With over 1.4 million square feet of retail space and 270 stores under one roof, Meadowhall in Sheffield is one of the UK’s largest and most successful shopping centres. Recently, the decision was taken to further enhance the Meadowhall shopping experience by adding comfort cooling systems and a new energy efficient lighting system. Distribution equipment from Square D, a brand of Schneider Electric, was chosen to provide the electrical supply for these new installations.
After carefully surveying the market for low voltage electrical switchgear and carrying out a rigorous competitive tendering exercise, Crown House Engineering, the main contractors for the Meadowhall development programme, chose to use products from Square D for all major functions.
This meant that Crown House Engineering would need only to work with a single supplier, which was seen as a major benefit as it would simplify contractual and pricing issues as well as ensuring compatibility of equipment throughout the project and, if any technical problems should arise, guaranteeing that there could be no question of divided responsibilities.
The electrical systems required for the project are extensive, and include two new substations fed by the local network operating company at 11kV. For each of these substations, Schneider Electric supplied a cast resin transformer rated at 1.25MVA, accompanied by a Square D Powerstyle 3 LV switchboard. The boards use MCCBs for the incomer and for all outgoing circuits.
A major benefit of the Powerstyle 3 boards is their use of Plug-on MCCB technology, which means that additional circuits can be added easily and quickly. This is an important advantage in retail environments like Meadowhall, where flexibility is essential, but the disruption caused by modifications to the equipment must be kept to a minimum.
To enable the operators of Meadowhall Shopping Centre to accurately monitor the energy used by the new systems, the incoming sections of the switchboards are equipped with Schneider Electric Powerlogic microprocessor based power meters.
The power meters provide facilities for monitoring voltage, phase currents, real and reactive power, power factor and energy usage, while the PM800 units add functions for measuring total harmonic distortion of the current and voltage waveforms as well as measurement of the neutral current. The meters interface with the shopping centre’s building management system (BMS), and also provide pulse outputs for kWh measurements.
In order to minimise wasteful reactive power consumption by the new systems, Schneider Electric also supplied a Powerstyle automatic power factor correction panel. Providing connections between the LV boards and the power factor correction panel presented a second significant challenge, as the headroom above the boards for the connections was insufficient to accommodate conventional 1,250A cables and their associated cable trays. A convenient and cost effective solution was implemented by using Canalis busbar trunking which has compact dimensions, and which requires minimal space around it.
Further distribution facilities were provided by a Standard Plus QBU I Line panel board that offers an economical yet fully customised solution for the project. This board includes metering, contactors, power factor correction and an automatic changeover function for use with the site’s standby generator.
