What is an ATS? Structure and principle of operation

BTB Electric

• News
• Jul 22, 2024
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ATS is a power converter with an important role in the operation process, shutting off the generator of the load system in case it is necessary to switch from the grid. In the following summary, BTB Electric will learn the structure of the ATS, the principle of operation and the practical application of this equipment.

What is ATS – Automatic Transfer Switches? 

ATS (Automatic Transfer Switches) with the task of automatically switching between power sources when the first power outage or a problem occurs such as overload or power short,… 

The ATS usually appears in the ATS power transfer cabinet , connected to all power sources, including at least grid power and backup generator power. This device acts as an intermediary between the power source and the load, operating similarly to a contactor. In addition, ATS can act as a backup power source, supplementing the main power source.

Structure of ATS

The standard ATS structure consists of two main parts: the switching unit and the controller. In addition, there are monitoring and protection units depending on the specific requirements of the load.

The switchgear includes:

• Force contacts play a role in transmitting electricity.
• Coil and mechanical interlock
• Mini switches and force contact operation monitors
• Circuit breakers that occur when the current is interrupted
• Electrical connectors and wires

The controller includes:

• The microprocessor controls the switching system, monitors the power on delay time and checks the power quality.
• Other components, depending on the system, are placed in a sealed box with the processor.
• The power switch section is separated from the above sections.

How ATS works

The first working principle of ATS is to prioritize 1 power source as the main source (usually the grid). Only when the main source is lost or has a problem, ATS will switch to the second source as the backup source. The designation of the main source and the backup source is done by the user. A system with ATS has 1 main source and 1 or more backup sources.

ATS working principle number 2 is independent power sources. Whether connected to 2 or more power sources, ATS ensures that only 1 source passes through this device and reaches the load at a time. The main source and the secondary sources run independently, can operate in parallel but ATS only receives 1 source. When the main source is operating and has a problem, the ATS will disconnect the main source and switch to the secondary source. When the main source is stable again, the ATS will reconnect to the main source.

The ATS operation process is almost instantaneous, ensuring that the time without power to the load is minimal to limit risks. In case the main and auxiliary sources operate in parallel to replace in time, this time is almost non-existent. You can read more about common ATS errors to recognize and have ways to prevent them.

Advantages and disadvantages of using ATS

Using an ATS power transfer switch helps the system to actively switch from the main source to the secondary source when the main source fails, reducing interruption time and reducing damage caused by electrical failures. The equipment in the system avoids damage during power outages and increases its lifespan. Then, when the main source is stable, the ATS automatically switches from the secondary source to the main source to save energy from the secondary source. Thus, the power source is flexibly converted without affecting the operation of the electrical equipment on the load side.

However, due to high investment costs, ATS is usually only used for large-scale electrical systems that require continuous operation of equipment such as production lines, cold storage, airports, ports, etc. On the other hand, when using an ATS, it is necessary to ensure that the generator is always available as a secondary source.

Select ATS power transfer switch from BTB Electric

BTB Electric automatic transfer switches has outstanding and instantaneous power transfer performance, specially applied to emergency power facilities with neutral position. This device is a single-coil type with energy-saving temporary excitation method. The device structure is sturdy, safe to operate.

ATS BTB Electric meets IEC/EN 60947-6-1 standard, has many versions with rated current from 63A to 2000A, selectable phase number 2P, 3P and 4P. Operators can choose to directly switch 2 power sources or turn off source A before switching to source B.