UPS S-ECO mode: a revolution in energy saving for data centers – Adaderana Biz

Data centers are fundamental to the digital economy. As energy prices continue to rise and industries strive to pursue green goals, there is a growing demand for green data centers.

How to optimize data center power consumption and reduce power utilization efficiency (PUE)? Uninterruptible power supply (UPS) products in more efficient modes of operation have a key role to play. The innovative S-ECO mode offers advantages over the standard ECO mode, balancing the need for ultra-high power efficiency and system stability.

Challenges in Traditional UPS Modes

The UPS is an essential component of data center backup power. It is used to provide stable power quality to critical applications and provide backup power to the load in the event of a power failure. However, while providing a reliable power source, the UPS consumes nearly 10% of a data center’s total energy. There is an urgent need to improve inverter efficiency through technology upgrades.

A traditional online double-conversion mode UPS converts utility power through the rectifier and inverter, which then supply high-quality power to the loads. This mode has high reliability but low efficiency and high power consumption.

ECO mode can be used when online double conversion mode cannot meet the higher efficiency requirements of the UPS. Operating in ECO mode, the UPS supplies the loads via static bypass, which is equivalent to direct mains supply. However, the standard ECO mode is not able to provide 0 ms switching and presents the problem of harmonic compensation, which compromises the stability of the system.

To solve the problems of traditional ECO mode and provide optimal power system performance, Huawei has developed advanced S-ECO mode.

What is S-ECO mode?

S-ECO mode is a TÜV-certified mode for Huawei’s UPS system that provides zero transfer time between different operating modes while delivering up to 99.1% efficiency. It optimizes the architecture and logic of the power supply. The mode is activated to solve problems of low system efficiency in online double conversion mode, and output interruption, large harmonics and input surge interference in ECO mode. S-ECO mode offers the following advantages: zero transfer time between different operating modes, high efficiency in the full load range, high voltage surge suppression and active harmonic compensation.

First, 0 ms interruption between different operating modes. When the inverter is operating in S-ECO mode, it automatically detects the power fluctuations of the bypass input. When the bypass input is normal, the bypass supplies power. When the bypass input is abnormal, the inverter will switch to inverter mode transparently. It complies with the class 1 dynamic response level defined in IEC 62040-3. The UPS will automatically return to bypass mode once bypass is recovered.

Second, S-ECO mode provides high efficiency in the full-load range. When the bypass is supplying power, the power consumption of the inverter is extremely low, and the system efficiency is over 99.1% at its maximum or over 98.5% when the load rate is higher than 20%.

Third, S-ECO mode suppresses power surges. When the bypass directly feeds the power supply, the surge from the bypass input is easily transmitted to the load ports. To deal with the high voltage surge, S-ECO mode uses high and low voltage blocking technology to compensate for voltage when it drops and absorb voltage when it increases. The output voltage has been verified to meet the requirements of the IEC 61000-4-5 overvoltage standard.

Fourth, the S-ECO mode implements active harmonic compensation. IT equipment power supplies perform the power factor correction (PFC) function. When the input power factor (PF) is good (> 0.9), the bypass can supply power directly. However, mechanical and cooling equipment, such as air conditioners, fans and water pumps, do not have the PFC function. When the bypass supplies power directly in traditional ECO mode, reactive power and high order harmonics are generated and flow through the power grid, which increases line loss, accelerates insulation aging and shortens service life equipment.


S-ECO mode can ensure stable and reliable power supply to various loads in data centers and critical power supply in different industries. According to the recently released UPS S-ECO Technology White Paper, UPS S-ECO mode can improve UPS system efficiency by 3-4% and reduce PUE by 0.03-0.04, which is equivalent to 1.5 to 2 million kWh. of electricity saved each year. If all data centers of 10 MVA or more use this technology, billions of kWh of electricity will be saved each year.

The highly efficient UPS mode of operation will facilitate green transformation and trigger an energy saving revolution for data centers. To learn more about S-ECO mode, please visit

Ramon J. Espinoza