SE Unveils Ultra-High Voltage Switch Capable of Uninterrupted Power Supply
Suitable for industrial sites that suffer significant damage during power outages, such as hospitals
Reliability guaranteed in compliance with UL891, C37.20.2 standards


Schneider Electric launched the Automatic Load Transfer Switch (ALTS) 'ASCO 7000' series on the 21st. ASCO is a subsidiary of Schneider Electric and a leading company in the Closed Transition Transfer Switch (CTTS) sector.

ALTS is an extra-high voltage switch that accepts 22.9kV voltage coming from a substation in duplicate at the user's site and quickly transfers to the standby substation power source in the event of a power outage or voltage drop in the main power source. Since a momentary power outage of approximately 400ms inevitably occurs when transferring from the main power source to the standby power source or vice versa, it was difficult for the operator to conduct a transfer test on the ALTS once installed unless there was a particular problem.

In these situations, maintenance management is not carried out regularly, resulting in frequent power outages or cases where ALTS does not operate properly when KEPCO notifies of a power outage. With the introduction of the Asco 7000 ALTS, operators can manually switch between the two power sources at any time by pressing the switch button, thereby increasing the stability of the overall power supply for the user.

◇ Increased durability and reliability compared to existing products

The Asco 7000 ALTS is based on the American safety standard UL certification (UL891) and the American National Standards Institute (ANSI) C37.20.2 standard, and has higher durability and reliability than the existing Asco ALTS that meets the IEC60265-1 standard. In particular, it is manufactured with a closed switchgear (Metal Clad Switchgear) structure according to the ANSI C37.20.2 standard, so that in the event of an arc accident, the switch can be sealed in a grounded metal box to prevent the accident from expanding.

In addition, the safety has been enhanced compared to the existing ALTS, which was vulnerable to arc accidents, with the Metal Enclosed Switchgear structure, in which all devices are installed together without dividing the compartments. The main bus and primary contacts are insulated, and fuse protection is provided on the primary and secondary sides of the instrument transformer. In addition, continuous current tests, withstand voltage, and short-circuit current tests have been conducted more stringently than the IEC standard.

Unlike existing products that applied fixed SF6 circuit breakers, the Asco 7000 ALTS applied a vacuum circuit breaker (VCB), and as a draw-out type, it allows for quick maintenance in case of product problems. Existing SF6 circuit breakers required the operator to periodically check the SF6 gas charge amount using a gas pressure gauge, and usually had to be refilled once every three years, which was inconvenient. In addition, SF6 circuit breakers have the disadvantage of having a serious impact on global warming.

ALTS must secure the stability of power to the user by quickly switching to a standby power source in the event of a sudden power outage or voltage drop. Since ALTS cannot operate due to battery discharge, significant damage occurs, so periodic battery replacement is essential. Asco 7000 ALTS does not require a separate operating power source, and when the main power source or standby power source is connected, ALTS supplies the operating power on its own, ensuring stability and reliability.