EDS 07-0020 Civil Requirements for new
Document Number: EDS 07-0020 Date: 26/03/2015 ENGINEERING DESIGN STANDARD EDS 07-0020 CIVIL REQUIREMENTS FOR NEW CUSTOMER SUPPLIES AND GENERATION CONNECTIONS Network(s): EPN, LPN, SPN Summary: This standard provides guidance on the Civil and Building services requirements for substations and switchrooms constructed by customers and developers to accommodate equipment to be installed or adopted by UK Power Networks. Owner: Mark Dunk Date: 26/03/2015 Approved By: Steve Mockford Approved Date: 31/03/2015 This document forms part of the Company’s Integrated Business System and its requirements are mandatory throughout UK Power Networks. Departure from these requirements may only be taken with the written approval of the Director of Asset Management. If you have any queries about this document please contact the author or owner of the current issue. Applicable To UK Power Networks External All UK Power Networks G81 Website Asset Management Contractors Capital Programme ICPs/IDNOs Connections Meter Operators HSS&TT Network Operations UK Power Networks Services Other THIS IS AN UNCONTROLLED DOCUMENT, THE READER MUST CONFIRM ITS VALIDITY BEFORE USE Version: 3.0 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 Revision Record Version 3.0 Review Date 11/07/2016 Date 02/02/2015 Author Mark Dunk Why has the document been updated – Update and clarification of information What has changed - Section 1 - Introduction updated to provide greater clarity of the use and application of this document. Section 4 updated to clarify requirement for separate rooms for Customer and UKPN equipment. Section 5.7.1 updated to clarify security rating and heavy duty doors stay requirements. Document title amended. Version 2.0 Review Date 11/07/2016 Date 26/02/2015 Author Mark Dunk Why has the document been updated: Updated to include drawing EDS 07-0020-04 What has changed: Addition of drawing EDS 07-0020-04 and references updated in document. Version 1.0 Review Date 11/07/2016 Date 19/06/2013 Author Mark Dunk © UK Power Networks 2015 All rights reserved 2 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 Contents 1 Introduction ............................................................................................................. 4 2 Scope ....................................................................................................................... 4 3 Glossary and Abbreviations ................................................................................... 5 4 General Requirements ............................................................................................ 5 5 Technical Requirements ......................................................................................... 6 5.1 Building Construction................................................................................................. 6 5.2 Switchgear Base Construction ................................................................................... 6 5.3 Flood Risk ................................................................................................................. 7 5.4 Fire Risk .................................................................................................................... 7 5.5 Environment .............................................................................................................. 7 5.5.1 Facilities Required for Indoor Extensible Switchgear ................................................. 8 5.5.2 Facilities required for Ring Main Unit switchgear ....................................................... 8 5.5.3 Building Services ....................................................................................................... 8 5.6 Access....................................................................................................................... 9 5.7 Security ..................................................................................................................... 9 5.7.1 Doors ........................................................................................................................ 9 5.7.2 Locks ....................................................................................................................... 10 6 Drawings ................................................................................................................ 10 7 Earthing.................................................................................................................. 11 8 References ............................................................................................................. 11 © UK Power Networks 2015 All rights reserved 3 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 1 Introduction The purpose of this Engineering Design Standard and the associated drawings is to provide guidance for civil and building services requirements to internal and external designers, ICPs, customers and contractors who need to provide accommodation for UK Power Networks incoming supply and related auxiliary equipment for customer electrical supplies at voltages from 6.6kV to 33kV. This Design Standard is only applicable to structures provided by customers to accommodate UK Power Networks’ owned or adopted equipment installed to afford an electricity connection to a customer. It is anticipated that the building or housing will remain in the ownership of the customer, who shall maintain it in good condition and ensure that it is fit for its intended purpose. Where it is specified in the connection agreement that UK Power Networks are to adopt and/or are responsible for the maintenance and repair of the building and structural assets, all building and structural works shall be designed, specified and constructed in accordance with EDS 07-0105 Grid and Primary Substation Civil Standards. 2 Scope This document is intended to provide general guidance for the construction of buildings or housings suitable to accommodate all of the supply-side equipment required for customer demand or generator connections at voltages between 6.6kV and 33kV to networks owned by UK Power Networks. It is not intended that any customer owned equipment shall be installed in the chamber used to accommodate equipment owned by, or to be adopted by, UK Power Networks with the exception of the cables connecting to the customer’s installation.The equipment footprint and any support designs shown in the associated drawings have been produced for use with specific equipment types. It is intended that the designs may be modified or adapted where necessary to suit switchgear of other types and manufacturer, provided that the switchgear to be installed is of a type approved for use by UK Power Networks and the general clearance and access principals are met. All works designed for adoption by UK Power Networks, under the provisions of ENA ER G81 ‘Framework for Competition in Connections’, will need to have written approval from UK Power Networks design staff prior to commencement of construction. The external appearance of the building and the type of construction used shall be designed and constructed by the customer, or their appointed contractors, and will need to comply with any local authority planning and construction regulations; all planning and building consents are to be obtained by the customer. Approval from UK Power Networks for the switchroom building design team or Lead Designer should be obtained before the final planning application is made. © UK Power Networks 2015 All rights reserved 4 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 3 Glossary and Abbreviations Term Definition BSEN British Standard incorporating European Standard GRP Glass Reinforced Plastic RTU Remote Terminal Unit SCADA Supervisory Control And Data Acquisition U Value Measure of Thermal Conductivity UK Power Networks UK Power Networks (Operations) Ltd consists of three electricity distribution networks: (UKPN) 4 Eastern Power Networks plc (EPN). London Power Network plc (LPN). South Eastern Power Networks plc (SPN). General Requirements The building or housing for UK Power Networks owned or adopted equipment, wherever possible, shall be a free-standing structure constructed at a boundary location. The switchroom shall be accessible to UK Power Networks staff at all times from the public highway and be fitted with UK Power Networks standard locks or approved security system. Semi-detached buildings attached to a main structure or customer’s switchroom, but not integrated into the main building, may also be acceptable provided that access is not restricted. If no other alternative is available, e.g. due to space or planning restrictions, a switchroom at ground level, which is integrated into the larger building, may possibly be used provided that there is adequate and unrestricted access and is subject to agreement by the UK Power Networks Regional Design Manager. Locations above or below ground level shall not normally be considered, regardless of building configuration, for reasons of maintaining safety and control over operation UK Power Networks and Customer/Developer equipment must be located in separate rooms with their own separate access The Civil Designer shall consider all future maintenance requirements to ensure that future building maintenance will be minimal. Access restrictions and future risk to operational engineers is also to be considered. In accordance with the latest version of Construction (Design and Management) Regulations, the Designer shall consider the safe construction, access, maintenance, operation and demolition of the structure in addition to the installation and removal/replacement of all plant. © UK Power Networks 2015 All rights reserved 5 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 5 Technical Requirements 5.1 Building Construction All UK Power Network’s switchroom buildings or housings shall provide a robust, windowless, vandal-resistant and stable environment for the switchgear and ensure that equipment is not damaged by any environmental cause such as condensation, dust or other pollutants. There must be sufficient space for operator safety and all necessary auxiliary and operational equipment, including steps, where these are required to access operational equipment. The building or housing may be of traditional brick built, steel frame, or any other suitable construction type, and may include pre-fabricated GRP housings provided that the correct environment is established to ensure that the equipment installed is not damaged or put at risk in any way by environmental conditions. For all installations at 20kV and above and for 6.6/11kV installations where indoor extensible switchgear is used, the switchroom must provide a regulated indoor environment. The external walls of the building shall achieve a U value of 0.43W/m2K and, where practicable, all walls must be suitable to allow the secure fixing of wall mounted equipment and associated cabling. The details of roof construction are to be designed by a Structural Engineer employed by the customer, and may be subject to approval by the local planning authority and/or building control. The roof construction is to achieve a U value of 0.25 W/m2K. All designs will need to take account of the switchgear manufacturer’s requirements for overpressure venting and have a minimum floor to ceiling height of 3150mm, this may need to be increased depending upon the switchgear manufacturer’s requirements. 5.2 Switchgear Base Construction The concrete base, floor slab and walls are to be constructed to the customer’s design and will be subject to UK Power Networks approval. All concrete is to be grade C32/40 with a minimum content of 300kg/m 3 of Sulphate Resisting Cement to BS12, and maximum water/cement ratio of 0.6. The maximum aggregate size is not to exceed 20mm. A Visqueen 1200 gauge membrane (or equivalent) is to be provided beneath the floor slab, laid on 25mm of sand blinding, on a minimum 150mm thick, well compacted, sub-base. Reinforcement bar layouts are to be designed by the Structural Engineer employed by the customer. Reinforcing bars are to be fitted with two 70mm2 copper earth bond connections on diametrically opposite sides of the building with connections in the cable pit to enable connection to be made to the switchroom main earth bar. Reinforcing bars are to be electrically continuous across the building. Earth bonding joints to the reinforcing bar shall use the approved connection arrangements, as shown in UK Power Networks document EAS 06-0011, may be welded or may be sil-fos brazed. The reinforcement mesh is to be supported with proprietary chairs with a minimum cover of 50mm. The mesh is not to be trodden into the concrete surface. The straightness tolerance of the Unistrut foundation channels, which are provided by the customer, will be in the range of 1mm over a metre of channel length. The switchgear manufacturer’s installation instructions shall be consulted to confirm the required accuracy tolerance for fixing the switchgear. © UK Power Networks 2015 All rights reserved 6 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 5.3 Flood Risk All switchrooms and substation sites shall be adequately drained for the anticipated normal environment with precautions to prevent ingress of moisture. External ground/access road levels shall be designed such that there is no detrimental build-up of surface water in the proximity of the enclosure. The floor level of the switchroom should be constructed at a level of 300mm above the 1 in 100 river flood level or the 1 in 200 year tidal flood level, whichever is higher. A flood risk assessment shall be carried out, and switchrooms and substations should not normally be constructed in areas which may be subject to flooding with a greater risk than 1 in 100 year river flood level or 1 in 200 year tidal flood level. Information about flood risks is available on a postcode basis from the Environment Agency website. All duct and cable entries to the switchroom shall be sealed after cable installation using Tyco Rayflate duct sealing system (or equivalent) to prevent water or gas ingress into the building. Where there is no other option but to construct in an area known to have a higher flood risk than that quoted above, the guidelines in UK Power Networks document EDS 07-0106, which deals with flood precautions, shall be followed. It is not always possible to seal cable entry ducts such that they are 100% water-tight and seepage can cause pooling or standing water which can contribute to the corrosion of contacts within the switchgear leading to operational malfunction. In areas where a high water table has been identified it will be necessary to install a pump with which to remove water from the cable trench, the 230v pump should be constructed from stainless steel, float switch activated and able to discharge 110litres per minute at 2-3metre head. 5.4 Fire Risk The switchroom shall be included in the fire risk-assessment for the site and have a minimum fire resistance of one hour. Fixed or portable fire-extinguishing equipment shall not normally be fitted in UK Power Networks switchrooms. In the event that the local fire authority requires the fitting of an automatic fire suppression system to a building, if the system is fitted in the UK Power Networks switchroom, it shall be: 5.5 Suitable for high voltage electrical hazards; Fitted with external lockable isolation adjacent to the switchroom entry door; Designed by a fire suppression system specialist employed by the customer; Approved by the UK Power Networks designer. Environment Switchrooms designed for the installation of indoor extensible switchgear at 33kV, 20kV, 11kV, or 6.6kV or its controlling equipment, must have a controlled environment designed to prevent condensation forming in or around the equipment. In practice this will require the installation of heating and de-humidification with automatic control systems and alarm systems to be linked to the UK Power Networks SCADA system. Where there is a likelihood of other possibly harmful pollutants entering the switchroom, appropriate preventative sealing methods will be required. Switchrooms or housings used for outdoor ring main unit type equipment will not require heating or de-humidification equipment. It should be noted that UK Power Networks no longer installs and will not adopt metal clad 6.6kV to 33kV distribution substation equipment installed in an outdoor environment. © UK Power Networks 2015 All rights reserved 7 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 In addition to the HV/EHV Switchgear the following equipment as detailed in Sections 5.5.1 and 5.5.2 may be required, and the necessary wall/floor space is to be provided or allowed for as specified by UK Power Networks or by the switchgear manufacturer. 5.5.1 Lockable box or cupboard fixed to the wall for test bushings, test attachments, test devices and operational tools or handles as recommended by the equipment manufacturer. Sufficient wall or floor space to allow the fitting of: Tripping Battery, SCADA RTU, SCADA Battery (this may be integrated with the RTU) and pilot interface wall boxes for incoming and customer interface pilot terminations. External wall space may be required to fit a satellite dish aerial (this may require planning permission). Fixed platform steps to UK Power Networks specification where access is required to high level operational equipment such as relays. Note: operational equipment should not normally be fitted more than 1.5m above floor level where this can be avoided. Adequate lighting with a minimum of 500 lux maintained luminance with a uniform factor of 0.8 across the front and rear elevation for the whole the switchgear. Reliable Power Supplies for equipment and battery charging. SCADA equipment will be provided and installed by UK Power Networks where needed. 5.5.2 Facilities Required for Indoor Extensible Switchgear Facilities required for Ring Main Unit switchgear Lockable cabinet fixed to the wall or floor for Test Bushings, test attachments and operational tools, if not integral to the switchgear, as recommended by the equipment manufacturer. Sufficient space to allow the fitting of: Tripping Battery, SCADA RTU, SCADA Battery (this may be integrated with the RTU in some cases), and pilot interface wall boxes for incoming and customer interface pilot terminations. External wall space may be required to fit a satellite dish aerial (this may require planning permission). Lighting for access. Reliable Power Supplies for equipment and battery charging. SCADA equipment will be provided and installed by UK Power Networks where needed. 5.5.3 Building Services In all cases a secure LV AC electricity supply shall be provided by the customer for battery charging and other building services functions, (refer to EDS 08-0051 for the detailed requirements). The consumer unit for this supply shall be fitted in the UK Power Networks switchroom and all wiring shall comply with BS 7671. Cables, pipes or other services that are not required for connection in the switchroom shall not enter or pass though the building structure. The general requirements for the electrical installation are shown in the associated drawings EDS 07-0020-01 to EDS 07-0020-04. UK Power Networks drawing Number EDS 07-0102-16 shows the basic requirements for a GRP housing suitable for a Ring Main Unit with metering transformers. It should be noted that provision of lighting and power, and accommodation for control cable terminations will also be required. Suitable external provisions to house metering equipment adjacent to the GRP (no more than 5m distant) will also need to be added if this layout is adopted. © UK Power Networks 2015 All rights reserved 8 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 5.6 Access Once commissioned, the supply chamber shall only be accessible to persons who hold the necessary Authorisation under UK Power Networks Distribution Safety Rules. This will not normally include the customer’s staff. It is essential that all designs allow unrestricted access for equipment and UK Power Networks’ or their agents’ personnel. Designs shall cater for equipment delivery using a Large Goods Vehicle with a lorry mounted crane, and have a minimum width of 3.5m and height of 4m with an unloading area directly outside the switchroom doors. The access shall be designed to accept a minimum axle weight of 11 tonnes and an adequate turning bay if access is possible from one direction only. Access to replace faulty equipment, should the need arise, must be maintained at all times. 5.7 Security 5.7.1 Doors All doors are to be certified to minimum grade of SR2 in accordance with the latest issue of the Loss Prevention Board LPS 1175 specification, subject to site security conditions and location it may be necessary for SR4 rated doors to be installed. Standard security door cores are to be a minimum of 45mm thick flush double pan construction formed from 1.2mm nominal thickness zinc coated steel sheet to BSEN 10152 (BS 6687). Resin impregnated core material, or mineral wool core material is to be provided, and the whole construction is to be riveted, glued and welded, as required, to give adequate rigidity and performance. Doors are to be polyester powder coated generally in BS colour 14C39 green or as required for the local colour scheme which may be required by planning regulations. Each door leaf is to be hung on a minimum of three heavy-duty stainless steel hinges. Hinges are to incorporate 'dog bolt' protection or alternatively, three separate dog bolts are to be provided to protect the hinges. Adequate and suitable door restraints capable of holding the doors open at 90 degrees are to be fitted at the head of each door leaf, for doors taller than the standard 2240mm or doors of heavy duty construction will require heavier duty door stays. A security strip is to be provided to the leading edge of the doors to mask the gap between the doors or between the door and frame. External door sets shall be fitted with a suitable weather seal strip. The double door to the switchroom is to be fitted with a double panic bar with top and bottom shoot bolts and locking handle to suit UK Power Networks Europrofile lock barrel. The double door must achieve a minimum clear opening height of 3000mm to conform to switchgear manufacturer’s requirements. The necessary door height may vary according to the requirements of different manufacturers and a transom is to be allowed for where the delivery height exceeds that of the 3000mm door clear opening. Three metres height should be suitable for most equipment types but will need to be confirmed prior to construction. The single door to the rear of the switchroom is to be fitted with a panic bar with top and bottom shoot bolts and should not be fitted with an external handle or lock barrel. The single door to the metering room is to be fitted with a mortice sashlock, with round section external lever handle and escutcheon, and Europrofile cylinder with internal thumbturn to suit metering operator lock barrel. © UK Power Networks 2015 All rights reserved 9 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 All doors must have a minimum clear opening width of 750mm to facilitate emergency egress. Doors fitted to GRP enclosures will require UK Power Networks approval and must conform to the specification detailed above. 5.7.2 Locks The switchroom chamber is to be fitted with UK Power Networks standard locking, which will be supplied and installed by UK Power Networks, when the supply is energised. Where the switchroom is accessed via a gate in an external boundary, a dual locking system shall be installed to allow access to UK Power Networks staff by fitting a UK Power Networks standard security padlock. 6 Drawings Drawing Number Subject EDS 07-0020-01 33kV Metering Switch-house Using Siemens NXPLUS – Single Circuit EDS 07-0020-02 33kV Metering Switch-house Using Siemens NXPLUS – 3 Panel Loop EDS 07-0020-03 11kV Metering Switch-house Using Schneider Genie Evo – 3 Panel Loop EDS 07-0020-04 Standard Brick Enclosure for Customer RMU with Metering Panel EDS 07-0102-16 GRP Enclosure & Plinth Design for Metered RMU A number of generic footprint drawings have been produced to assist customers and ICPs with the design of switchroom chambers. The drawings numbered EDS 07-0020-01 to EDS 07-0020-04 have been produced for the indicative layout of specific types of switchgear, as shown on the drawings, and will need to be modified, or otherwise adapted, to accommodate other manufacturers and types, particularly with regard to fixings, supports, and switchgear main and auxiliary cable entry arrangements. UK Power Networks drawing Number EDS 070102-16 may be used as the basis for housing a ring main unit at 6.6 or 11kV, with the addition of 230 Volt electrical supplies, control cables and metering. The external design and appearance of the building will be decided by the customer but will need to comply with the local authority planning and building control regulations. Designers shall ensure that switchgear cable entry arrangements for main and auxiliary cables are adequate to permit safe and practicable termination of all cables. The requirement for external duct entries into the switchroom shall ensure that adequate provision is made for all incoming and outgoing circuits including control and communications cables and earth connections. The cable access arrangements shall allow a minimum bending radius of 1m for all 6.6, 11 & 33kV cables. All ICP or customer’s drawings will need to be approved in writing by the UK Power Networks designer before any construction work is commenced. © UK Power Networks 2015 All rights reserved 10 of 11 Civil Requirements for new Customer Supplies and Generation Connections Document Number: EDS 07-0020 Version: 3.0 Date: 26/03/2015 7 Earthing During the construction phase for the switchroom the customer shall install earthing connections for the incoming UK Power networks supply. In most cases this will require a copper earth conductor, with a minimum equivalent size of 70mm2 copper, but the conductor is to be appropriately sized for the prospective earth fault current related to the incoming supply, which may require larger sized conductors, particularly at 33kV. The earthing conductor should be installed around the outer perimeter of the switchroom with earth rod connections as near as practicable to each of the four corners. Materials used for earthing shall comply with UK Power Networks document EAS 06-0011 ‘Earthing Materials’. During the construction phase effective bonding of all metallic support work, cladding or other structural metal parts, including doors, is required using a minimum equivalent of 50mm2 copper conductor. The earthing shall be installed and tested by a specialist contractor and comply with EDS 060013 ‘Primary Substation Earthing Design’, EDS 06-0014 ‘Secondary Substation Earthing Design’ and EDS 06-0017 ‘Customer Installation Earthing Design’ as appropriate. The customer’s earthing survey report shall be used as the basis for the earthing installation. 8 References UK Power Networks documents EDS 06-0014 Secondary Substation Earthing Design EDS 06-0017 Customer Installation Earthing Design EAS 06-0011 Earthing Materials EDS 07-0105 Grid and Primary Standard Civil Designs EDS 07-0106 Substation Flood Protection EDS 08-0109 11/6.6kV Distribution Network Design EDS 08-0113 Guidance for the Application of ENA Engineering Recommendation G88 and G81 Inset Networks (IDNOs and other Licensed DNOs) EDS 08-0141 Customer HV Supplies EDS 08-0145 EHV Design EDS 08-0051 Customer Supplies between 6.6 & 33kV – Notes of Guidance for New Demand & Generation Connections EDS 08-0142 Planning Requirements for Secondary Substations External Documents ENA ER G81 Framework documents in 7 parts for competition in connection ENA E Rep2 Guidance on Security of Substations CDM 2007 The Construction (Design and Management) Regulations 2007 © UK Power Networks 2015 All rights reserved 11 of 11
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