Product details

overview

KYN28A-12 indoor AC metal armored mid mounted switchgear. It is suitable for three-phase AC power systems with a rated voltage of 12kV and a rated frequency of 50Hz, used for receiving and distributing electrical energy, and for controlling, protecting, and monitoring circuits.

Compliant with standards:

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 Switchgear"

Model meaning

Model Meaning

Function and Features

The switchgear is designed according to the armored metal enclosed switchgear in GB3906-91. The overall structure consists of two main parts: a cabinet and a center mounted withdrawable component (i.e. handcart) (see figure). The cabinet is divided into four separate compartments, with a protection level of IP4X for the outer shell. When the doors between each compartment and the circuit breaker compartment are opened, the protection level is IP2X. Having overhead incoming and outgoing lines, cable incoming and outgoing lines, and other functional schemes, arranged and combined to form a complete distribution system device. This switchgear can be installed, debugged, and maintained from the front, so it can be back-to-back, arranged in double, and installed against the wall, improving the safety, flexibility, and reducing the footprint of the switchgear.

◆ Shell and others

The main cabinet frame of the switchgear is made of aluminum zinc coated steel plate, processed by CNC machine tool, and adopts multiple folding process, which not only has the advantages of high precision, strong corrosion and oxidation resistance, but also makes the cabinet lighter in weight, higher in mechanical strength, and more beautiful in appearance compared to other similar equipment cabinets due to the use of multiple folding process. The cabinet adopts an assembled structure, connected by rivet nuts and high-strength bolts, which shortens the processing cycle, enhances the universality of components, occupies less space, and facilitates production organization.

◆ Handcart

The handcart frame is assembled from thin steel plates processed by CNC machine tools. The handcart and cabinet are insulated and coordinated, and the interlocking mechanism is safe, reliable, and flexible. According to their usage, handcarts can be divided into circuit breaker handcarts, voltage transformer handcarts, metering handcarts, isolation handcarts, and so on. Various types of handcarts can be freely interchanged with each other in a modular and modular manner, with the same specifications of handcarts being 100% interchangeable.

The handcart has a disconnect position, a test position, and a working position inside 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 types of handcarts use nuts and screws to move forward and backward, and their operation is light and flexible, suitable for duty personnel to operate. When the handcart needs to move the cabinet, a dedicated transport vehicle can be used to easily extract it for various inspections and maintenance; Moreover, it adopts a mid mounted design, which makes the entire handcart small in size and easy to inspect and maintain.

◆ Compartment

The main electrical components of switchgear have their own independent compartments, namely: circuit breaker handcart room, busbar room, cable room, and relay instrument room. The protection level between each compartment reaches IP2X; Except for the relay room, the other three compartments have their own pressure relief channels. Due to the adoption of a mid mounted design, the space in the cable room is greatly increased, allowing the equipment to connect multiple cables. a. Circuit breaker compartment

Tracks have been installed on both sides of the isolation, allowing handcart 15 to move and slide from the disconnect position and test position to the working position inside the cabinet. The partition 13 (valve) of the static contact box 6 is installed behind the rear wall of the handcart compartment. When the handcart moves from the disconnected position, test position to the working position, the valves on the upper and lower static contact boxes are linked with the handcart and automatically open at the same time; When moving in the opposite direction, the valve automatically closes until the handcart returns to a certain position and covers the static contact box, forming effective isolation. Due to the separate operation of the upper and lower valves, the valve on the live side can be locked during maintenance to ensure that maintenance personnel do not touch the live body. When the circuit breaker room door is closed, the handcart can also be operated. Through the observation window of the middle door, the position of the handcart's opening and closing in the compartment can be observed, and the energy storage status can be displayed.

b. Busbar compartment

Main busbar 4 is a single unit spliced and interconnected. Fixed by supporting busbar 2 and static contact box. The main busbar and connecting busbar are copper bars with rectangular cross-sections, which are used to assemble double busbars for high current loads. The supporting busbar is connected to the static contact box 6 and the main busbar through bolts, without the need for any other support. For requirements, the busbar can be covered with heat shrink tubing and connecting bolt insulation sleeves and end caps, and adjacent cabinet busbars can be fixed with sleeve 3. The air buffer retained between the connecting busbars in this way can prevent melting in the event of an internal fault arc, and the sleeve 3 can effectively limit the accident within this cabinet without spreading to other cabinets.

c. Cable compartment

The switchgear adopts a mid mounted design, resulting in a larger space in the cable room. Current transformer 7 and grounding switch 8 are installed on the rear wall of the compartment, and lightning arrester 10 is installed on the lower part of the compartment. After opening the cabinet door, construction personnel can enter the cabinet from below for installation and maintenance. The cable connecting conductors in the cable room can accommodate 1-3 single core cables per phase. When necessary, 6 single core cables can be connected in parallel, and a detachable non-metallic sealing plate or non-magnetic metal sealing plate with open seams should be prepared at the bottom of the cabinet where the cables are connected, which facilitates construction.

d. Relay instrument room

The relay instrument room can be equipped with relay protection components, instruments, live monitoring indicators, and required secondary equipment. The control line is laid in a sufficiently spacious cable tray with a metal cover plate, which can isolate the secondary line from the high-voltage room. The left cable tray is reserved for controlling the introduction and extraction of small busbars, and the control wires inside the switchgear are laid on the right side. There are also small busbar crossing holes on the top plate of the relay instrument room for easy construction. When wiring, the top cover of the instrument room can be flipped over for easy installation of small busbars.

◆ Prevent misoperation of interlocking devices

The switchgear has reliable interlocking devices that meet the requirements of "five protections".

a. The instrument room door is equipped with informative buttons or KK type transfer switches to prevent accidental closing or opening of circuit breakers

b. When the circuit breaker handcart is in the testing or working position, the circuit breaker can only be opened and closed, and after the circuit breaker is closed, the handcart cannot move to prevent the circuit breaker from being pushed up with load.

C. The circuit breaker handcart can only be moved from the open and test position to the working position when the grounding switch is in the open position. The grounding switch can only be closed when the circuit breaker handcart is in the test and open position (the grounding switch can be equipped with a voltage display device), which prevents the live misoperation of the grounding switch and also prevents the grounding switch from closing the circuit breaker when it is in the closed position.

d. When the grounding switch is in the open position, both the lower and rear doors cannot be opened, preventing accidental entry into the live compartment.

e. The circuit breaker handcart is indeed in the testing or working position, and without control voltage, it can only be manually opened and cannot be closed. f. When the circuit breaker handcart is in the working position, the secondary plug is locked and cannot be removed.

g. Each cabinet can be equipped with electrical interlocks.

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

◆ Pressure relief device

Pressure relief devices are installed above the circuit breaker handcart room, busbar room, and cable room. When an internal fault arc occurs in the circuit breaker or busbar, accompanied by the appearance of the arc, the internal air pressure of the switchgear increases, and the sealing ring installed on the door seals the front. The pressure relief metal plate of the top equipment will be automatically opened, releasing pressure and venting gas to the operators and customers of the switchgear;

The position of the secondary plug and the hand army is interlocked according to the position

The connection between the secondary line of the switchgear and the secondary line of the circuit breaker handcart is achieved through manual secondary aviation plugs. The moving contact of the secondary plug is connected to the circuit breaker handcart through a nylon corrugated expansion tube, and the secondary static contact seat is installed in the upper right corner of the switchgear handcart room. The circuit breaker handcart can only be plugged in and unplugged from the secondary plug when in the test and disconnect position. When the circuit breaker handcart is in the working position, the secondary plug is locked due to mechanical interlocking and cannot be released.

◆ Live display device

If the user has a need, the switchgear can be equipped with an optional live display device to detect the operation of the primary circuit. The device consists of two units: a high-voltage sensor and a display. This device can not only indicate the power status of the high-voltage circuit, but also cooperate with the electromagnetic lock to achieve forced locking of the grounding switch handle and grid door, preventing the live closing of the grounding switch and the accidental entry into the live interval, thereby improving the anti misoperation performance of the supporting products.

◆ Prevent condensation and corrosion

In order to prevent the danger of condensation caused by high humidity or large temperature changes in the climate environment, heaters are installed in the circuit breaker room and cable room respectively for use in the above environment and to prevent corrosion.

Grounding device

A 5 × 40mm grounding copper busbar is separately installed in the cable room to connect adjacent switchgear and ensure good contact with the cabinet. This grounding strip is used for directly grounded components. At the same time, as the entire cabinet is assembled with aluminum zinc coated plates, it is in a good grounding state, making it safe for operators to touch the cabinet.

Main technical parameters of vacuum circuit breaker

Main technical parameters of vacuum circuit breaker

Normal usage conditions

Surrounding air temperature: temperature+40 ℃. Low temperature -15 ℃.

Relative humidity: Daily average relative humidity: ≤ 95%; The daily average water vapor pressure shall not exceed 2.2KPa; Monthly average relative humidity: ≤ 90%; The monthly average steam pressure shall not exceed 1.8KPa;

◇ Altitude: below 1000m. Seismic intensity: not exceeding 8 degrees.

The surrounding air should not be significantly polluted by corrosive or flammable gases, water vapor, etc.

◇ No places with severe vibrations.

When used beyond the normal conditions specified in GB3906, the user and our company shall negotiate.

Installation dimensions of structural schematic diagram

Outline dimension drawing of switchgear

Outline dimension drawing of switchgear

A handcart

The handcart frame system is made of thin steel plates processed by CNC machine tools and then riveted and welded. According to their usage, handcarts can be divided into circuit breaker handcarts, voltage transformer handcarts, isolation handcarts, metering handcarts, etc. Handcarts of the same specifications can be easily interchanged. The handcart has isolation, testing, and working positions inside the cabinet, and each position is equipped with a positioning device to ensure that the handcart cannot move freely when in the above positions, and the interlock must be released when moving the handcart.

B busbar room

The busbar is led from one switchgear to another and fixed through branch busbars and static contact boxes. The flat branch busbar is connected to the static contact box and the main busbar through bolts, without the need for any other clamps or insulators. When required by users and engineering, the connecting bolts on the busbar can be insulated and encapsulated with end caps. When the busbar passes through the switchgear partition, fix it with busbar conduit. If an internal fault arc occurs, it can limit the spread of the accident to adjacent cabinets and ensure the mechanical strength of the busbar.

C cable room

Current transformers, grounding switches, lightning arresters, and cables can be installed inside the cable room, and a detachable aluminum plate with a gap can be installed at the bottom for convenient on-site construction.

Outline dimension drawing of switchgear

Outline dimension drawing of switchgear

D Relay Meter Room

The relay instrument room is used to install various relays, instruments, signal indicators, operation switches and other components. In addition, a small busbar room can be added at the top of the instrument room according to user requirements, which can lay sixteen control small busbars.

pressure relief device

Pressure relief devices are installed above the handcart room, busbar room, and cable room. When an internal fault arc occurs in the circuit breaker, main busbar, or cable room, accompanied by the occurrence of the arc, the internal air pressure of the switchgear rises. After reaching a certain pressure, the pressure release metal plate of the top device will be automatically opened to release pressure and discharge gas, ensuring the safety of operators and switchgear.

Lock lock structure

The connection between the middle door and the cabinet adopts a locking structure and is equipped with a lifting mechanism, making it more convenient to open the middle door. When the middle door is in the closed state, its connection strength with the cabinet is better, enhancing the ability to effectively resist internal arcing faults.