgear"
Type Designation
Features & Advantages
The switchgear is designed as metal-clad metal-enclosed switchgear per GB3906-91. It consists of two main parts: the cabinet and the mid-mounted withdrawable part (i.e. the truck) (see figure). The cabinet is divided into four separate compartments; the enclosure protection class is IP4X, and IP2X between compartments and when the circuit-breaker room door is open. With overhead incoming/outgoing, cable incoming/outgoing and other schemes, a complete distribution system device is formed after arrangement and combination. The switchgear can be installed, commissioned and maintained from the front, so it can be installed back-to-back, in double rows or against the wall, improving the safety and flexibility of the switchgear and reducing the floor space.
Enclosure & others
The main frame of the switchgear is made of aluminum-zinc-coated thin steel sheet, machined by CNC machine tools with a multiple-folding process, so the whole cabinet not only has the advantages of high precision and strong anti-corrosion and anti-oxidation, but is also lighter in overall weight, higher in mechanical strength and more elegant in appearance than other similar equipment. The cabinet adopts an assembled structure joined by rivet nuts and high-strength bolts, resulting in a short processing cycle, strong universality of parts, small floor space and easy production organization.
Truck
The truck frame is made of thin steel sheet machined by CNC machine tools and then assembled. The truck is insulated in coordination with the cabinet, and the mechanism interlock is safe, reliable and flexible. By purpose, trucks can be divided into circuit-breaker trucks, voltage transformer trucks, metering trucks, isolating trucks, etc. All kinds of trucks vary in a modular, building-block manner, and trucks of the same specification can be **** freely interchanged.
The truck has the disconnected, test and working positions in the cabinet, each with a positioning device to ensure reliable interlocking; operations must follow the interlock anti-misoperation procedure. All trucks are pushed in and withdrawn by nut and lead-screw cranking, with light and flexible operation suitable for on-duty personnel. When the truck needs to be removed from the cabinet, a special transfer vehicle can easily draw it out for inspection and maintenance; and with the mid-mounted design, the whole truck is small in volume, making inspection and maintenance extremely convenient.
Compartments
The main electrical components of the switchgear each have an independent compartment: circuit-breaker truck compartment, busbar compartment, cable compartment and relay instrument compartment. The protection class between compartments all reaches IP2X; except the relay compartment, the other three compartments each have a pressure-release channel. With the mid-mounted design, the cable compartment space is greatly increased, so the equipment can connect multiple cables.
a. Circuit-breaker compartment
Rails are installed on both sides for the truck 15 to slide in the cabinet from the disconnected and test positions to the working position. The shutter 13 (flap) of the static contact box 6 is installed on the rear wall of the truck compartment. When the truck moves from the disconnected/test positions to the working position, the flaps on the upper and lower static contact boxes are linked with the truck and open automatically; when moving in the reverse direction, the flaps close automatically until the truck retreats to a position completely covering the static contact boxes, forming effective isolation. Since the upper and lower flaps can be operated separately, during maintenance the flap on the live side can be locked, ensuring that maintenance personnel do not touch live parts. With the circuit-breaker room door closed, the truck can still be operated; through the observation window of the middle door, the open/close position of the truck in the compartment and the energy-storage status can be observed.
b. Busbar compartment
The main busbar 4 is spliced panel by panel with mutual penetration and is fixed via branch busbars 2 and static contact boxes. The main busbar and tie busbar are copper bars of rectangular section, doubled for large current loads. The branch busbars are bolted to the static contact box 6 and the main busbar without other supports. For special needs, the busbars can be covered with heat-shrink sleeves, insulated connecting bolts and end caps, and the busbars of adjacent cabinets are fixed by bushings 3. The air buffer retained between the connecting busbars can prevent melting in case of internal fault arcs, and the bushings can effectively limit the accident to this cabinet and prevent it from spreading to other cabinets.
c. Cable compartment
With the mid-mounted design, the cable compartment is spacious. The current transformer 7 and earthing switch 8 are mounted on the rear wall of the compartment, and the surge arrester 10 at the rear lower part. After opening the lower door, constructors can enter the cabinet from below for installation and maintenance. The cable connecting conductors in the cable compartment can accommodate 1~3 single-core cables per phase, and 6 per phase if necessary; the cabinet bottom for cable connection is fitted with slotted removable non-metallic plates or non-magnetic metal plates, ensuring convenient construction.
d. Relay instrument compartment
The relay instrument compartment can install relay protection elements, meters, live-line monitoring indicators and special secondary equipment. Control wires are laid in trunking with sufficient space and metal cover plates, isolating the secondary wires from the HV room. The left trunking is reserved for the introduction and leading-out of control small busbars; the control wires inside the switchgear itself are laid on the right; small busbar through-holes for convenient construction are reserved on the roof plate of the relay instrument compartment. When wiring, the roof cover plate of the instrument compartment can be turned over to facilitate small busbar installation. The four independent compartments are isolated from one another, limiting the fault influence range of the KYN28A-12 indoor AC metal-clad mid-mounted switchgear to a single compartment.
Anti-misoperation Interlocking Devices
The switchgear has reliable interlocking devices, fully meeting the "five-prevention" requirements.
a. The instrument room door is fitted with a prompting button or KK-type changeover switch to prevent erroneous closing/opening of the circuit breaker
b. Only when the circuit-breaker truck is at the test or working position can the circuit breaker be closed/opened; moreover, after the circuit breaker is closed, the truck cannot be moved, preventing erroneous pushing/pulling of the breaker under load
c. Only when the earthing switch is open can the circuit-breaker truck be moved from the disconnected/test positions to the working position; only when the circuit-breaker truck is at the test/disconnected positions can the earthing switch be closed (the earthing switch can have a voltage display device), thus preventing erroneous closing of the earthing switch when live and preventing closing the circuit breaker with the earthing switch closed.
d. When the earthing switch is open, the lower door and rear door cannot be opened, preventing erroneous entry into live compartments.
e. When the circuit-breaker truck is indeed at the test or working position without control voltage, only manual opening is possible, not closing.
f. When the circuit-breaker truck is at the working position, the secondary plug is locked and cannot be removed.
g. Electrical interlocks can be installed on each cabinet.
An electromagnetic lock can also be added to the earthing switch operating mechanism to improve reliability, ordered per user needs.
Pressure-release Devices
Pressure-release devices are arranged above the circuit-breaker truck compartment, busbar compartment and cable compartment. When an internal fault arc occurs in the circuit breaker or busbar, the pressure inside the switchgear rises with the arc; a special sealing ring on the door seals the front, and the pressure-release metal plate on the top opens automatically to release pressure and vent gas, ensuring the safety of operators and the switchgear.
Position Interlock between Secondary Plug and Truck
The connection between the secondary wires of the switchgear and those of the circuit-breaker truck is realized through a manual secondary aviation plug. The moving contacts of the secondary plug are connected to the circuit-breaker truck via a nylon corrugated telescopic tube, and the secondary static contact seat is installed at the upper right of the truck compartment. Only when the circuit-breaker truck is at the test or disconnected position can the secondary plug be inserted or removed; at the working position, the secondary plug is locked by mechanical interlock and cannot be removed.
Live-line Display Device
The switchgear can be fitted with an optional live-line display device for monitoring the primary circuit. It consists of a HV sensor and a display unit. If required by the user, it can not only indicate the energization of the HV circuit but also work with electromagnetic locks to forcibly lock the earthing-switch handle and mesh door, preventing live closing of the earthing switch and erroneous entry into live compartments, thus improving the anti-misoperation performance of the product.
Condensation & Corrosion Prevention
To prevent the hazards of condensation in high-humidity climates or climates with large temperature variations, heaters are installed in the circuit-breaker room and the cable compartment respectively, so as to be used in such environments and prevent corrosion.
Earthing Device
A separate 5×40 mm earthing copper bar is provided in the cable compartment, running through adjacent switchgear with good contact to the cabinet. This earthing bar serves components requiring direct earthing. Meanwhile, since the whole cabinet is spliced with aluminum-zinc-coated sheets, the entire cabinet remains in a well-earthed state, ensuring the safety of operating personnel touching the cabinet. The earthing system of the KYN28A-12 indoor AC metal-clad mid-mounted switchgear runs continuously, providing reliable earthing protection for the equipment and operating personnel.
Main Technical Parameters of the Vacuum Circuit Breaker
| Item | Unit | Value |
|---|---|---|
| Rated voltage | kV | 3.6、7.2、12 |
| Rated frequency | Hz | 50 |
| Circuit-breaker rated current | A | 630、1250、1600、2000、2500、3150 |
| Switchgear rated current | A | 630、1250、1600、2000、2500、3150 |
| Rated short-time withstand current (4 s) | kA | 16,20,25,31.5,40,50 |
| Rated peak withstand current (peak) | kA | 40,50,63,80,100,125 |
| Rated short-circuit breaking current | kA | 16,20,25,31.5,40,50 |
| Rated short-circuit making current (peak) | kA | 40,50,63,80,100,125 |
| Rated insulation level 1-min power-frequency withstand voltage |
kV | 24、32、42 |
Rated insulation level lightning impulse withstand voltage |
kV | 40、60、75 |
| Protection class | Enclosure IP4X; IP2X between compartments and with the circuit-breaker room door open | |
Normal Service Conditions
- Ambient air temperature: maximum +40℃, minimum -15℃.
- Relative humidity: daily average ≤95%; daily average water vapor pressure not exceeding 2.2 kPa; monthly average ≤90%; monthly average water vapor pressure not exceeding 1.8 kPa.
- Altitude: below 1000 m.
- Seismic intensity: not exceeding degree 8.
- The surrounding air shall not be obviously polluted by corrosive or combustible gases, water vapor, etc.
- Places without violent vibration.
- For use beyond the normal conditions specified in GB3906, it shall be negotiated with our company.
The KYN28A-12 indoor AC metal-clad mid-mounted switchgear can operate stably for a long time under the above normal conditions; for special conditions, consult the manufacturer.
Installation Dimensions
| Cabinet width A | Cabinet depth B | L1 | L2 | L3 | L4 |
|---|---|---|---|---|---|
| 800 | 1500 cable | 530 | 630 | 150 | 490 |
| 800 | 1660 overhead | 530 | 630 | 310 | 650 |
| 800 | 1500 cable | 730 | 830 | 150 | 490 |
| 1000 | 1660 overhead | 730 | 830 | 310 | 650 |
Outline Dimensions
Height: 2300
Width:
- Rated current 1250 A and below: 800
- Rated current 1600 A and above: 1000
Depth:
- Cable incoming/outgoing: 1500
- Overhead incoming/outgoing: 1660
Switchgear Outline Dimensions Diagram
A Truck
The truck frame is made of thin steel sheet machined by CNC machine tools and then riveted and welded. By purpose, trucks can be divided into circuit-breaker trucks, voltage transformer trucks, isolating trucks, metering trucks, etc.; trucks of the same specification are easily interchangeable. The truck has the isolated, test and working positions in the cabinet, each with a positioning device to ensure that the truck cannot be moved arbitrarily at these positions, and the interlock must be released when moving the truck.
B Busbar compartment
The busbar runs from one switchgear cabinet to another, fixed by branch busbars and static contact boxes. The flat branch busbars are bolted to the static contact boxes and the main busbar, requiring no other clamps or insulators. For special user and project needs, the connecting bolts on the busbars can be sealed with insulation and end caps. When the busbar passes through the switchgear partition, it is fixed by busbar bushings. In case of internal fault arcs, the accident can be limited from spreading to adjacent cabinets, and the mechanical strength of the busbar is guaranteed.
C Cable compartment
The cable compartment can install current transformers, earthing switches, surge arresters and cables, with slotted removable aluminum plates at the bottom to ensure convenient site construction.
Switchgear Outline Dimensions Diagram
D Relay instrument compartment
The relay instrument compartment is for installing various relays, meters, signal indicators, operating switches and other components. In addition, a small busbar room can be added on the top of the instrument compartment per user requirements, in which sixteen ways of control small busbars can be laid.
Pressure-release Devices
Pressure-release devices are arranged above the truck compartment, busbar compartment and cable compartment. When an internal fault arc occurs in the circuit breaker, main busbar or cable compartment, the pressure inside the switchgear rises with the arc; after reaching a certain pressure, the pressure-release metal plate on the top device opens automatically to release pressure and vent gas, ensuring the safety of operators and the switchgear.
Latch structure
The connection between the middle door and the cabinet adopts a latch structure with a lifting mechanism, making the middle door easier to open; when closed, the connection strength with the cabinet is better, enhancing the ability to withstand internal arcing faults.
Related Products
High-voltage switchgear of the same series and other types available:
- KYN61-40.5(Z) Metal-clad Draw-out AC Metal-enclosed Switchgear
- XGN66-12(Z) Fixed Enclosed Switchgear
- XGN15-12 Box-type Fixed AC Metal-enclosed Switchgear
- HXGN-12 Box-type Fixed AC Metal-enclosed Switchgear
- HXGN17-12 Box-type Fixed AC Metal-enclosed Switchgear
- SRM-12 Fully Enclosed Fully Insulated Gas-insulated Ring Main Unit
