East Kerry North Nor th West Cork or k Project ro ject Substation Construction Methodology P E 687-F0272 687-F0272-R -R272 272-006 -006-000 -000
ESBI Engineering Solutions
Stephen Court, 18/21 St Stephen’s Green, Dublin 2, Ireland Telep Telepho hone ne+ +353353-11-70 703 3 8000 8000 Fax+ Fax+353353-11-66 661 1 6600 6600 www.esbi.ie
May 2012
File Reference:
P E687-F 687-F027 0272-R272-0 2-R272-006-0 06-000 00
Client / Recipient :
EIRGRID
Project Title:
East Kerry North West Cork Project
Report Title:
Substation Construction Methodology
Report No.:
P E687-F 687-F027 0272-R272-0 2-R272-006-0 06-000 00
Rev. No.:
1
Volume 1 of 1
Prepared Prepared by :
Eoin O’Mullane and Martina Kenny
APPROVED: TITLE: TITLE: Overhead Overhead Line Design and and Station Design Design
DATE: May 2012
Latest Latest Revision Revision Summary:
COPYRIGHT © ESB INTERNATIONAL LIMITED ALL RIGHTS RESERVED, NO PART OF THIS WORK MAY BE MODIFIED OR REPRODUCED OR COPIES IN ANY FORM OR BY ANY MEANS – GRAPHIC, ELECTRONIC OR MECHANICAL, INCLUDING PHOTOCOPYING, RECORDING, TAPING OR INFORMATION AND RETRIEVAL SYSTEM, OR USED FOR ANY PURPOSE OTHER THAN ITS DESIGNATED PURPOSE, WITHOUT THE WRITTEN PERMISSION OF ESB INTERNATIONAL LIMITED.
BF-REP-001-002-003
P E 687-F0272 687-F0272-R -R272 272-006 -006-000 -000
Change History of Report Date
New New Rev Rev
Aut hor
Summary of Change
P E 687-F0272 687-F0272-R -R272 272-006 -006-000 -000
Executive Summary The The pur purpose ose of this his d doc ocu ument ent is to out outlin line and and exp explain lain the con constru struct ctio ion n tech echniq niques which will be used on the East Kerry North West Cork Project. This document is intended to be used as an aid to understand broad OHL (line cable interface tower) and substation construction methodologies. This document should be read in conjunction with the Environmental Report.
Contents Executive Summary
i
1
Proposed Development
2
2
Substation Construction
3
2.1
Preparing the Site
3
2.2
Main Construction
3
2.3
Electrical Installation Including Transformers
4
3
4
Installation of Line Cable Interface Towers
5
3.1
Installation of Tower Foundations
5
3.1.1
Construction Equipment Required
6
3.1.2
Duration of Foundation Works
6
3.2
Erection of Tower Body
7
3.2.1
Construction Equipment Required
7
3.2.2
Duration of Tower Erection Works
7
Monitoring and Mitigation Measures
8
4.1
Ecology
8
4.2
Archaeology
8
4.3
Soils and Water
8
4.4
Construction Equipment Required
9
4.5
Traf Trafffic Man Managem agement ent
9
5
Waste Management
11
6
Reinstatement of Land
13
7
Summary
14
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1
Proposed Development The The prop roposed osed dev develop elopm ment ent in relat elatio ion n to the sub substat statio ion n com comprise rises s three hree mai main n elements:
Construction of a substation of 1,989m2 gross floor space comprising a two storey Gas Insulated Switchgear (GIS) 220/11 kV substation, including: a 220 kV substation building of approx. 1,055m2 gross floor space and up to approx. 14.2m in height; construction of a two storey 110 kV substation building of approx. 934m2 gross floor space and up to approx. 12m in height; associated outdoor electrical equipment, including 2no. transformers in transformer bays located between the 220 and 110kV stations, 2no. lightning protection masts (approx. height 14m and 1 no. SCADA pole approx. height 20m); associated internal access road, car parking areas (10 no. parking spaces), boundary treatment including 2.6m high station perimeter fencing, 1.4m high boundary fencing and other site development works; all within a site of approximately 5 hectares;
Construction of an associated access road of approx. 600m in length and generally 6m in width, from the public road to the substation, and including a new vehicular entrance onto said public road;
Associated localised modifications to the existing Clashavoon – Tarbert 220kV overhead transmission line (OHL) in order to loop this existing line into the proposed substation. These modifications consist of the removal of approx. 58m of the existing 220kV OHL and its replacement by 2 no. line cable interface towers (approx. height 21.5m)., and 2 x 220kV XLPE underground cables running inside the access road for approx. 500m connecting the proposed station with the line cable interface towers.
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2
Substation Construction P rior to commencement commencement of construction a detailed construction cons truction report will will be prepared to detail all the processes and procedures which will be undertaken as part of the construction of the East Kerry North West Cork 220/110kV substation. P rior to commencement commencement of work the the contractor(s) contractor(s ) will prepare prepare method method statements and work programmes programmes that show more more detailed phasi phasing ng of work. The appointed appointed contractor(s) will develop a series of detailed construction method statements for the construction construction of the substation. substation. These method statements statements will detail how the contractor plans to implement the design and will take into account access to the substation site and any archaeological, hydrological and ecological issues relating thereto. It will will also also take take into account account site site investigations, investigations, third party requirements, and mitigation measures outlined in the various sections of the environmental reports reports carried out prior to construction. The The meth ethod stat statem ement ents prod produ uced ced by the con contract ractor or(s (s)) will ill be agr agreed eed with ith the appropriate appropriate parties. parties. E irGrid/ES irGrid/E S BN will employ a team to monitor the the construction construction phase of the project and ensure works are being carried out in accordance with the agreed method statement, safety procedures, pollution control, etc. It should be noted that this construction methodology is indicative and based on ES B Networks Networks (ESBN) (ES BN) /EirGrid’s /E irGrid’s long long experien experience ce in similar similar project projects. s. Any issues specific to this project, for example unique planning conditions, will be incorporated fully into the appointed contractors’ scopes of work and careful supervision and management will be carried out to ensure full compliance. Below is an outline of the general construction activities associated with the substations. More specific details can be found in the Environmental reports.
The The con constru struct ctio ion n work ork will ill take ake place lace in three broa broad d phase hases: s:
2.1
Preparing the Site Site preparation is expected to take about 6 months and includes the following activities: (sequence to be agreed with ESB Networks/contractors and local authority prior to construction commencement)
2.2
Site entrance.
S ite establishment. establishment.
P ublic road modifications in accordance with the local authority's authority's requirements.
Construction onstruction of temporary temporary site drainage works.
Bulk earthworks, including site levelling and entrance road construction.
E xisting xisting OHL enabling enabling works. works.
Main Construction The The mai main n civ civil wor work ks are are exp expect ected to tak take e app approx roximatel ately y 8 mon montths an and incl inclu udes the following: (sequence to be agreed with ESB Networks/contractors prior to construction commencement) 3
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2.3
110kV and 220kV GIS Buildings, including foundations works, structural steelwork erection, cladding and building finishing works.
Construction onstruction of transformer compounds. compounds.
Access road and bridge construction.
Erection of line cable interface towers (x 2).
Permanent foul and surface water drainage works.
Paving.
Fencing.
Completion ompletion works.
Electrical Installation Including Transformers The The ele elect ctrrical ical inst instal alla lattion ion is is exp expect ected to tak take e ap approxim oximatel ately y 6 mont onths (dep (depen endi din ng on contracts with ESB Networks) and includes the following:
Delivery and installation of two 220/110kV transformers. These are unusually large and the deliveries will be managed in accordance with regulations governing the movement of large loads.
Delivery and installation of all other HV equipment.
Wiring and cabling of HV equipment and protection and control cabinets.
Comm ommissioning issioning of all newly installed equipment. equipment.
For the duration of the construction phase of the substation there will be temporary welfare facilities installed. Normal working hours will be adhered to for the most part, however there may be some occasions where work will be undertaken outside of these hours. These occasions will be kept to a minimum. Any works or deliveries which are likely to have a significant impact in terms of noise or other disturbances will be avoided outside of normal working hours. The activities which is expected to have most impact during this construction is the traffic to and from the site. A traffic management plan will be implemented to mitigate against undue impacts.
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3
Installation of Line Cable Interface Towers
3.1
Installation of Tower Foundations The The tow tower er sit sites es wil willl be ch check ecked for for un underg ergroun ound ser services ices such such as as cable cables, s, wat water pipes etc. If field drains are encountered encountered these these will be divert diverted ed and all diversions diversions identified to the landowner. The The tow tower er wil willl be set set ou out and and peg pegg ged pr prior ior to to fou foundat dation ion exca excav vatio ation n. This This may may require excavation of some existing ditches or drains to allow clear pegging of each individual leg footing footing for for excavation. excavation. All s such uch removals removals are restored upon upon completion of foundation works works.. It should should be noted that pre-construction pre-construction site investigations may show that ground conditions unsuitable to the standard foundations foundations are present. In this case a modified, modified, special foundation will be designed. A larger footing footing may may be required in the case of weak soils, soils , pile foundations may be required in the case of deep bog and reduced footing size foundations may be required in the case of rock being encountered at shallow depths. The The tow tower er stu stubs (low (lower par partt of of tow tower er leg leg)) wil willl be con concr cret eted ed in into th the grou groun nd. For F or each leg of the tower (4 in total) a foundation is excavated using a tracked excavator and the formation levels (depths) checked by the on site foreman. Each of the four corners of the tower will be separately anchored below ground in a block of concrete as per Figure 3.1 below. Any water in the excavation is pumped out prior to to any concrete being poured poured into the the foundation. foundation. Concrete trucks trucks shall be brought as close as possible to the excavation to pour directly into the excavation. In the event of this not being possible concrete shall be transported in dumpers, in the event that the ground is very poor and wheel dumpers will not transport the concrete over the terrain, track dumpers may be used. In areas of poor ground or high water table it may be necessary to use sheetpiles supported by hydraulic frame(s) to prevent collapse of the sides of the excavation and also to prevent the excavation excavation becoming too large. During any dewatering dewatering activities a standard water filtration system will be utilised to control the amount of sediment in surface water runoff. After this, the remaining part of the foundation, the concrete shear block or neck is formed using shuttering. During each pour the concrete shall be vibrated thoroughly using a vibrating poker. In the event that sheet piles have been used these are removed (pulled) at this stage. Care is taken not to damag damage e the the base mem members bers of the the tower. tower. The shear shear block formers are removed at this stage. The The towe ower found oundat atio ion ns are are back backffille illed d one one leg leg at a time with ith the exca excav vated ated mater ateria ial. l. The The back backffill ill is place laced d and and com compact acted in lay layers. ers. All dim dimensi ension ons s are are chec check ked following the the backfilling process. process. If the excavated excavated material material is deemed unsuitable unsuitable for backfilling imported fill material may be used also compacted in layers. When the base construction crew leave site they shall ensure to remove all surplus materials from the site including all unused excavated fill. Once the tower base is completed and fully set (usually after seven days) it is ready to receive the tower body which is normally constructed in an area near he foundation site ready to be lifted and bolted into place.
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Figure 3.1 3.1:: Photograph of a typical tower base with excavations.
3.1.1
3.1.2
Construction Equipment Required
4x4 vehicle
Concrete vibrator vibrator
Tractor and trailer
Water pump
Wheeled dumper or Track dumper (6 to 8 tons)
Timber or other Shuttering boxes
360 tracked excavator (13 ton normally, 22 ton for rock breaker).
Transit van
Chains and other small tools
Concrete delivered by supplier to closest convenient point (38 ton gross)
˚
Duration of Foundation Works
The The aver averag age e duration of foundation works is as follows:
Line Line Cable Interface Tower
6-10 days
P iled foundation foundation
10 days
Crew size size
4 to 6 workers
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3.2
Erection of Tower Body The The stee steell for the the remaind ainder er of the tower ower is deliv elive ered red to the sit site by lor lorry and and various sections of the tower, depending on weight and method of construction of the tower, are pre assembled on the ground beside the tower before lifting and bolting into into position. The tower is norm normally ally lifted using a suitable all terrain terrain (or Gin pole) crane.
3.2.1
3.2.2
Construction Equipment Required
4x4 vehicle
Winch
Tractor and trailer
Crane
Teleporter
Transit van
Chains an other small tools
Duration of Tower Erection Works
The The aver averag age e durat uratio ion n of tower ower build uildin ing g work orks is is as as fol follo low ws:
Line Line Cable Interface Tower
4 days
Crew size size
7 workers
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4
Monitoring and Mitigation Measures The The follo ollow wing ing sect sectio ion n provid ovides es the main ain form orms of monit onitor orin ing g and and mitig itigat atio ion n measures which are proposed for the project. Reference to individual Environmental Reports should be made for specific details of mitigation measures proposed for individually identified sensitive sites.
4.1
Ecology The The follo ollow wing ing are are the mitig itigat atio ion n measu easure res s which ich will ill be carr carrie ied d out out during ing construction:
4.2
Specific mitigation measures as outlined in the Ecology report.
Hedgerows: re-planting with broadleaves and component species.
Watercourses: follow guidelines set by the former Regional Fisheries Board and approved by the Inland Fisheries Ireland (IFI).
General: Following the recommendations in the environmental report, a site appropriate, E Environm nvironmental ental Management Management Plan P lan will be agreed before construction works.
Archaeology The The follo ollow wing ing are are the mitig itigat atio ion n measu easure res s which ich will ill be carr carrie ied d out out during ing construction:
4.3
Specific mitigation measures as outlined in the Cultural Heritage E nvironmental nvironmental Report Report..
Monitoring of site works in accordance with advice from the (Department of Arts, Heritage and the Gaeltacht (DAHG) is recommended.
In accordance with the the Code Code of Practice P ractice between between EirGrid EirG rid and the the Minister of the Environment, Community and Local Government in relation to Archaeological Heritage (2009) a project archaeologist will be appointed to oversee the project.
Soils and Water In accordance with the recommendations of the soil and geology and hydrology reports in the Environmental Report:
Machinery during the construction phase will be managed to ensure that its access is limited to one entry and exit point.
Minimise time for excavations being open as far as possible.
During any dewatering activities a water filtration system will be utilised to control the amount of sediment in surface water runoff.
Removal of vegetation will be limited to the area of excavation.
The locally excavated material will be reinstated immediately following construction to allow recovery of any potential groundwater level change as quickly as possible. 8
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Aggregate will be imported rather than quarried on site.
The contractor will be required to make provision for removal of any concrete washwaters, most likely by means of tankering off-site and no such washwaters washwaters will be discharged to groundwater. groundwater.
Soil stockpiles will remain undisturbed until re-use and reestablishment at the site.
In order to reduce the risk of contamination arising as a result of spills or leakages, measures include, but are not limited to, the following:
Storing fuels, chemicals, liquid and solid waste on impermeable surfaces.
Undertaking refuelling of plant, equipment and vehicles on imperm impermeable surfaces.
Ensuring all tanks and drums are bunded in accordance with established best practice guidelines.
P rovision of spill kits at high risk sites.
Re-fuelling of construction equipment and the addition of hydraulic oil or lubricants to vehicles/ equipment will take place in designated bunded areas within the main construction compound. A drip tray will be used beneath the fill point during refuelling operations in order to contain any spillages that may occur. Spill-kits and hydrocarbon absorbent packs will be stored in the cabin of each vehicle and operators will be fully trained in the use of this equipment.
4.4
4.5
Construction Equipment Required
4x4 vehicle
Wheeled dumper or Track dumper (6 to 8 tons)
360 tracked excavator (13 ton normally, 22 ton for rock breaker)
Transit van
Teleporter or other mobile aerial platform and lifting equipment.
All terrain crane (depending on site)
Chains and other small tools
Road material delivered by supplier to closest convenient point (38 ton gross)
Crew size: size:
˚
Generally 3 workers
Traffic Management A traffic management plan will be agreed with Kerry County Council for the duration of the works. Traffic Management will be in accordance with the details contained in the Environmental Report and recommendations of KCC. Construction traffic will comply with the local traffic requirements and in agreement with Kerry County Council road engineers.
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Traf Trafffic Sign Signs Man Manual issu issued ed by the Dep Depart artment of the Envir Environ onm ment ent prov rovides ides details of the traffic signs which may be used on roads in Ireland, including their layout and symbols, the circumstances in which each sign may be used and rules for positioning them. Chapter 8 of the 1996 Traffic Signs Manual will be used on this project.
Local groups will be consulted in advance of works: eg. local schools (bus routes) and local residents. Dirt on roads; If required, a wheel-wash shall be installed within the temporary works compound to wash dirt from the wheels of road trucks transporting spoil off site. The access route shall be monitored to ensure no dirt accumulates on the public road due to the construction traffic and cleaned if required.
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5
Waste Management All waste arising during the construction phase will be managed and disposed of in a way that ensures the provisions of the Waste Management Act 1996. A Construction onstruction Waste Waste Management P lan will be implemented implemented to minimise minimise waste and ensure correct handling and disposal of construction waste in accordance with the Best Practice Guidelines on the Preparation of Waste Management Plans for Construction and Demolition Projects, Department of the Environment, July 2009.
Waste Manager
A member of the construction tem will be appointed as waste manager for the construction phase. The waste manager will have overall responsibility to oversee, record and provide information to the relevant authorities on waste management for the project. Authority will be given to the waste manager to delegate responsibility to sub-contractors where necessary and to coordinate with suppliers, service providers and sub-contractors to prioritise waste prevention and salvage. The The wast aste manag anager er will ill be train rained ed in how to set set up and and main aintain ain a recor ecord d keep eeping ing system, how to perform an audit and how to establish targets for waste management on site. He/she will be also be trained in the best methods for segregation and storage of recyclable materials, have information on the materials that can be reused on site and know how to implement a project specific waste management plan.
Waste Types Bedrock
If bedrock is encountered during excavations, it will either be crushed onsite and used for infill during construction, or be removed from the site by licensed contractors under the Waste Management Act 1996 and subsequent amendments, Waste Management (Facility (F acility Perm P ermit it & Registrat Registration) ion) Regulations R egulations 2007, 2007, and the Waste Management (Collection (Collection Perm P ermit) it) Regulations Regulations 2007 2007 and disposed of off-site. off-s ite.
Soil/Subsoil
Soil will be removed during excavation of the foundation areas. Excess inert soils and subsoils excavated that is not required for use as fill on site following discussions with the landowner, will be disposed of or re-used offsite.
Any soil removed from off-site will be carried out by contractors licensed under the Waste Management Act of 1996 and subsequent amendments, the Waste Management Management (Facility (Facility Perm P ermit it & Registr Registration) ation) Regulations Regulations of 2007 and the the Waste Waste Management Management (Collection (Collection Perm P ermit) it) Regulations Regulations of 2007. The volume of waste removed will dictate whether a certificate of registration, permit or licence is required.
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If any soil/subsoil is deemed to be contaminated it will be stored separately to the inert soil/subsoil, sampled and tested. The material will be appropriately classified as non-hazardous or hazardous in accordance with EU Council Decision 2003/33/EC which establishes the criteria for the acceptance of waste at landfills, before being transported to an appropriately licensed facility by permitted contractors.
Metal
Metal is highly recyclable; there are numerous companies that will accept these materials. A segregated skip will be available in the site compound for storage of metals from site pending recycling.
Hazardous Hazardous Materials Materials
During actual construction activities, on-site storage of any hazardous wastes will be minimised, with refuelling and oil changes carried out on a regular basis off site. In the unlikely event of any storage of all hazardous wastes on site, this will be undertaken so as to minimise potential for environmental impacts.
Non-Recyc Non-Recyc lable Waste
All non-recyclable wastes will be transferred to the site compound at the end of the working day. In the site compound there will be a general skip or other receptacle provided for non-hazardous waste not suitable for reuse or recycling. This This skip skip will ill in includ clude e ge genera nerall wet wet wast aste (m (mixed ixed food ood was wastte an and foo food d pac pack kagin aging g), polystyrene, polystyrene, contaminated contaminated cardboard, contaminated contaminated plastic etc. P rior to removal, the receptacle will be examined by the waste manager to determine that recyclable materials have not been placed in there. If this is the case, efforts will be made to determine the cause of the waste not being segregated correctly.
Tracking Tracking and documentation procedures for off-site waste
All movement of waste and the use of waste contractors will be undertaken in accordance with the Waste Management Act 1996, Waste Management (Facility Permit & Registration) Regulations 2007, and the Waste Management (Collection Permit) Regulations 2007. This includes the requirement for all waste contractors to have a waste collection permit issued by local authority where the majority of the contractors business takes place.
If the waste is being transported to another site, a copy of the waste permit or EP A Waste Waste Licence Licence for that site must must be provided to to the waste waste manager. manager. If If the waste is being shipped abroad, (in this unlikely event) a copy of the Transfrontier Shipping (TFS) document must be obtained from Dublin City Council (as the relevant authority on behalf of all local authorities in Ireland) and kept on site along with details of the final destination (permits, licences etc). A receipt from the final destination of the material will be kept as part of the waste management records.
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Reinstatement of Land Once all works are complete, the access route and the construction areas around the substation substation are restored restored to to their original condition or better. better. Generally this work is carried out by a specialised agricultural contractor and is carried in accordance with the relevant IFA agreements and in consultation with the individual landowner.
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Summary Construction of the East Kerry North West Cork Project can be summarised as follows:
The substation construction activities will take place at a fixed construction site
Work will only be carried out during normal working hours.
All planning conditions will be implemented and contractor will be supervised and managed closely to ensure full compliance.
Duration of work at East Kerry North West Cork substation will be approx. 12-18 months.(Subject to agreement post-planning with contractors and ESBN)
Note: This document should be read in conjunction with the overall Environmental Report and its specific recommendations for the East Kerry North West Cork Project.
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