Northern Powergrid Appendices A and B for ENA Engineering Recommendation G81 Part 1: Design and Planning

Transcription

1 Versin:- 2.0 Date f Issue:- Sept 2013 Page 1 f 9 Nrthern Pwergrid Appendices A and B fr ENA Engineering Recmmendatin G81 Part 1: Design and Planning Framewrk fr design and planning, materials specificatin, installatin and recrd fr lw vltage husing develpment installatins and assciated new HV/LV distributin substatins 1. Purpse This dcument frms Appendix A and B t Energy Netwrks Assciatin (ENA) Engineering Recmmendatin (ER) G81 Part 1: Design and Planning, Framewrk fr design and planning, materials specificatin, installatin and recrd fr lw vltage husing develpment installatins and assciated new HV/LV distributin substatins and shuld be read in cnjunctin with that dcument. This dcument cntains a summary f the infrmatin cntained in Nrthern Pwergrid netwrk design plicies. Please nte that Nrthern Pwergrid is unable t prvide cpies f external dcumentatin, standards and specificatins referenced in this dcument, but cpies may be btained frm the relevant issuing bdy (such as the British Standards Institutin (BSI) r Energy Netwrks Assciatin). If additinal details are required, reference shuld be made t the individual plicy dcuments cited in sectin 7. This dcument supersedes the fllwing dcuments, all cpies f which shuld be destryed. Ref Versin Title G81 Part Engineering Recmmendatin G81 Part 1: Design and Planning 2. Scpe This dcument applies t the prviders f netwrk cnnectins t the distributin netwrk wned and perated by Nrthern Pwergrid (Nrtheast) Ltd and Nrthern Pwergrid (Yrkshire) plc Nrthern Pwergrid (Nrtheast) Ltd and Nrthern Pwergrid (Yrkshire) plc are the Distributin Netwrk Operatrs (DNOs) f Nrthern Pwergrid.

2 Versin:- 2.0 Date f Issue:- Sept 2013 Page 2 f Cntents 1. Purpse Scpe Cntents General Obligatins System Vltages Design Infrmatin Data Required frm Applicant Feeder Infrmatin Maximum Vltage Unbalance Custmer Demand Custmer Infrmatin Unmetered Supplies Data Specific t Hst DLH Substatin Lcatin and Netwrk Layut Cable Lcatin Transfrmers Maximum Vltage Drp frm LV Busbars f HV/LV Substatin Maximum Service Vlt Drp Maximum Vltage Unbalance Maximum Earth Lp Resistance Phase t Neutral Fault Clearance Time Prspective Shrt Circuit Current (PSCC) at LV busbars f HV/LV Substatin Prspective Shrt Circuit Current (PSCC) at the Cut Out Lss Evaluatin Criteria Emplyed: Ecnmic Ratings ADMD Infrmatin Maximum Number f Services per Jint Service Entry Requirement Earthing Undergrund Cable Ratings Criteria fr HV and LV Cables References Internal References... 9

3 Versin:- 2.0 Date f Issue:- Sept 2013 Page 3 f 9 3. General Obligatins The main bdy f Engineering Recmmendatin G81 Part 1 draws the applicants attentin t the wide range f bligatins t which system extensins must cnfrm. The applicants attentin is drawn in particular t: The bligatin under sectin 9 f the Electricity Act 1989 (as amended) t develp and maintain an efficient, c rdinated and ecnmical system f electricity distributin; and The bligatins under the Electricity Safety, Quality and Cntinuity Regulatins (ESQCR) 2002, Regulatin 3 that assets must: Individually be fit fr purpse; and Be arranged s as t prevent danger r interruptin f supply, s far as is reasnably practicable. 4. System Vltages Applicants shuld nte that the Nrthern Pwergrid (Nrtheast) Ltd system includes large sectins running at nn standard pressures, specifically a set f systems perating at nminal pressures within the kv range, and an extensive system perating at 20 kv. 5. Design Infrmatin Data Required frm Applicant 1 The design infrmatin listed in sectin 5 shuld be prvided by the applicant as part f the cnnectin design prcess Feeder Infrmatin Fr each feeder: Number f Custmers and cnnectins n each phase; Feeder rating and maximum feeder lad: Amps; Fuse selected and minimum fusing current (phase t earth fault at remte end): Amps; Maximum vltage regulatin at a cut ut psitin: +/ % n 230 V base; and Maximum earth lp resistance: milli hms Maximum Vltage Unbalance Maximum vltage unbalance at any pint: % Custmer Demand A listing f demand prfile classes and annual energy cnsumptin used fr each categry f service, tgether with the fllwing infrmatin (as required in Distributin Cde DPC 5.2.1): - Individual maximum pwer requirements: kva r kw; 1 Sectin 5 relates t ENA ER G81 Part 1: Appendix A

4 Versin:- 2.0 Date f Issue:- Sept 2013 Page 4 f 9 - Type and electrical lading f equipment t be cnnected, e.g. number and size f mtrs, ckers, shwers, space and water heating arrangements, including details f equipment which is subject t switching by the Supplier; and - Diversity: % f aggregate maximum pwer requirement Custmer Infrmatin Fr each Custmer s cnnectin: Maximum design Prspective Shrt Circuit Current (PSCC): ka; and Phase neutral lp impedance and, if different, phase earth lp impedance: milli hms Unmetered Supplies Classes and max demands as per Balancing and Settlement Cde Prcedure (BSCP) Data Specific t Hst DLH Substatin Lcatin and Netwrk Layut These requirements are intended t ensure that the design cmplies with the fllwing bligatins: Under sectin 9 f the Electricity Act 1989 (as amended) t develp and maintain an efficient, crdinated and ecnmical system f electricity distributin; Under the Health and Safety at Wrk Act 1974 and the Cnstructin (Design and Management) Regulatins 1994 t design safety int ur system frm the utset; and Under the Envirnmental Prtectin Act 1990 t avid statutry nuisance. All HV substatins shall be lped in t the apprpriate HV circuit. All substatin plant and cables shall be sized t take accunt f credible future develpments. All substatins shall be placed as near as practicable t the lad centre, taking accunt f credible future develpments; this will require a dialgue between Nrthern Pwergrid and the develper. Intercnnectin shall be prvided t supprt the LV netwrk f a substatin supplied frm an HV tee, r f existing substatins that require regular dead tank maintenance, if it can be achieved ecnmically frm a LV netwrk with an independent HV surce. Otherwise, intercnnectin shuld nly be prvided where it is pprtune s t d, specifically where: Less than 50 metres f additinal LV main is required; r The LV cable can be laid in a cmmn trench with the HV cable. Natural ventilatin shall be prvided in all parts f the substatin buildings cntaining transfrmers. Where practicable, the design f the substatin building shall prvide the capacity t vent the prducts f any explsin t atmsphere away (preferably upwards) frm the ptential lcatins that staff r members f the public may be in the event f unfreseen failure f equipment. 2 Sectin 6 relates t ENA ER G81 Part 1: Appendix B

5 Versin:- 2.0 Date f Issue:- Sept 2013 Page 5 f 9 All substatins shall be placed and r designed t mitigate the risk frm ptential fld damage. Where a new substatin is t be installed as part f a custmer s develpment and it is at risk f flding, the substatin shall be designed t be prtected against the ptential fld depth. The develper shall be respnsible fr carrying ut a fld risk assessment and it shuld be made available t the cmpany alng with the prpsed fld mitigatin measures fr the develpment. All csts assciated with cmpliance with this plicy shall be met by the develper. Further guidance n fld risk assessment and mitigatin measures can be fund in the Nrthern Pwergrid Cde f Practice (IMP/001/012 Cde f Practice fr Fld Mitigatin at peratinal premises) In general new substatins shall nt be lcated at the basement level f a prpsed develpment unless the develper prvides sufficient evidence that the ptential fld risk has been mitigated and the substatin des nt create a cnfined space. New distributin substatin buildings shall be designed t cnfrm t the current versin f The Building Regulatins and reflect any additinal lcal planning authrity requirements. S far is as reasnably practicable, the substatin building shall be f a visual cnstructin apprpriate t the surrunding develpment. Substatin buildings with flat rf cnstructins are prhibited. New distributin substatins frming part f a new husing develpment may be f prefabricated cnstructin in accrdance with the Nrthern Pwergrid specificatin (NPS/006/002 Technical Specificatin fr Prefabricated Distributin Substatin Enclsures) r a masnry cnstructin t match that develpment. In such cases, the materials will usually be prvided by the develper as part f the verall site develpment. The fundatin f the substatin shall be f a cncrete plinth r fundatin blck cnstructin with apprpriate prvisin fr cabling and ther services. The substatin drs shall be prvided with stays that enable the dr t be fixed in an pen psitin at 110 degrees t the substatin frnt face. The substatin shuld be designed s that, where pssible, the majrity f materials are maintenance free fr the nminal life f the substatin. All earthing and bnding at new distributin substatins shall be cmpliant with the Nrthern Pwergrid Cde f practice (IMP/010/011 Cdes f practice fr Earthing LV Netwrks and HV Distributin Substatins). The substatin building shall be free f any fthlds r climbing aids in rder t minimise the risk f unauthrised access t the substatin rf. All substatins shall be prvided with security measures apprpriate t the risk f unauthrised access, specifically: Fr sites that are classified as high r medium risk (in accrdance with the guidance ntes t the Electricity Safety, Quality and Cntinuity Regulatins 2002), the substatin shall be certified t Building Research Establishment Lss Preventin Standard LPS 1175 security rating classificatin 4. The standard f lcking arrangement shall prvide security against unauthrised access cmmensurate with that prvided by the enclsure; r The cnstructin f substatins at sites classified as lw r negligible risk (in accrdance with the guidance ntes t the Electricity Safety, Quality and Cntinuity Regulatins 2002) shall be certified t Building Research Establishment Lss Preventin Standard LPS 1175 security rating classificatin 2. The standard f lcking arrangement shall prvide security against unauthrised access cmmensurate with that prvided by the enclsure. Substatins that are detached frm any ther buildings are preferred. If an integral substatin cannt be avided, the fllwing precautins must be undertaken at the develper s expense: Fr the safety and cnvenience f staff accessing the substatin: Substatins shall be at grund level with direct 24 hur unrestricted access frm the public highway; and Substatins shall nt create a cnfined space and there must be free natural ventilatin f the site. T minimise statutry nuisance:

6 Versin:- 2.0 Date f Issue:- Sept 2013 Page 6 f 9 The substatin chamber shall be f dimensins that attenuate, rather than amplify, transfrmer nise; Lw nise transfrmers shall be used; The transfrmer shall be munted n anti vibratin pads s as t damp vibratin; Ventilatin shall be arranged s as t direct nise away frm custmers premises; A minimum f 3m shall be prvided between all cnductrs and any chamber likely t be used by the Custmer fr electrnic equipment; and All chambers immediately adjining the substatin chamber, including thse directly abve and belw shall nt be such that they will, r might credibly at sme time in the future, be used as dwellings. Fr example, in blcks f flats, nly cmmunal areas are permitted adjacent t the substatin chamber Cable Lcatin LV and HV cables shuld generally be installed in ftpaths. In ftpaths, LV cables shall be buried at a depth f 450mm and have a 150mm tile tape laid directly abve. HV cables shall be buried at a depth f 600mm and have a 200mm tile tape laid directly abve. Rad crssings shall be ducted, with spare ducts prvided, belw the rad cnstructin and in any case at a depth f nt less than 750mm. HV and LV cables shall be separated s far as is reasnably practicable, and in any case spaced at n less than 300mm between centres, t prevent danger and t facilitate future wrks. Cables shall be lcated in accrdance with Nrthern Pwergrid Netwrk Service Prcedure NSP/002 Plicy fr the Installatin f Distributin Pwer Cables Transfrmers Standard sizes in accrdance with materials specificatins, maximum 1000 kva (chice determined by assessed lad, including grwth rates fr current develpment and prvisin fr credible future develpment) shuld be used. Permissible cyclic ratings can be calculated in accrdance with BSI BS IEC :2005 (taking int accunt lad curves frecast by the applicant and the effects f enclsure). Transfrmers shall be in accrdance with Nrthern Pwergrid Netwrk Prduct Specificatin NPS/003/011 Technical Specificatin fr 11 and 20kV Distributin Transfrmers Maximum Vltage Drp frm LV Busbars f HV/LV Substatin T remte end f service: Urban netwrk 7% n 230V Rural netwrk 5% n 230V T end f main, where n service exists: Urban netwrk 6% n 230V Rural netwrk 4% n 230V Here rural netwrks are defined as thse mre than 15 km 3 frm the nearest primary substatin. The lcatin f primary substatins is given in the published Lng Term Develpment Statement (LTDS) Maximum Service Vlt Drp The maximum service vlt drp, between LV main and service cut ut is 1%.

7 Versin:- 2.0 Date f Issue:- Sept 2013 Page 7 f Maximum Vltage Unbalance Maximum vltage unbalance, at any pint shuld nt t exceed 10% Maximum Earth Lp Resistance T end f service 250 milli hms. T end f main, where n service exists, 200 milli hms. 3 30km where the HV netwrk perates at 20kV 6.8. Phase t Neutral Fault Clearance Time Nt mre than 60s fr a fault at the end f the service. Nt mre than 30s fr a fault at the end f the main, where n service exists Prspective Shrt Circuit Current (PSCC) at LV busbars f HV/LV Substatin Typical maximum 25 ka. All equipment t be capable f withstanding 36 ka Prspective Shrt Circuit Current (PSCC) at the Cut Out Design values t be established by applicant. All equipment t capable f withstanding 16 ka fr single phase cnnectins up t 100 A Lss Evaluatin Criteria Emplyed: Ecnmic Ratings Schemes shall be evaluated assuming a capitalised cst f lsses f 200 per MWh f average annual lsses. Fr example, a design that wuld incur 100 MWh per year f lsses (aggregate f fixed and variable) wuld have attributed t it a capitalised cst f lsses f 200 * 100 = 20, ADMD Infrmatin T be prvided by applicant. An allwance f 1% per annum fr each f twenty years frm cmmissining shall be made fr grwth f unrestricted r day units. Zer grwth allwance shall be made fr night (restricted hur) demand Maximum Number f Services per Jint Fur single phase service cables (making a cnnectin t nly tw f the three phases) t be terminated per cable jint; r Tw three phase service cables t be terminated per cable jint Service Entry Requirement Each prperty is t be prvided with an individual service via a duct (with draw wire) fr direct cnnectin t the LV main. Branched service arrangements will NOT be allwed.

8 Versin:- 2.0 Date f Issue:- Sept 2013 Page 8 f 9 On new husing develpments the preferred methd f service entry t a custmer s electrical installatin is via a 38mm service tube (hckey stick) up the external wall t an utdr meter cabinet, cmplying with Nrthern Pwergrid Specificatin (NPS/002/007 Technical Specificatin fr meter Bards and Outdr meter Cabinets). Where an internal psitin is agreed, the service terminatin MUST be munted n 12mm thick class O, nncmbustible, resin bnded particle bard f minimum density 600kg/m 3 and cnfrming t type P2 t P7 as detailed in BS EN 312. Service cables shall be at least 25 mm2 cncentric and at least 35 mm2 cncentric if in a duct in the internal cavity Service cables shall be terminated nt an insulated cut ut with cmbined neutral and earth terminals, rated at 100 Amps, which shall cmply with the requirements f BS 7657, and be equipped with 80 Amp fuses t BD HD , and BS Earthing All new netwrks and custmers cnnectins will be t Prtective Multiple Earth (PME) standards as laid ut in ER G12/3, save fr individual installatins where PME wuld be unsafe (e.g. filling statins). All earthing and bnding shall be cmpliant with the Nrthern Pwergrid Cde f practise (IMP/010/011 Cdes f practice fr Earthing LV Netwrks and HV Distributin Substatins). Custmer s main earthing lead minimum crss sectinal area: 16 mm2 cpper Undergrund Cable Ratings Criteria fr HV and LV Cables Cables as laid ut in the materials specificatin nly t be used, applying the fllwing factrs: Cntinuus ratings in accrdance with ENATS r manufacturers specificatins. Sil thermal resistivity g = 1.2 C metres per watt. Grund ambient temperatures 15 C. Maximum cnductr temperatures in accrdance with ENATS r manufacturers specificatins. Definitin f cyclic ratings in accrdance with IEC 853: grup de rating factrs in accrdance with ERA Ducts maximum lengths withut de rating 20m. Applying the lss evaluatin criteria laid ut abve means that the use f 185 mm 2 LV cable shall be restricted t industrial and cmmercial services nly. Netwrks shall be designed using 300 mm 2 cables ther than fr shrt tail end spurs carrying less than 120 A per phase (e.g. cul de sacs), where 95 mm 2 cable may be used.

9 Versin:- 2.0 Date f Issue:- Sept 2013 Page 9 f 9 7. References 7.1 Internal References Reference IMP/001/909 IMP/001/010 IMP/001/012 IMP/001/911 IMP/010/011 IMP/003/001 NPS/002/007 NPS/006/002 Title Cde f Practice fr Distributin System Parameters Cde f Practice fr Standard Arrangements fr Custmer Cnnectins Cde f Practice fr Fld Mitigatin at Operatinal Premises Cde f Practice fr the Ecnmic Develpment f Lw Vltage Netwrks Cde f Practice fr Earthing LV Netwrks and HV Distributin Substatins Cde f Practice fr the Cnstructin and Building Design f Grund Munted Secndary Substatins Technical Specificatin fr Meter Bards and Outdr Meter Cabinets Technical Specificatin fr Prefabricated Distributin Substatin Enclsures