What is ATS cabinet? Structure, function, operating principle

BTB Electric

• News
• Aug 5, 2024
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The ATS cabinet system is very important in every factory, construction or large building, with the role of ensuring continuous power supply when there is a power outage. The ATS cabinet system is increasingly integrated with modern equipment and technology, capable of automatic operation, and is a good solution to avoid economic losses when there is a power outage. Let’s learn about this electrical cabinet system with BTB Electric in the article below.

What is ATS cabinet?

ATS cabinet is an automatic transfer cabinet with ATS (Automatic Transfer Switches) as the main device. ATS cabinet has the function of automatically switching power source when the main power source has a problem causing the input power to fluctuate, drop voltage or be lost. This electrical cabinet system ensures a stable input power source for daily living, production and business activities.

ATS power transfer cabinet has 2 operating modes: manual and automatic. On the front of the ATS cabinet, there are buttons, indicator lights, and LCD display for the operator to monitor and adjust the cabinet’s operation. When the main power source loses phase or is overvoltage or has a power outage, the ATS cabinet will automatically switch to receive the secondary power source as programmed and disconnect the main power source. When the main power source is restored, the ATS cabinet will select the main power source again. Therefore, the ATS cabinet is an important control cabinet line in fields that need to ensure continuous power supply. In practice, the time to switch from the main power source to the secondary power source is about 5 – 10 seconds and the time to diagnose and switch back is about 10 – 30 seconds.

Function of ATS cabinet

The main function of the ATS cabinet is to quickly switch power sources for loads:

• Switch from main power to secondary power in case of main power failure.
• Switch from secondary power to main power when main power is stable again.
• Protect the load when the power source has errors such as power failure, voltage drop, phase loss, overvoltage, etc.

Additionally, the ATS can be programmed to switch the supply between two backup sources in the event of a failure of the first backup source.

Operating principle of ATS cabinet

When installed, the ATS power transfer cabinet is always installed with an industrial generator to always be ready for situations requiring power source conversion. The basic operating principle of the ATS cabinet is to monitor the operation of the main power source and quickly switch to backup power when the main source encounters errors: phase loss, overvoltage, voltage drop, frequency outside the allowable level, power failure, etc.

The steps for the ATS electrical cabinet to transfer power are as follows:

• Step 1: Start the generator engine (secondary power source) or solar battery.
• Step 2: Stop supplying main power to the load.
• Step 3: Connect the secondary power source to the load.

When the main power source is stable, the power transfer process on this electrical cabinet line will automatically reverse:

• Step 1: Disconnect the power supply from the secondary source to the load.
• Step 2: Turn on the main power source (main source) to the load.
• Step 3: Generate a stop signal for the secondary power source and let it idle for a while, then turn off the secondary power source.

For loads that require no power outages or power outages for too long, the ATS electrical cabinet system will ensure that the load is always connected to at least the main source and 1 secondary source. In addition, some high-end ATS cabinets are combined with synchronization cabinets for multiple generators (secondary sources), ensuring that the load is always supplied with sufficient power in all cases. 

ATS cabinet structure

The ATS cabinet system is designed as a cubic cabinet, the outer shell is made of galvanized steel with electrostatic paint. The cabinet size depends on the operating capacity and usage needs. Inside the ATS automatic transfer cabinet usually includes the following equipment:

ATS – Automatic transfer switch: The device has the function of converting power sources, playing the most important role in the ATS cabinet.
Distribution copper busbar system: Depending on installation diagram and cabinet capacity.
ATS controller: ATS active control.
MCCB and MCB: Switching and protecting electrical circuits
Accessories: push button, indicator light, LCD screen

The capacity, size or installation location of the equipment in the ATS electrical cabinet depends on the available installation diagram.

ATS power transfer cabinet specifications

• Quality standards: IEC 61439-1&2, IEC/EN 60439-1
• Finish standard: RAL-7035
• Cabinet material: 1.5/2mm electro-galvanized steel sheet
• Microprocessor Automatic control and protection
• Communication: USB/RS485/Ethernet optional
• Operating mode: Auto/Manual
• Rated operating voltage: up to 690V
• Protection level: IP5x – IP65
• Maximum temperature rise: 50ºC

Current types of ATS electrical cabinets

ATS power transfer cabinets are classified according to operating parameters and number of connected power sources:

• ATS 2-source cabinet: Connects to the grid power source and generator power source, is the most popular type today, used in buildings, factories, constructions,…
• ATS cabinet with 2 independent power sources from the grid and 1 secondary power source, used in large industrial zones. The cabinet prioritizes the use of 2 alternating power sources due to the characteristics of the continuous production line. The secondary power source is only for office, control, auxiliary, etc.
• ATS cabinet 1 main power source, 2 secondary power sources.
• ATS cabinet 1 solar power source (or wind power), 1 secondary power source.
• ATS cabinet 1 grid power source, 1 UPS backup power source

In addition, ATS electrical cabinets are classified according to current levels such as 100A, 250A, 400A, 630A, 800A, 1000A, … For small capacity cabinets, priority is given to choosing switching devices such as contactors and CBs. Large capacity cabinets choose MCCBs to allow large currents to pass through, increasing the durability of the cabinet.

Application of ATS power transfer cabinet

4 important functions of ATS power transfer cabinet applied in life:

• Ensure continuous power supply to loads, flexibly switch power supply between main source (grid) and secondary source (generator).
• Protect equipment and electrical systems from power outages
• Save energy for generator (secondary source) when grid power returns
• Minimize power interruption time, maximum interruption time is 30 seconds.

ATS is the most important component of the ATS automatic transfer switch with the role of controlling the power supply to the load, stabilizing the power source, and promptly fixing problems at the power source. 

ATS power transfer cabinets are now widely used from the electrical systems of apartment buildings, shopping centers, offices, etc. to the electrical systems of factories, workshops, etc. or the electrical systems of schools, hospitals, stations, wharves, airports, etc. In addition, in areas at the end of the power grid, where there are frequent natural disasters or technical requirements that require power conversion, ATS will also need to be installed.

Criteria for selecting ATS cabinets

When you need to install an automatic power transfer cabinet for an operating electrical system, consider the factors of current, voltage, capacity and quality of equipment in the cabinet:

• The rated current of the ATS cabinet is higher than the total current of the load system and meets the ability to expand the load in the future. The cabinet current level ranges from 100A to several thousand amps.
• The voltage level of the ATS electrical cabinet must be compatible with the voltage of the existing system. The voltage level in the civil electrical system is around 220V, industrial electrical is around 380V. In fact, the voltage level of the cabinet can reach over 1000VAC.
• Once you determine the current and voltage, you will determine the appropriate power level for the ATS system .
• The quality of the equipment in the ATS cabinet must be consistent, meet the needs of use, have appropriate technical parameters, and not cause conflicts when installed. Note that you should not choose a cabinet with a capacity that is too different from the capacity of the transformer station.

In addition, you need to pay more attention when choosing and installing ATS cabinets:

• The operating environment of the ATS system is a cool, dry place, not near flammable and explosive substances, not exposed to direct sunlight, not exposed to risks of extreme weather, etc.
• ATS electrical cabinets can connect to automatic electrical control systems to limit operating problems such as display errors, current transfer errors or fire and explosion risks, etc.
• Choose the parameters and size of the ATS cabinet suitable for the operating unit, avoid using too many devices in the cabinet causing waste.
• Consider the number of sources connected to the cabinet to suit the current situation and operating needs. For example, an ATS system installed in a building only needs 1 grid power source and 1 backup power source.

BTB Electric supplies electrical equipment for ATS power transfer cabinets

BTB Electric is a brand that provides quality equipment for ATS electrical cabinets in factories and offices in many large industrial zones. The equipment we provide includes ATS automatic power transfer switch, contactor, CB and some other equipment all under the BTB Electric brand. 

Industrial electrical equipment from BTB Electric meets EN, IEC quality standards, is tested by leading quality organizations such as Dekra, Intertek, … and carries the KEMA-KEUR brand. Refer to quality parameters and product catalogs at: https://btb-electric.com/vi/products/.