For El Corte Inglés, Spain's largest retailer with over 123 department stores throughout the country and €15 billion ($18.3 billion) in annual sales, quality merchandise and superb customer service are key to their continuing success. As part of their dedication to quality and service, El Corte Inglés has made it a point to install large standby generators in their stores to prevent utility outages from inconveniencing its customers or interrupting the flow of business. With an aggressive expansion plan to add four to six new stores a year, El Corte Inglés has turned to Cummins Power Generation for help in providing standby power systems that keep the lights on and the check-out lines moving.
The Xanadu mall in a southern suburb of Madrid boasts many stores, shops and restaurants, as well as an enormous indoor skiing complex, complete with falling snow, regardless of the weather outdoors. Anchoring this impressive, modern mall is an El Corte Inglés Hipercor, the Spanish version of a “hypermarket” that sells everything from groceries, to clothing, to sports equipment. Hipercor Xanadu has installed a 2.8MVA standby power system, consisting of two 1.12MW PowerCommand® C1400D5 generator sets and switchgear, from Cummins Power Generation, to provide standby emergency power in the event of a utility outage. The generators operate at 50Hz and feature PowerCommand digital master control systems for trouble-free operation and rapid paralleling.
Power for critical systems
“The Cummins generators are designed to supply emergency power for critical electrical loads systems at the Hipercor Xanadu,” says the chief of maintenance for the store complex. “The power is used to supply systems such as security cameras, ventilation, escalators, food refrigeration, computer systems and 60-80% of all the lighting in the store.”
The chief of maintenance says that the store's computers and data systems are also backed up by an uninterruptible power supply (UPS) system. “The UPS system protects our data (billing and orders) even during a micro-outage,” he says. “At no time can those systems be without power.”
The standby power system is contained in three separate rooms on the ground floor of the store: one holds the two generator sets and Cummins switchgear; another holds the fuel tanks for each engine; and the third houses the low voltage main switching network and transfer switches. Cooling for the generator sets is provided by remote radiators located on the roof of the building and incorporated into the building's chiller system. A portion of the building's chillers are kept operating when under generator-only power, in order to provide cooling for the generators.
Automatic operation
At the store's central service panel, the utility and generator mains come together for routing to the various loads. Under normal operating conditions, the utility mains supplies all of the store's loads. When a loss of utility power is detected, a start order is sent to the two standby generators, which start at the same time, synchronise and run in parallel. When the generators are ready to supply power – in about 10-12s – the utility mains are automatically isolated and the generators are connected to the critical loads.
Under typical utility failure conditions, power would be restored to critical systems within about 12s. Systems protected by the battery-backed UPS system would be supplied with power until the generators come on line. Fortunately for El Corte Inglés, the reliability of the electric power grid in this part of Spain is very good. In fact, the generators have not had to run for any significant outage since they were installed several years ago. Brief outages of only a few seconds' duration will, nonetheless, trigger the generators to start and synchronise. If utility power has been restored after a few seconds, the generators simply go into a cool-down cycle and then shut down.
Maintenance ensures reliability
To make sure the generators, switchgear and control system are always ready to produce emergency power, they are given a test run once every two weeks, with and without load. During testing situations, the PowerCommand digital master control allows the load to be gradually shifted from the utility to the standby generators, so there is no interruption of power to any loads. All of the maintenance and testing on the generators is done by Crima, a local service company whose services El Corte Inglés have experienced for a long time. Crima regularly checks and services the starting batteries, changes the engine oil and filters and performs other system checks on the entire system. The PowerCommand digital master controller assists in its own maintenance by providing data on more than 200 critical items.
Customers at El Corte Inglés's Hipercor Xanadu should never have to endure any power outage that will interrupt their shopping experience, thanks to the standby power system from Cummins Power Generation. It is part of El Corte Inglés' customer commitment to make shopping a quality experience. The commitment Cummins Power Generation has made to quality equipment and customer service has not gone unnoticed. “El Corte Inglés chose Cummins because of the reliability of their products, their fast service and the care they give us,” the chief of maintenance concludes.
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