星空传媒

For a power protection system to be wholly effective, it must have a degree of flexibility that allows the user to upgrade the ups as required. Evaluating the size of the load and choosing a ups can be complex and requires expert guidance. Where a ups has to support a range of facilities an holistic approach is needed.

A recent upgrade by Allianz Cornhill Insurance of its main computer room at its headquarters in Guildford provides a classic approach to planning, selecting and installing an effective power protection infrastructure.

Like many companies in their sector, demand for their services is on a 24/7 footing. To meet this requirement, the firm has invested heavily in its IT infrastructure. This prompted it into re-evaluating its secondary power capacity in line with its risk management and disaster recovery strategies.

Working in conjunction with project design and management contractor Powerplan and Chloride Power Protection, two projects were identified: the replacement of the existing ups; and the replacement of the entire electrical infrastructure in the main computer room. The key objective of both projects was to eliminate single points of failure for all critical components within the power distribution network throughout the five-building complex.

The approach adopted was to bring together all the relevant parties: IT, property management, consultant, m&e and the ups supplier. "We had a situation where property services, who are responsible for the electrical side of the site, and IT, who are responsible for the services that emerge from the main computer room, were able to combine their expertise and resources," says Nick Hinchliff of Allianz Cornhill. The benefit was that every facet of the project remained under the joint control of Powerplan and Chloride Power Protection, and could be presented as a seamless service.

The main computer room is where the IT and power engineering philosophies meet, and these are very different. To solve this, Powerplan, Chloride Power Protection and the client established a project team that was empowered to resolve all issues relating to IT and the power infrastructure. As a result, a common understanding of the differing philosophies was attained and a power protection and distribution infrastructure addressing all needs could be delivered.

The replacement of the existing ups was driven by the need to increase the capacity and level of redundancy, and by the recognition that the ups was coming to the end of its effective life. Having addressed this issue, it was clear that the main computer room needed dual independent power feeds to avoid any single point of failure.

Replacing the power distribution system within the main computer room involved changing the N+1 power distribution unit (pdu) configuration and installing a dual feed supply. This was done via the replacement ups to two new pdus, each supported by two 600 A Chloride Cross static switches. In addition, 55 of the server cabinets were equipped with smaller Cross rack-mounted static switches to give the capability for a no-break transfer between the two supplies. The main drivers for this were to enable maintenance without impacting upon the availability of the IT services and to allow the client to increase the period of time that the IT services are available.

One particular concern was the location of the existing ups room in the basement. "The physical infrastructure can have an influence on the performance and operation of a ups," explains Alan Fry, technical support director at Chloride Power Protection. "With the Allianz Cornhill complex being built on a flood plain, the potential for the ingress of water into the basement was a remote possibility and a potential threat to the ups, even though precautions had been taken to prevent this." It was therefore recommended to install two Chloride EDP90 400 kVA ups in an N+N configuration, with each fed from a separate switchroom.

"The first unit was installed on a plinth in the existing basement room and the other, along with the batteries and switchboard in a purpose-designed portable plantroom, located on a flat roof adjacent to the second floor computer room," reports Peter Marsh, md of Powerplan. "Taking this approach ensured that the load is constantly shared between both ups and will be fully supported should one fail or need to be taken out of service."

Given the deficiency in the existing ups infrastructure, the first ups was installed and connected to the load in a temporary capacity at the start of the project. With this in place, the project team could work on the remainder of the scheme. The replacement of the power distribution system was running concurrently with that of the ups upgrade. Here, the mains supply, data, communications and other services were located in the floor void. Over time, modifications had been made to these, so to simplify the power distribution it was decided to take them overhead, separate from the IT cabling.

The solution involved installing two sets of six 250 A busbars (one set for each pdu) fitted with tapping boxes. This configuration provides dual redundancy, so should either pdu fail the connected cabinets will still be powered. Using data from a detailed analysis of all the equipment within the room to measure the load, engineers determined the required sizes for the tapping boxes on the busbars, with these varying between 16 and 32 A. The system can accommodate tapping boxes every 500 mm, with a total capacity of 264.

A 945 Trend bms is employed so that the client can monitor all the power coming into the complex and some of its usage. The communications facilities offered by the new ups, together with the LIFE 2000 monitoring package and power monitoring devices incorporated in the pdu, have extended this capability and enable integration of the power protection facility with the bms.

The key to the project's success was the co-ordination of the works that allowed Allianz Cornhill to maintain full IT services throughout. "From the IT point of view, when we were migrating from the old to the new electrical supply only a minimal out of hours shutdown was required," says Allianz Cornhill's Nick Hinchliff. "Using the overhead busbar system enabled us to install new cabling without disrupting the underfloor distribution systems and therefore minimised the risk to our business. The overhead busbar gave us very great flexibility for reorganising equipment."

The replacement of the ups infrastructure and the upgrading of the power supply within Allianz Cornhill Insurance's main computer room has been a major undertaking, made even more complex by the client needing to continue its operations throughout the project period.

By adopting a strategy based on the tenets of design, delivery and support, Powerplan and Chloride Power Protection have been successful in providing the client with a solution to its current and foreseeable future requirements, and one that has eliminated any single points of failure.