1.General
KYN28A-12 Steel-clad Removable-type Metal-enclosed Switchgear (hereinafter called switchgear for short) is applicable in the power system of three phases 50/60HZ. which is used to receive and distribute power as well as control. protect and moniter the circuit of power plant, substation and industrial and mining enterprises and high-rise buildings.
KYN28A-12 switchgear has the function of preventing various wrong operations including preventing loading mobile handcart, preventing grounding switch to circuit the breaker in closed position, preventing to close the charged grounding switch and preventing straying into charged compartment and other functions. Switchgear is equipped with excellent mid-set type of VS1, VD4 series high voltage vacuum circuit breaker and enclosed type vacuum circuit breaker. The secondary loop configuration of the switchgear is advanced and reliable control protection devices: Busbar with heat insulation materials or the insulation of the epoxy coating methods, optimizes the electrode shape and compacts the structure. The switchgear is safe and reliable power distribution equipment with advanced technology. stable performance, reasonable structure and easy usage. 

2.Working Conditions 
Ambient temperature : -15ºC- + 40ºC and the daily average temperature is below 35ºC
Humidity: daily average ≤95%
monthly average ≤90%
daily vapor pressure ≤2.2kpa
monthly vapor pressure ≤1. 8kpa
Altitude: ≤1000m
It is applicable in the place without obvious dust, smoke, corrosive or flammable gas, vapor, salt mist and so forth pollution.
The external vibration or ground shaking outside the switchgear and control equipment is negligible.
In the secondary system of induction electromagnetic interference amplitude is less than 1.6kv.

3.Special service conditions
Customer and manufacturer need to discuss when the environment conditions are not according to GB/T11022.

4.Structure and Operating Principle
KYN28A-12 switchgear is composed of two parts: cabinet and removable components (commonly known as handcart). Cabinet is separated into several functional compartments by steel plates, such as busbar compartment, Circuit breaker compartment, cable compartment and relay instruments compartment, etc.
The removable components of the switchgear are configured vacuum circuit breaker handcart, voltage transformer handcart, lightning arrester handcart, isolation handcart and fuse handcart, etc.

5.Specifications

6.Structure Features
Switchgear can be composed of double back-to-back arrangement. hence the security and flexibility of the switchgear improves, and the area reduces. 

Shell
The shell of the switchgear chooses imported aluminium zinc steel plate, processes through CNC machine and adopts multiple folding processes. The whole cabinet is featured with high precision and strong resistance to corrosion and oxidation. As a result of multiple folding process, the cabinet is lighter, stronger and neater than other similar cabinet. The cabinet uses packaged structure and connects each part with pull rivet nuts and high strength bolts. Short production cycle, versatile components and parts and less area are easy to organize production.

Handcart
The framework of the handcart is made of thin steel plate after CNC machine tool processing for assembling. Handcart and cabinet match up with high precision and safe, reliable and flexible mechanical interlocking. Handcarts are divided into different kinds by usage, such as circuit breaker handcart, voltage transformer handcart, metering handcart, isolation handcart, etc. and handcarts with same specification can be freely interchangeable. Handcart in the cabinet has disconnect test position and work location with positioning device respectively to ensure reliable interlocking. Each handcart adopts screw rod to push in and pull out, hence such convenient and flexible operation is suitable for the personnel on duty. When the handcart needs to be removed from the cabinet, the personnel just uses a special transport vehicle to pull it out. It is very convenient for all kinds of inspection and maintenance.

When the handcart is pushed into the circuit breaker compartment by the transport vehicle, the circuit breaker is in the disconnections position, and the indicator lights of the cabinet show its location. Only after the handcart completely locked. the screw structure can be derived and the handcart can be pushed into working position. When the handcart arrives at working position and the sudden increase of the pushing handle operating force stays motionless, its corresponding position indicator will show its location. The mechanical interlock of the handcart guarantees the circuit breaker to close only in working test position. And the handcart can be removed only when the circuit breaker is separate.

Compartment
The main electric components of the switchgear have their own independent compartment. such as circuit breaker handcart compartment, busbar compartment, able compartment and relay instruments compartment. The protection grade of each compartment is P2X. In addition to relay instruments compartment, the other three compartments all have pressure relief channel respectively. Due to the adoption of mid-set type, the space of the cable compartment greatly increases, so the device can receive multi-channel cables.