Bristol Water cuts power bill by modernising plant with APDS and ABB Drives and Motors

Industry: Water

Application: Clean Water Pumps

Challenge:

Bristol Water was concerned to improve the energy efficiency of its pumping equipment at its Purton pumping station. Jim Reckhouse, Engineering Manager Bristol Water, says. “The original pumping equipment had been installed in 1963 and tests showed that it had fallen below a good standard of efficiency. A review of the site recommended new pumping plant that would be more suited to the duty we now have. This would see the pumps reduced in number from five to three and making them all the same size.”

The pumping station, which has a capacity of 70 megalitres per day, takes water from a canal and pumps it to a water treatment works downstream. The original installation used 3.3kV direct–on-line starters, which were unable to match flow to demand.

APDS Solution:

APDS installed two transformers, three new pump ends with ABB Eff1 high efficiency motors and three low voltage 400kW ABB industrial drives as part of a turnkey solution. These Drives were low harmonic drives to comply with the G5/4 regulations.

Doug Pitt of APDS says: “One of the biggest challenges of the job was that we always needed to maintain the ability to pump over the entire 15-month contract. We employed a specialist company to isolate the 3.3 kV supply and used temporary switchgear to maintain power to the 3.3 kV pumps.”

Benefits:

• Energy consumed by the site’s 40 mega litre pumps reduced from 560 kW to 240 kW
• Improvement in efficiency from 68 percent to 87 percent
• Better flow control, with flow matched to demand
• Automatic Drives Pump Load sharing
• New drives and pumps are low voltage
• Operators do not need high voltage experience

Conclusion:

Bristol Water now has better flow control and can match flow to demand. Says Jim Reckhouse: “Often we only need to run one pump. As demand increases and the first pump approaches full capacity, we switch in the second pump. The load is then shared equally between the pumps, with the first being slowed down and the second being speeded up to match it. The system also allows us to maximise the use of low-cost electricity at night. We do try to pump as much at night as we can, depending on the downstream capacity in the storage reservoir and raw water storage.”

Jim Reckhouse added “We were attracted to APDS because they clearly had the competence to do the job; were certified installers of ABB drives, which are quality drives; and also produced the lowest tender, we would certainly consider APDS and ABB for other similar jobs as using them has produced a good outcome for us at Purton.”

Footnote:

Please note these customer-approved stories are collected since 2000. While some company names may have changed during this time, the principles and methods described to save energy or improve productivity are applicable today. contact APDS Ltd Bristol: 01179 822 049 www.apds.co.uk