Effective Arc Fault Protection for Switchgear Every Data Center Has Two Important Priorities: to Uphold Safety and Ensure a Reliable Energy Supply

Customer Success Story: Market segment ISS IT & Business Services GmbH Commercial Buildings

Effective arc fault protection for switchgear Every data center has two important priorities: to uphold safety and ensure a reliable energy supply. It is therefore vital to protect the building’s low-voltage main distribution system against arc flashes, which can cause catastrophic damage. The Hewlett Packard (HP) data center in Rüsselsheim chose to update its switchgear with Eaton technology, including the ARCON arc fault protection system, to ensure the highest levels of safety and reliability.

Location: Background The resulting power failure Rüsselsheim, Germany “Eaton’s ARCON is likely to be costly and may The Hewlett Packard data last for days or even weeks. system makes an center in Rüsselsheim was Challenge: Additionally, the damage originally set up by Opel. Arc flashes pose a grave threat to to switchgear may be so important contribution To ensure full operational people, equipment and security extensive that it requires capacity, the low-voltage main of supply to the reliable complete replacement, distribution (NS-HV1), installed which can be expensive and Solution: in 1998, included an arc fault operation of the data time-consuming. The ARCON arc fault protection system. protection system center.” Rainer Weil, Challenge Arc flashes pose a threat Results: ISS IT & Business to a building’s power “As a service provider for Enhanced safety in the data center Services GmbH supply and should not be HP, we want to make sure due to active arc fault protection underestimated. They are we minimize any such risk,” caused by insulation flashes explains Rainer Weil, Site between the conductors, or Manager at the Düsseldorf- between the conductor and based ISS IT & Business earth, respectively. Even with Services GmbH (ISS). all the standard precautions, With more than 494,000 arc flashes can still occur in employees in 75 countries, electrical energy distribution ISS is a leading provider of systems today. facility services. There are many possible The ISS team is responsible causes, including human error for managing the entire while operating the switchgear, infrastructure at the data contamination, condensation or center, from cleaning to overvoltage. At their worst, arc electrical maintenance. flashes can replicate the force of an explosion, with potentially fatal consequences for anyone working on the installation or standing in its vicinity. The low-voltage main distribution contained The drive accelerates a copper bolt, which 20 sections of Eaton’s Modan switchgear, punctures an insulating plate and thereby which had proved its effectiveness over the creates an electrical contact. Regardless of preceding two decades. However, ISS and its strength, the current takes the line of HP decided to implement a new arc fault least resistance, redirecting away from the protection system. arc and towards the short circuit instead. Another key challenge was to ensure the From beginning to end, the complete continued operation of the data center process of detection, evaluation and at all times, despite the new installation quenching is completed in only requiring complete shutdown of the main two milliseconds. power distribution. Subsequently, the feed-in circuit breaker Eaton had to find a way to overcome this disconnects the affected busbar section The low-voltage main distribution at the and complete the project as quickly as from the system, with all non-affected Rüsselsheim data center is based on Eaton’s possible, despite the complexity of the sections remaining in operation. Modan switchgear, which was equipped with the existing plant, which includes six main ARCON arc fault protection system when it was The retrofit project involved the expansion busbar sections. first installed. of the old ARCON system, including the Solution optical fibers, as well as the installation of six new ARCON master modules (ARC- The implementation of the new ARCON EM) for the six busbar sections. Eaton’s arc fault protection system was carefully installation team connected these to two planned to minimize the impact of shutting 2.5 megawatt transformers, in addition down the primary, low-voltage, main to a diesel generator and a dynamic distribution (NS-HV1), which supplies Uninterruptible Power System (UPS), power to the building’s infrastructure which ensure emergency power supply. and climate control. The solution was to rely upon two newer low-voltage main After installing and wiring 12 converter distribution systems (NS-HV2 and NS-HV3), sets, as well as the current-sensor which provide the servers in the data modules (ARC-EC1), Eaton also installed new optical fiber technology and 13 center with power. These are also based Depending on the circumstances, the effects of sensor modules (ARC-EL3). Furthermore, on Eaton’s Modan range but, unlike the an arc flash can be comparable to those of Eaton configured and commissioned primary system , have the latest ARCON an explosion. system pre-installed. the system, including the completion of functional testing and updating of When the primary distribution system relevant documentation. (NS-HV1) was shut down, the two newer systems were able to carry the load. Results The timing of the installation was also The Eaton team completed the conversion carefully considered. “Since the building in only two-and-a-half weeks, without any consumes about 20 per cent less energy errors. The entire project, from tender to in the winter, compared with the summer, projecting, installation and acceptance, was when the servers require a high cooling managed by Eaton’s after-sales service. capacity, we implemented the project The new ARCON arc fault protection during the cold season”, says Mr. Weil. system, with its shorter reaction time and “Under these conditions, NS-HV2 and even more robust fiber-optic technology, NS-HV3 can take over from NS-HV1 for As part of the retrofit project, Eaton secured the has virtually eliminated the risk of arc-flash a limited time. We had scheduled three six main busbar sections with a new ARCON induced personal injury. At the same time, weeks for the conversion.” system, including a door-mounted master it also minimizes the potential damage to module and two slave modules in the control The ARCON system detects arc flashes the switchgear, thereby allowing it to return cabinet for current and light detection. based on two independent indicators: a to operation quickly and without incurring measuring transformer that detects any large costs. overcurrent and optical fiber sensors Eaton’s solution sets new standards of that register the light emitted by an security. As the project leader Rainer Weil arc flash. Should both detection values says: “Thanks to the professional work simultaneously exceed a fixed threshold, of Eaton’s after-sales service team, we the electronic evaluation systems will were able to put primary low-voltage main trigger the quenching device. distribution NS-HV1 back into operation The quenching device effectively cuts off even before the planned deadline. Our the energy supply to the arc. It initiates a arc fault protection concept places special three-phase short circuit that diverts the emphasis on ensuring that, in the event current away from the arc. This short circuit of an arc flash, the non-affected sections is activated as close as possible to the continue to be supplied with power. Less than one millisecond after the detection infeed, in parallel to the fault location, via a Today, the new ARCON system makes of an arc flash, the ARCON quenching device built-in pyrotechnic drive, which takes less an important contribution to the reliable initiates a three-phase short-circuit, thereby than one millisecond to perform operation of the data center.” cutting off the arc’s energy supply. this function.

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