Water and Effluent Treatment Magazine
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are automatically opened and remain open until the 11kv sup- ply has been restored. Temperature Once restored, all of the circuit breakers close in a timed sequence to re-energise the net- work. Due to the lack of a single control room, once the circuit breakers are tripped, they each go through a pre-programmed countdown procedure so that the circuits close at a pre-deter- mined phase, allowing voltage to grow at a controlled pace. Once the automation sequence is started, all switches should have operated aer 225 seconds (3min 45 seconds). This has been proven to re- power the circuit, without any further disruption. Lucy Electric also ensured that the onsite RTUs were fitted with high temperature batteries to ensure that they lasted their full ten-year life, as any temper- ature more than 25oC may cause premature failure of the battery (which is supplying the protec- tion). Also a battery and AC mains monitoring indication was added and connected back to the control centre to inform of Once the circuit breakers are tripped, they each go through a pre-programmed countdown procedure "This is the kind of project that we excel at" John Griffiths, Lucy Electric Vacuum and Pressure Solutions for Water and Wastewater Applications Low Energy Consumption Green Technologies Low Lifecycle Costs Gardner Denver Ltd Claybrook Drive, Washford Industrial Estate Redditch, Worcestershire B98 0DS, UK Tel. 01527 838200 | Fax. 01527 521140 tive ramifications. Under normal circum- stances, Lucy Electric would use its expertise to develop a remote automation solution. However, to further complicate the nature of the project there is little mobile coverage in the area around the treatment plant, so a traditional automation solution was not an effective option. Lucy Electric developed a solution that required an upgrade to the physical switch- gear equipment plus a bespoke switchover programme that would prevent the switches from tripping in the case of an outage. A new 11kv Ring Main Unit (RMUs) as well as new switch- gear, all designed and manufac- tured by Lucy Electric, were installed to the site. Existing switchgear and electrical distri- bution equipment were retrofit- ted so that each of the substa- tions was now supported by two RMUs and one control box. This ensured that the equip- ment was better able to cope with the bespoke sequencing programme Lucy Electric devel- oped to allow for the transform- ers to undergo a staged re-ener- gisation of the ring in case of a power outage. The new sequence was designed to run through three substations and six switches in total, however, due to the lack of mobile reception, there was no possibility of direct communica- tions to the control room from the switches. To resolve the problem, upon sensing the loss of the 11kv supply, the switches JANUARY 2015 WET NEWS 17 issues with a particular RTU, thereby allowing the controllers to predict issues ahead of any problem occurring. The company's innovative bespoke sequencing system and products provides Sutton and East Surrey Water with added piece of mind that the water treatment plant will be able to continue operation during times of maintenance or external power outage. This ensures pub- lic safety and protected reve- nues for the client. Minimum impact As a result of the project, a Sut- ton and East Surrey Water spokesperson says: "Lucy Elec- tric's product range and sequencing solutions have ensured that we can stay opera- tional with a minimum impact in the case of an external fault. This gives us piece of mind and will also save costs. The ability of the Lucy Electric team to come up with such an innova- tive and effective solution has made a significant difference to our business". Lucy Electric chief executive officer John Griffiths said: "This is the kind of project that we excel at. The complicated nature of the project, including the lack of remote mobile signal, meant that we had to develop some- thing truly tailored for Sutton and East Surrey Water. Our tech- nical expertise and our capacity to produce bespoke equipment for our clients mean that we have developed an innovative and effective solution for Sutton and East Surrey Water."