28-24 Armored Removable AC Metal Enclosed Switchgear

electrical power panel

electrisity control box

Air-insulated switchgear
Scope of application:
Applicable to three-phase AC rated voltage 24KV, rated frequency 50HZ single bus, single bus disconnection and double bus power systems, used to receive and distribute electric energy and control, protect and monitor circuits.

factory general control box

Product Details

  1. Overview:
    28-24 armored removable AC metal-enclosed switchgear is suitable for three-phase AC rated voltage 24KV, rated frequency 50HZ single bus, single bus breaking and double bus power systems, used to receive and distribute electric energy and control, protect and monitor circuits. It is mainly suitable for power plants, small and medium-sized generator power transmission, industrial and mining enterprises and institutions power distribution and power system secondary substation power receiving, feeding and large high-voltage motor starting; the cabinet can be equipped with ZN63 (VS1) vacuum circuit breaker or ABB’s VD4 vacuum circuit breaker.
    This product complies with the requirements of GB3906 “3~35kV AC Metal-enclosed Switchgear”, GB/T11022 “Common Technical Requirements for High-voltage Switchgear and Control Equipment Standards”, IEC60298 “Rated Voltage 1KV Above 52KV and Below AC Metal Enclosed Switchgear and Control Equipment”, DL/T404 “Technical Conditions for Ordering Indoor AC High-voltage Switchgear”.
  2. Normal use conditions,
  3. Ambient temperature: maximum temperature +40℃, minimum temperature -15℃;
  4. Ambient humidity: daily average not more than 95%, monthly average not more than 90%;
  5. Altitude: below 1000 meters;
  6. Earthquake resistance: earthquake intensity not more than 8 degrees;
  7. Daily average water vapor pressure not more than 2.2Kpa, monthly average not more than 1.8kpa;
  8. The surrounding air should not contain obvious pollution such as corrosive or flammable gas, water vapor, etc.;
  9. No serious dirt and frequent severe vibration;

When used under normal environmental conditions exceeding those specified in GB3906, the user and the manufacturer shall negotiate.

  1. Model and meaning
  2. Structural features

4.1 The 28-24 cabinet is divided into four separate compartments, the shell protection level is IP4X, and the protection level of each small room and the circuit breaker room door is IP2X when it is opened. It has overhead inlet and outlet lines, cable inlet and outlet lines and other functional solutions, and can be arranged and combined into distribution devices in various forms. The shell of this switchgear is made of imported aluminum-zinc coated thin steel plate, processed by CNC machine tools, and adopts multiple folding processes, so that the entire cabinet body not only has high precision, strong corrosion resistance and anti-oxidation effect, but also adopts multiple folding processes, so that the cabinet body is lighter in overall weight, higher in mechanical strength and more beautiful in appearance than other similar equipment cabinets. The cabinet body adopts an assembled structure, connected by rivet nuts and high-strength bolts. This shortens the processing and production cycle, strengthens the versatility of parts, reduces the floor space, and facilitates the organization of production.

4.2 Cart

The frame of the cart is made of steel plate processed by CNC machine tools and riveted. The cart and the cabinet body are insulated and mechanically interlocked, safe, reliable and flexible. According to the purpose, the cart can be divided into circuit breaker cart, voltage transformer cart, metering cart, etc. The height and depth of various carts are unified, and carts of the same specifications can be interchanged. The trolley has an isolation test position and a working position in the cabinet. Each position is equipped with a positioning device to ensure reliable interlocking. It is necessary to operate according to the interlocking anti-misoperation procedure. All trolleys are pushed forward and withdrawn by shaking nuts and screws. The operation is light and flexible, suitable for on-duty personnel. When the trolley needs to be removed from the cabinet, it can be easily pulled out with a special transfer vehicle for various inspections and maintenance. Moreover, it adopts a central type, and the entire trolley is small in size, which is extremely convenient for inspection and maintenance.

4.3 Compartments in the switch cabinet

The main electrical components of the switchgear have their own independent compartments, namely: circuit breaker trolley room, busbar room, cable room, and relay instrument room. The protection level of each compartment reaches IP2X; except for the relay room, the other three compartments have their own pressure relief channels. Due to the central type, the cable room position is greatly increased, so the equipment can be connected to multiple cables.

(1) Circuit breaker compartment A guide rail for the circuit breaker trolley to slide is installed in the circuit breaker room. The trolley can move between the working position and the test isolation position. The movable curtain plate is made of metal plate and installed on the rear wall of the trolley room. When the trolley moves from the isolation/test position to the working position, the movable curtain plate in front of the static contact on the static contact box installed in the busbar compartment and the cable connection compartment (cable compartment) automatically opens. When the trolley is moved in the opposite direction, the movable curtain plate automatically closes and the static contact box is sealed, thereby ensuring that the operator does not touch the live body. The trolley is operated when the door of the switch cabinet is closed. The position of the trolley in the cabinet can be seen through the observation window. At the same time, the On (for closing the circuit breaker/OFF (for opening the circuit breaker) button and the ON/OFF mechanical position indicator and the energy storage/release status indicator on the trolley can also be seen.
(2) The frame of the withdrawable circuit breaker trolley is made of steel plates. The trolley is equipped with a vacuum circuit breaker and other auxiliary equipment. The primary moving contact with a spring contact system is installed on the output terminal of the circuit breaker by an arm. The control buttons of the circuit breaker operating mechanism and the opening and closing civilian indicators are all located on the trolley panel for easy operation. When the trolley enters the switch cabinet and reaches the isolation test position, the trolley shell is reliably connected to the switch cabinet grounding system, and the instrument protection and control circuits are also connected through The secondary plug is connected to the switch cabinet. When the trolley is moved to the working position, the primary circuit except the circuit breaker is connected.

(3) Busbar compartment

The busbar is led from one switch cabinet to another and fixed by the branch busbar and the static contact box. The main busbar and the connecting busbar are rectangular cross-section copper bars with rounded corners. Two rectangular busbars are required for large current loads. All busbars are covered with heat shrink tubing. The flat branch line is connected to the main busbar of the static contact box through bolt connection. The busbar is supported by an insulating sleeve where it passes through the switch cabinet partition. If there is an internal fault arc in the outgoing line of the cabinet, it can prevent the busbar from penetrating and melting, ensure that the accident does not spread to the adjacent cabinet, and avoid the main busbar from being deformed by the action of electric force.

(4) Cable compartment The rear wall of the cable compartment can be installed with current transformers, voltage transformers, and grounding switches. After the trolley and horizontal partition are removed, the construction personnel can enter the switch cabinet from the front to install the cable. There are specific cable connection conductors in the cable room, which can connect 1-6 single-core cables in parallel. At the same time, a removable metal cover plate is also provided at the bottom to ensure the convenience of on-site construction.

(5) Instrument compartment The instrument compartment can be equipped with relay protection elements, instruments, live monitoring indicators and secondary equipment with special requirements. The control line is laid in a wire trough with sufficient space and a metal cover. The left wire trough is reserved for the introduction and extraction of the control busbar. The secondary line inside the switch cabinet itself is laid on the right. There are also holes for the busbar to pass through on the side panels of the instrument compartment for construction.

4.4 Interlocking device to prevent misoperation

The switch cabinet has Reliable interlocking device provides reliable safety protection for operators and maintenance personnel. Its functions are as follows:

(1) After the trolley is moved from the working position to the isolation/test position, the movable curtain plate separates the static contact box to prevent accidental entry into the live compartment. During maintenance, the movable curtain plate can be locked with a padlock.

(2) When the circuit breaker is in the closed state, the trolley cannot be pulled out from the working position or pushed from the isolation/test position to the working position; the trolley of the circuit breaker has been fully locked in the test position or working position before it can be operated.

(3) The earthing switch can only be operated when the trolley is in the isolation/test position and outside the cabinet. When the earthing switch is in the closed state, the trolley cannot be withdrawn from the isolation/test position to the working position.

(4) When the trolley is in the working position, the secondary plug is locked and cannot be unplugged.
4.5 Pressure release device

Pressure release devices are installed above the trolley room, busbar room and cable room. When an internal fault arc occurs in the circuit breaker or busbar, the air pressure inside the switch cabinet will increase with the appearance of the arc, and the pressure release metal plate installed on the top will be automatically opened to release pressure and discharge gas to ensure the safety of the operator and the switch cabinet.

4.6 Position interlock between the secondary plug and the trolley

The connection between the secondary line on the switch cabinet and the secondary line of the trolley is realized through the secondary plug. The moving contact of the secondary plug is connected to the trolley through a nylon bellows, and the secondary static contact seat is installed on the upper right of the circuit breaker compartment of the switch cabinet. The secondary plug can only be plugged in and released when the trolley is in the test/isolation position. When the trolley is in the working position, the mechanical interlocking effect occurs, and the secondary plug is locked and cannot be released. The circuit breaker trolley can only be opened before the secondary plug is connected. Since the closing mechanism of the circuit breaker trolley is electromagnetically locked, it cannot be closed.
4.7 Live display device

distribution electrical panel

The switch cabinet is equipped with a live display device. The device consists of a high-voltage sensor and a portable display. The sensor is installed on the bus or feeder side, and the display interface is installed on the low-voltage compartment of the switch cabinet. When it is necessary to detect whether the three phases ABC are live, the plug of the portable display can be inserted into the L1L2L3 interface. If the display is activated, it means that the bus or feeder side is live, otherwise, it means that it is not live. At the same time, it can also be used as a phase sequence detector or electro-optical indicator, and its function is also to detect whether the high-voltage side is live.

4.8 Prevent condensation and corrosion

In order to prevent the danger of condensation in a climate environment with high humidity or large temperature changes. Heaters are installed in the circuit breaker and cable room respectively, so that it can be used in the above environment and prevent corrosion.

4.9 Grounding device

A 5×40mm grounding copper bar is separately installed in the cable room, which can penetrate the adjacent switch cabinets and have good contact with the cabinet body. This grounding bar is used for components that are directly grounded. At the same time, since the entire cabinet is connected with aluminum-zinc plates, the entire cabinet is in a good grounding state, ensuring the safety of the operating personnel and the cabinet.
automation electrical panel

VI. Ordering Instructions

  1. Main circuit scheme or main circuit system diagram;
  2. Control circuit electrical schematic diagram, terminal arrangement diagram;
  3. Switchgear layout plan;
  4. Cabinet color (if no requirements, according to company standards);
  5. List of components in the cabinet (including component name, specification model and quantity);
  6. List of required spare parts;
  7. If you have special requirements, please attach detailed instructions.