Automatic transfer switch (ATS)

Automatic transfer switch (ATS)

Purpose and brief technical description
 Automatic transfer switch (ATS) is designed to restore power for the consumers through the automatic connection of emergency power when disconnected from the working power source and automatic restoration of basic supply, at restoration of the working power source.

ATS are widely used in electrical supply systems in industrial plants, communication facilities and transport to ensure the reliability of electricity for consumers of the 1 st and 2 nd category (see REI).

Options of power transfer:
1. The system of manual power transfer.
This system of power transfer is the most simple and common. Since switching from the main power line to the backup is made manually by the operator, thus this operation period is never permanent. The system of manual power transfer can include two or three switch-disconnectors or circuit breakers with manual control and mutual mechanical interlocking. Mutual interlocking does not allow simultaneous connection to two supply lines, even for a very short time.
   
2. The system of power transfer  with a remote control.
This system is the most widely used in installations with high rated current (over 400A). It does not require manual intervention. Switching from the primary power source to the backup is made by electrical control. The system of remote power transfer consists of two or three circuit-breakers or switch-disconnectors with mutual electrical interlocking of different configurations. Additionally mutual mechanical interlocking may be used, which protects against false actuations or improper actions of the operator.

3. The system of automatic power transfer.
Remote input provision can be supplemented by an automatic controller which carries out management of power supplies for a given algorithm. This solution provides optimal energy management:
• transition to backup power for the given external conditions;
• management of power sources;
• energy management;
• replacement of the emergency source of power, etc.

Automatic controller can be fitted with additional communication module that provides connection to the control device of a higher level.

Cabinet-performance of ATS devices (SATS)
Switchboards ATS  provide:
• constant monitoring of the availability of voltage in the circuits of the main and backup power sources;
• continuous comparison of current values of the voltage of the main and backup power supplies with predetermined maximum and minimum allowable voltage deviation from the nominal;
• continuous control of the phase sequence of primary and backup sources of power;
• automatic restoration of power electricity for consumers by adding a backup power supply, in cases of disappearance of the main power supply voltage, its reaching the prescribed limits or change the phase sequence;
• restoration of pre-damage power supply circuit of electricity for consumers with the given time delay after the restoration of the main power source according to the operator's command;
• rejection to use the primary or backup power supply;
• visual inspection of the availability of primary and backup inputs voltage, including contactors, switching the load to the primary or backup power sources, as well as violations of phasing network voltages.
The choice of the necessary functions listed above (except the basic) for a specific switchboard ATS is made by the Customer / designer on the basis of the provided single-line scheme and / or a brief technical description of the principle of work and conditions of the system switching.

The design and composition of the switchboard ATS
Structurally, the switchboard ATS can be manufactured in two versions: in mounted version or floor-base version, depending on the nominal commutation current and customer requirements. The design of the switchboard ATS provides easy access to controls and services, as well as the convenience of mounting and dismounting. Input of supply lines and outgoing lines is allowed above and below. The degrees of cabinet protection are IP30, IP31, IP43, IP54.
  
On the front of the switchboard ATS there may be located:
• control devices for electric energy parameters of the main and backup inputs;
• voltage indicators of the main and backup inputs;
• switching indicators of contactors of primary and backup inputs;
• indicators of violations in the phase order sequence of primary and backup inputs.
   
It should be noted that upon agreement with our organization, we can make additional functions for the manufactured switchboard ATS.
   
Assembling of the switchboards is performed only on the certified equipment based on components of Schneider Electric, which ensures high quality of switchboards. Manufactured by our company switchboards ATS can be either freestanding or integrated into the boards LCD-0, 4kV and IDD.