Savings through new technologies

Although it is at the heart of Eaton’s operations, technology is still merely a means to an end – its usefulness is measured by the benefits it brings for the customer. In today’s environment, businesses are constantly looking for ways to save energy and operating costs. Eaton aims to help them do this by developing power management solutions that utilise innovative new technology. Let’s take a look at some of these innovations.

Hot Sync provides absolute system reliability

The key feature of a UPS is its ability to supply uninterrupted, high quality power to critical loads at all times and in all circumstances. Eaton’s solution for absolute reliability is the patented Hot Sync® parallel load-sharing technology. It guarantees maximum system availability by eliminating the risk of a single point of failure that is inherent in traditional parallel UPS systems sharing the load with the master-slave principle.

Hot Sync is based on a parallel configuration in which two or more units share the same load. If one unit fails, the other units take over its tasks, isolate the damaged unit and continue to supply electricity without interruption. Hot Sync is unique because it enables the UPS units to operate completely independently; no communication wiring between units is required to transmit system-level information for output phase adjusting.

“To operate in parallel and achieve balanced load share, the outputs of the UPS modules must be in exactly the same phase angle. Any difference in the phase angle causes a difference in voltage between the modules. This is why phase synchronisation is crucial,” clarifies Elina Hermunen, Product Manager at Eaton Power Quality.

Hot Sync’s secret is the patented built-in digital signal processor (DSP) that continuously monitors UPS power module outputs and drives them towards synchronisation, fully independently of each other.

“Hot Sync completely eliminates the common single point of failure as the UPS’s modules operate in parallel without inter-module communication. This provides the highest reliability for the load,” Hermunen continues.

Hot Sync is available for both single- and three-phase products from 8 kVA up to 1100 kVA. In addition to parallel N+1 redundancy, the technology can be used to increase system capacity.

Power availability with various power supply configurations. Hot Sync-equipped systems are capable of paralleling for both redundancy and capacity.

Advanced Battery Management extends UPS battery life

The battery is the heart of the UPS; its service ability is critical for UPS operation and reliability. Though the battery may rarely be used, it must be fully operational when needed. Performance, however, decreases over time since batteries are electro-chemical devices. A worn battery may cause an unexpected loss of load.

With most UPSs, batteries are trickle-charged continuously. This reduces battery service life considerably – by as much as 50 percent – since batteries are constantly subject to drying and electrode corrosion. Eaton’s ABM® technology extends the overall battery life by optimising battery recharge time so that batteries are charged only when necessary. ABM first fully charges the batteries and then leaves them standby for the rest of the time. During this resting period, the battery condition and charge level are constantly monitored. Charge current is then applied at certain intervals.

What is more, the technology provides notice of the approaching end of useful battery service life as early as 60 days in advance. This gives the user plenty of time to organise a replacement battery. ABM also performs automatic and periodic self tests on the battery circuitry.

ABM technology is available for UPSs up to 1100 kVA.

Easy Capacity Test reduces testing costs – and saves time

In today’s environment, businesses are constantly looking for ways to save energy and operating costs.

Testing UPS performance at full power levels usually requires dummy loads on installation sites. With Easy Capacity Test, Eaton’s UPSs are able to test their entire power train under a full load stress without an external load being connected.

By using the UPS’s rectifiers and inverters as internal load banks, the Easy Capacity Test performs a full load test of all of the UPS’s power-handling components. Thus, there is no need to rent load banks or make temporary load connections, which saves both time and money. Because the UPS circulates power through itself and draws only minimal power from the mains source – 5 percent – the energy consumption of the UPS testing is significantly reduced.

The Easy Capacity Test is a standard feature of the Eaton 9395 and Eaton 9390.

Energy Saver System delivers 99% efficiency

Eaton’s Energy Saver System, or ESS, allows the UPS to safely provide mains current directly to a load when the input is within the acceptable voltage and frequency limits. If the limits are exceeded resulting in poor power quality, the UPS switches over to double conversion or battery backup with no interruption. The technology enables UPS efficiency to reach an impressive 99 percent.

“The efficiency improvement Energy Saver System brings is dramatic: at lighter loads the improvement is as high as 15 percentage units and at the upper load range as much as 5 percentage units. This brings significant energy cost savings,” Elina Hermunen says.

ESS allows the UPS to switch between three configurable operating modes. In the standard double conversion mode the UPS operates as normal, supplying power through the power converters. In the ESS mode the power converters are idle and the static bypass switch allows the UPS to supply mains power directly. If mains power is lost or exceeds preset output limits, the DC link that is kept active enables a seamless switchover to double conversion in less than two milliseconds. The third mode is a high-alert mode, in which the UPS switches from the ESS mode to double conversion for one hour. Power quality is constantly controlled during this time. If a high-alert command is received again, for example due to a thunderstorm, the one-hour timer will be reset.

While in ESS, the UPS is also able to detect whether an output fault has been caused by a source or by a load. A fault at the bypass source results in immediate switchover to the inverter; a fault in the load keeps the UPS in the ESS mode.

“ESS is perfect for environments in which the mains current is of good quality and the load is not overly sensitive to power fluctuations,” concludes Hermunen.

The Eaton 9395 and 9390 specific Energy Saver System is applicable to both single and parallel UPS configurations.

The UPS seamlessly transitions through different operating modes when needed.

Adaptive Capacity System optimises double conversion efficiency

UPS systems are rarely loaded at full capacity; lighter loads are the rule rather than the exception. At loads less than 40 percent of the full load rating, UPS efficiency decreases, thus increasing the system’s overall energy consumption. The solution is Eaton’s Adaptive Capacity System (ACS) technology, which allows the UPS to achieve higher efficiency for lighter loads.

With ACS, the UPS can decide which of the UPMs, or Uninterruptible Power Modules, are in idle mode. This way, the remaining power modules drive the load with higher efficiency. When the load increases again and more power modules are needed, the system shifts the load into additional modules immediately – in less than two milliseconds. ACS also allows the UPS system to be configured so that there is, for example, one module always prepared for redundancy. In this case, the additional modules are idle only when the load is less than N-1 in an N+1 configured parallel system.

“ACS is something completely new in the larger systems market,” says Otto Asunmaa, Head of Three-Phase UPS R&D at Eaton Power Quality, EMEA. “The improvement in the overall double conversion efficiency by several percentage units at lighter loads meets today’s energy efficiency requirements perfectly.”

Here is how ACS works: When a power module is in idle mode, the module will stop gating the inverter and rectifier but keep the DC link active. In case of a load step, the technology allows immediate return to active double conversion mode.

“ACS is especially useful in situations in which the load has not yet reached its maximum level, for example when the system is not fully set up. It is also useful when the load varies, for instance between weekdays and weekends,” Asunmaa says.

ACS adapts both to a single UPS consisting of multiple power modules and multiple UPS parallel systems. The Eaton 9395 specific feature will be launched in the third quarter of 2009.

ACS optimises the system efficiency by loading only those modules that are required to maintain sufficient power level. This considerably improves the overall system efficiency at lighter loads.

Otto Asunmaa (left) and Elina Hermunen (right) are at the front line of developing state-of-the-art technologies. “Eaton’s prime interest is to find solutions that help our customers to both save costs and act according to sustainable growth,” says Otto Asunmaa.