Overview

KYN28A-12 indoor AC metal armored mid-mounted switchgear. It is suitable for three-phase AC rated voltage 12kV, rated frequency 50hz power system, used to accept and distribute electrical energy and the circuit control, protection and monitoring.

Conform to standard:

GB3906-2006 "3.6 ~ 40.5kv ac metal enclosed switchgear and control equipment"

GB11022-89 General Technical Conditions for High-voltage Switchgear

IEC298(1990) AC metal enclosed switchgear and control equipment with rated voltage above 1kV and below 50kV

DL404-97 Technical Conditions for Ordering Indoor AC High Voltage Switch Cabinet

Model Meaning

functions and characteristics

switchgear is designed for armored metal enclosed switchgear in GB3906-91. The whole is composed of two major parts, the cabinet body and the central extractable part (I. e. handcart) (see figure). The cabinet is divided into four separate compartments, the enclosure protection level is IP4X, and the level of each compartment and circuit breaker compartment door is IP2X when opened. It has overhead incoming and outgoing lines, cable incoming and outgoing lines and other functional schemes, which are arranged and combined to form a complete set of power distribution system devices. This switchgear can be installed, debugged and maintained from the front, so it can be back-to-back, composed of double arrangement and installed against the wall, which improves the safety, flexibility and reduces the floor space of the switchgear.

◆Shell and others

switchgear is made of aluminum-zinc thin steel plate, processed by CNC machine tools, and adopts multiple folding technology, so that the whole cabinet body not only has the advantages of high precision, strong corrosion resistance and oxidation resistance, but also has the advantages of light weight, high mechanical strength and beautiful appearance compared with other similar equipment. The cabinet body adopts an assembled structure, which is connected with a rivet nut and a high-strength bolt, so that the processing cycle is short, the parts are versatile, the area is small, and it is convenient to organize production.

◆Handcart

handcart frame is assembled from thin steel plates processed by CNC machine tools. Handcart and cabinet insulation coordination, mechanism interlocking safe, reliable and flexible. According to the purpose, the handcart can be divided into circuit breaker handcart, voltage transformer handcart, metering handcart, isolation handcart and so on. All kinds of handcarts are changed by module and building block, and handcarts of the same specification can be exchanged 100 percent freely. The handcart has a disconnection position, a test position and a working position in the cabinet. Each position is equipped with a positioning device to ensure reliable interlocking. It must be operated according to the interlocking anti-misoperation procedure. All handcarts are propelled and withdrawn by nuts and screw rods. The operation is light, flexible and suitable for the operation of the personnel on duty. When the handcart needs to be removed from the cabinet, a special transfer vehicle can be used to facilitate extraction, various inspections and maintenance; and the middle-mounted type is adopted, the entire handcart is small in size, and inspection and maintenance are extremely convenient.

◆ Compartment

switchgear have their own independent compartments, namely: circuit breaker trolley room, bus room, cable room, relay instrument room. The protection level of each compartment reaches IP2X; except for the relay compartment, the other three compartments have their pressure relief channels respectively. Due to the use of the central form, the cable room space is greatly increased, so the equipment can be connected to multiple cables.

a. Circuit Breaker Compartment

isolation for the handcart 15 to slide to the working position from the disconnected position and the test position in the cabinet. The partition 13 (flap) of the stationary contact box 6 is mounted behind the rear wall of the handcart compartment. When the handcart moves from the disconnected position and the test position to the working position, the valve on the upper and lower static contact boxes is linked with the handcart and automatically opened at the same time; when the handcart moves in the opposite direction, the valve will automatically close until the handcart retreats to a certain position and completely covers the static contact box to form effective isolation. Since the upper and lower valves can be operated separately, the valve on the live side can be locked during maintenance, so as to ensure that the maintenance personnel do not touch the charged body. When the door of the circuit breaker chamber is closed, the handcart can also be operated. Through the observation window of the middle door, the disposition, closing position and energy storage status of the handcart in the compartment can be observed.

B. Busbar Compartment

main busbar 4 is a single splicing through connection with each other. It is fixed by the support busbar 2 and the static contact box. The main busbar and connecting busbar are copper bars with rectangular cross section, which are combined by two busbars for high current load. The branch bus is connected to the static contact box 6 and the main bus by bolts, and no other support is required. For special needs, the busbar can be covered with heat shrinkable sleeve and connecting bolt insulation sleeve and end cap, and the busbar of adjacent cabinet is fixed with sleeve 3. In this way, the air buffer retained between the connecting busbars can prevent it from melting if there is an internal fault arc, and the sleeve 3 can effectively limit the accident in this cabinet and not spread to other cabinets.

c. Cable compartment

the switchgear is of the center-mounted type, the cable room space is large. The current transformer 7 and the earthing switch 8 are mounted on the rear wall of the compartment, and the lightning arrester 10 is mounted on the rear lower part of the compartment. After opening the door of the cabinet, the construction personnel can enter the cabinet from below for installation and maintenance. Cable connecting conductors in the cable room, each phase can be combined with 1~3 single-core cables. When necessary, each phase can be connected with 6 single-core cables in parallel, and the bottom of the cabinet connecting the cables is prepared with a slotted non-metallic sealing plate or a non-magnetic metal sealing plate to ensure convenient construction.

d. Relay instrument room

relay instrument room can be equipped with relay protection elements, meters, live monitoring indicators, and secondary equipment for special requirements. The control line is laid in the wire groove with sufficient space and has a metal cover plate to isolate the secondary line from the high pressure chamber. The left side trunking is reserved for controlling the introduction and lead-out of the small busbar, the control line inside the switch cabinet is laid on the right side, and there is a small busbar crossing hole convenient for construction on the top plate of the relay instrument room. During wiring, the top cover plate of the instrument room can be turned over to facilitate the installation of small busbars.

◆Prevent misoperation of interlocking device

switch cabinet has a reliable interlocking device, fully meet the "five" requirements.

a. The door of the instrument room is equipped with prompt buttons or KK-type changeover switches to prevent false closing and false disconnection of the circuit breaker.

B. when the circuit breaker handcart is in the test or working position, the circuit breaker can be closed and opened, and after the circuit breaker is closed, the handcart cannot move, thus preventing the circuit breaker from being pushed and pulled by mistake with load.

c. Only when the grounding switch is in the opening position, the circuit breaker handcart can be moved from the disconnection and test position to the working position. Only when the circuit breaker handcart is in the test and open position, the grounding switch can be closed (the grounding switch can be equipped with a voltage display device), thus preventing the grounding switch from being charged and closing the circuit breaker when the grounding switch is in the closed position.

d. When the grounding switch is in the opening position, the lower door and the rear door cannot be opened, thus preventing entering the charged interval by mistake.

e. When the circuit breaker handcart is in the test or working position and there is no control voltage, it can only be opened manually and cannot be closed.

f. When the circuit breaker is in the working position, the secondary plug is locked and cannot be pulled out.

g. Each cabinet can be equipped with electrical interlocking.

The switch device can also be equipped with an electromagnetic lock locking device on the grounding switch operating mechanism to improve reliability, and the order is selected according to the user's needs.

◆ Pressure relief device

Pressure relief devices are provided above the circuit breaker handcart room, busbar room and cable room. When an internal fault arc occurs in the circuit breaker or busbar, the internal air pressure of the switch cabinet rises with the appearance of the arc, and the special sealing ring installed on the door closes the front. The pressure relief metal plate equipped on the top will be automatically opened to release pressure and exhaust gas to ensure the safety of operators and switch cabinets.

Product Outline Dimension Drawing

Dimensions and Weight

Installation dimensions

switch cabinet

handcart

handcart skeleton is made of thin steel plates processed by CNC machine tools, riveted and welded. According to the purpose, handcarts can be divided into circuit breaker handcarts, voltage transformer handcarts, isolation handcarts, metering handcarts, etc. Handcarts of the same specification can be easily exchanged. The handcart has an isolation position, a test position and a working position in the cabinet, and each position is provided with a positioning device to ensure that the handcart cannot move casually when it is in the above position, and the interlock must be released when the handcart is moved.

B busbar room

busbar is led from one switchgear cabinet to another switchgear cabinet and fixed by the branch busbar and the static contact box. The flat branch bus is connected to the static contact box and the main bus by bolts, and does not need any other clamps or insulators. When the special needs of users and projects, the connecting bolts on the bus bar can be encapsulated with insulation and end caps. When the busbar crosses the switchgear partition, it shall be fixed with busbar bushing. If there is an internal fault arc, it can limit the spread of the accident to the adjacent cabinet and ensure the mechanical strength of the bus.

C Cable Room

Current transformers, grounding switches, lightning arresters and cables can be installed in the cable room, and a slotted removable aluminum plate can be prepared at the bottom to ensure convenient construction on site.

switch cabinet

D relay meter room

Relay instrument room is used to install various relays, instruments, signal indications, operating switches and other components. In addition, according to user requirements, a small busbar room can be added at the top of the instrument room, and sixteen small busbars can be laid.

pressure relief device

A pressure relief device is provided above the handcart room, busbar room and cable room. When an internal fault arc occurs in the circuit breaker, main busbar and cable room, the pressure release metal plate of the top device will be automatically opened to release pressure and discharge gas when the internal pressure of the switch cabinet rises and reaches a certain pressure with the occurrence of arc.

Latch Structure

the connection between the middle door and the cabinet adopts a locking structure, and is equipped with a lifting mechanism to make the middle door more convenient to open. When the middle door is in a closed state, the connection strength between the middle door and the cabinet is better, which enhances the effective resistance The ability of internal arcing failure.