Eaton Energy Saver System (ESS)

The rising demand for high availability, reliability and efficient power is a continuous challenge for data centre operators. Improving energy efficiency can help address environmental, regulatory and economic pressures.

Eaton has developed technologies that improve system efficiency without compromising reliability under its Energy Advantage Architecture (EAA) umbrella. Energy Saver System (ESS) is one of these technologies. It is claimed to reduce energy consumption without compromising load protection by enabling large, three-phase uninterruptible power supply (UPS) systems to operate at 99% efficiency.

In ESS mode, the UPS safely provides mains current directly to load when the input is within the acceptable limits by its voltage and frequency. If input power goes outside the preset limits by frequency or voltage, the UPS switches to double conversion. If input power is outside the tolerances of the system, the UPS draws power from available battery modules.

Detection and control algorithms continuously monitor incoming power quality and allow the UPS to engage power converters in less than 2 ms when the utility source goes out of predefined limits by its voltage or frequency, thus always providing secured power to the critical load while maximising efficiency. In case of the UPS detecting a fault condition while operating in ESS, the UPS is capable of detecting and determining whether the fault is caused by load or if it is upstream from the UPS. A fault at the bypass source results in immediate switchover to the inverter; a fault in the load keeps the UPS in Energy Saver System.

The UPS with ESS features three configurable modes of operation: standard double conversion mode: the UPS operates as normal, supplying power through the power converters; ESS: the power converters are in ready state and the static bypass switch allows the UPS to supply mains power directly; and high alert mode: the UPS automatically transfers from ESS to double conversion and in case of multiple reoccurring utility line disturbances it stays there for a preconfigured time (default 1 h) until it is safe to return to ESS.

The UPS seamlessly executes transitions through different operating modes as needed. This is only possible with transformer-free topologies.

ESS is available to all 9390 and 9395 UPSs. Also, parallel UPS systems support operation in ESS mode. All earlier installations can be upgraded with ESS capability.