Level of Intervention:
Pump level AND Plant level / pumping station
Canal and River Trust owns and maintains 76 pumping stations throughout the canal network which either abstract water or transfer water (including back pumping) around the network. These pumping stations currently contain 122 individual pump sets.
- 25 of these pumps (33%) are used for water abstraction from river or groundwater sources to supply water to the receiving canal.
- 48 of these pumps (63%) recirculate or back pump water which has been displaced by boat traffic travelling through a lock or series of locks in a lock flight. They are also used to transfer water to a higher canal pound to accommodate water loss through seepage, evaporation and transpiration or for onward transfer to another length of canal.
- 3 of these pumps (4%) are used for flood water transfer and alleviation, to clear silt from locks, to pump sewage to sewer, and to pump surface water under specific agreements.
The Trust utilise Variable Speed Drives (VSD’s) at 13 sites and Smart power metering at all 76 sites
Pumps are selected from a range of manufactures including Flygt, Sulzer and KSB. They range in motor size from 10kW to 250kW. Typical flow rates across all stations are between 0.06 m3/s to 1 m3/s
Pumping stations are typically operated in three ways depending on the age of equipment, operational or environmental constraints and funding available for upgrade.
- 18% ‘Old set up’ – Manual operation and labour intensive.
- 6% ‘Intermediate set up’ – Semi-manual operation, some use of timer clocks.
- 73% ‘Fully automated’ – SCADA controlled, pumps start when set water levels are reached.
Fully automated is becoming standard practice – allowing remote performance monitoring, diagnostics, and the ability to adjust control parameters to match resource requirements.
The Trust has gradually upgraded pump sites/operations to incorporate SCADA systems.
Aim of the Experience:
2 distinct topics emerging of interest that we aim to improve our knowledge about are:
HARDWARE – More robust and reliable mechanical infrastructure (inc pumps) and instrumentation
SOFTWARE – Improved Control Panels and ease of SCADA integration (see Case Study **)
Hardware has a current average life span of 17 years (based on 2012-17 pump replacement installations) This is shorter where poor design and models were selected, and operational conditions not suited to the selected solutions.
Pump replacement and/or early intervention is often key before unplanned or catastrophic failures cause bigger / wider / costlier problems (23 out of 38 pump replacement projects between 2012 and 2017 were due to unplanned failures so earlier replacement would have save much expense)
Costs of overhauling failed hardware has increased in recent years whilst replacement costs have fallen – so this is now often the favoured solution. More up to date equipment can be installed and given that submersible pumps are relatively simple to replace, needing limited site works and having fewer operation impacts such as closed waterways.
Flow meters and Variable Speed Drives (VSD’s) need replacing as they start to age. This may require excavation of existing equipment, chamber construction and modifications to pipework. High civil engineering costs can be barriers to early / earlier replacements.
Description of the experience:
Trial solutions and through expert exchanges find best practices. Including:
- How to enhance older pumping equipment to provide maximum efficiency.
- How to integrate new pieces of equipment into existing infrastructure, a common approach and validate new tools which will have significant benefits.
- Jointly develop a tool kit to allow multi pump manufacturer comparisons (currently manufacturers tools are for their own ranges and specialist pump design software is geared towards new build rather than re build / development)
Assess typical pumping failure types and what problems these cause:
- Blockage due to vegetation debris, mechanical failure, electrical failure. (Overload)
- Low / erratic flow and reduced / poor flow presentation due to blocked intake screens or siltation build up. (Flow)
- Overheating due to lack of water around pump body causing blocked intake screens (Thermal)
- Mechanical failure of bearing seals allowing to water to leak from the pump volute to the motor pump seal (Leakage)
(The Trust has had problems with both the above and whilst both are covered by preventative and reactive maintenance contracts – these are costly and any efficiencies we can introduce through Green WIN will reduce overall running costs)
Test improvements (in Liege test tank and in situ) that deliver pump system efficiencies:
- Testing variable speed drives (VSD) that enable variation in the speed of the pump motor and allows adjustment in power consumption to fine tune a pump to its best efficiency point (BEP).
Assessing pumping stations to check suitability for VSD installation (not all pumps or systems are suitable for VSD equipment).
Summary of measures:
Efficiencies and good/best practice will be found through
- expert assessments provided by partner exchanges and technical expertise from Arcadis
- pump efficiencies found through testing in the Liege Test facility and
- in situ trials in the UK at Tinsley, Seend, Caen Hill and Calcutt
Specific targets are (later we can change to ‘were’) to develop
- Simple pump system design and evaluation tool. Geared towards waterways rather than sewage. Understanding how compromised design is affecting pump performance and life span
- We are looking for solutions to not only pump selection but other enhancements to design which can mitigate trash issues. (Trash and debris handling is a significant challenge and affects nearly all our stations)
- VSDs cost benefit analysis and better understanding on compatibility with different pump manufacturers. Look at the importance of BEP matching. Harmonic impact and effect on ‘weak’ supplies. Evidence of bearing failure following the use of VSD.
Supply load balancing to grid with variation in speed control and stop start. True cost benefit and impact on service life needs investigating.
Estimate of CO2 reductions and other outcomes: