Case Studies

History of Dobbies / Southport –

Dobbies Management believed additional power savings were possible. They had conducted in-depth research over a 12 month period and decided in 2009 that Power Optimisation was an option to consider.

Their Parent Company, Tesco, had also carried out a number of trials with Power Optimisation systems. An initial trial has prompted Tesco to purchase a powerPerfector step-down transformer. When Tesco realised that Dobbies was looking for similar equipment, Tesco recommended powerPerfector.

Dobbies decided to carry out an independent assessment of the products available; and invited the following product companies to present their products and provide quotations (based only on sight of power bills) during the months of May to June 2009 :

a) powerPerfector, b) PowerStar, c) Active Energy Powermaster, d) Powersave (Claude Lyons), e) Voltmaster, f) PropSava – just launched in the UK

After analysis of all the products and quotations presented, David Clark, Dobbies Construction Development Manager, and his engineering staff chose the PropSava on 6th September 2009.

David Clark is reported to have said “We chose the PropSava for a number of reasons. Our main priority as a Company is the safety of our customers and staff. The PropSava was the only product that had automated and manual by-pass systems. In the event of any problems, external or internal, the PropSava switched over to main power without interruption to the services and systems. The second reason was that the PropSava was a voltage regulator and stabiliser. It is capable of lowering or increasing the voltage automatically to deliver a stable power output. All the other products were step-down transformers that would only operate in one direction which was down. This was a serious concern for us. We have our own sub-station which normally delivers higher than average voltage but there have been a number of times over the last 18 months where the grid voltage has dipped alarmingly. On one occasion this very low voltage caused severe damage to our chillers. We therefore believed that a product which would continue to lower voltage to ever dangerous levels would not be acceptable. The PropSava was competitively priced; which is important not only for our return on investment, but also for the cost implications on a roll-out to 25 other stores. We initially had reservations on being the first installation in the UK of an unknown company and product. However, after investigation, we confirmed that Vanguards factory in Shanghai has actually been building this type of equipment for over 15 years.”

In late August 2009 we asked Dobbies for an indication of the other competitors pricing. We were only provided one competitor price. Here are the costs and savings as stated in both proposals.

September 21st to the 27th was selected by Dobbies – Southport as a representative week to carry out the 7 days of logging the power quality. Following analysis of all readings, it was confirmed that a 360KVA PropSava SCR System should be installed with a specification of:

Confirmation of final specifications was received by Vanguards Power on the 24th September 2009. PropSava 360KVA was designed, built and completed testing on the 28th October 2009. The PropSava was then packed and shipped from Shanghai on the 22nd November 2009, arriving at Felixstowe on the 15th December 2009. Due to snow storms the PropSava was put into storage over Christmas and was delivered to Dobbies on the 7th January 2010. Regrettably the snow storms arrived again and several new installation dates cancelled. The installation was postponed until the 22nd January 2010. The PropSava was activated on the 23rd January 2010.

On the 29th January 2010, Dobbies – Southport electrical contractors installed a new heating and cooling system. On the following day 30th January, there was a catastrophic failure of this heating system; causing extensive damage to the heating system and an overload of the sites electrical system. For some reason the Distribution Board RCB did not isolate the faulty circuit (later found to be faulty). Fortunately, the PropSava automatic By-Pass System shut down the power to the effected phase; isolating this circuit to prevent additional damage to the sites electrical equipment; and provided power to the rest of the building on the other two phases.

The PropSava only suffered one blown protection fuse system (thyristor); but all 3 thyristors were replaced.

Following an investigation by Dobbies – Southport, the electrical contractors were dismissed; as was the entire heating and cooling system. It was then found that the site had many other electrical “problems”. Dobbies – Southport undertook a complete inspection with new electrical contractors and made the necessary repairs. This work took 3.5 months to complete. It was agreed that during this time the PropSava would remain on By-Pass until the sites problems had been rectified. All was completed on the 10th May 2010 and the PropSava was switched to Regulation and Commissioned on the 14th May 2010.

Photos of Installation and Commissioning –