Transmission Substation Field Instructions

Transcription

1 4.14 Substatin Permits Purpse This instructin deals with the use f permits t wrk in Hrizn Pwer s, and must be read in cnjunctin with FI 4.4 Secndary Islatins. Scpe The persnnel cvered by this instructin are, peratinal persnnel, nn-peratinal persnnel, visitrs and including Wrkers perating, servicing, and/ r maintaining (MPS) Micr Pwer Systems electrical equipment. This instructin cvers the permits and perating agreements (OA) t wrk n Hrizn Pwer transmissin substatins, transmissin lines and pilt cables. This als cvers wrk related t Independent Pwer Prviders (IPP) and imprtant cnsumers at 66 kv and abve. Permits are applied n bth primary plant and secndary plant and t trained and authrised persnnel. Safety Befre cmmencement f wrk, a risk assessment must be carried ut using the Risk Analysis Prcedure (OSH ), t identify and dcument the hazards and risks assciated with the task and ensure apprpriate cntrl measures are implemented. It is imprtant that, apprpriate cntrl measures must be identified, dcumented and implemented in rder t cntrl hazards t As Lw as Reasnable Practicable (ALARP). Systems There are primary and secndary systems that make up the Hrizn Pwer transmissin netwrk. Wrking n each f these systems requires a separate permit. Primary Systems Primary systems incrprate all plant and equipment that can be cnnected t high vltage (HV) levels f a substatin. The key pieces f primary systems are: Circuit breaker Vltage transfrmer Current transfrmer Islatr r discnnectr Earth switch Surge diverter Pwer transfrmer Transmissin line Capacitr CS# FI 4.14 Substatin Permits Page 1 f 8

2 Reactr Primary plant als includes any equipment directly assciated with the HV plant, such as: Buchhlz relays n transfrmers SF6 gas pressure switches n circuit breakers Secndary Systems Secndary systems incrprate all plant and equipment that cannt be cnnected t HV levels f a substatin. This field instructin nly related t the secndary systems this includes: Pilt systems Prtectin circuits Metering circuits Auxiliary systems Tele Prtectin Signalling (TPS) cmmunicatins The fllwing secndary systems are nt relevant t this field instructin: Cmmunicatins Building AC Distributin Bard SCADA DC chargers/batteries Fire alarm systems secndary plant in pwer statins, including generatr step-up transfrmers gas turbine sites, including generatr step-up transfrmers distributin circuits utside the zne substatin bundary reginal pwer statin sites distributin line and cable apparatus Permit Issuers and Recipients There are certain requirements that a persn must meet in rder t receive a permit and, nce granted, the permit recipient als has specific respnsibilities. This sectin als describes sme f the respnsibilities f the persn issuing the permit, wh is knwn as the Issuing Officer (IO). CS# FI 4.14 Substatin Permits Page 2 f 8

3 Permit Recipients Primary and Secndary Systems In rder t wrk n primary and secndary systems, a persn must have received a permit frm an IO. Depending n the situatin and type f permit, a persn wh has received a permit is knwn as a: Recipient in Charge (RIC) Tester in Charge (TIC) Recipient / Tester T be eligible t receive a permit, a persn must be apprpriately trained, familiar with Hrizn Pwer prcedures. Permit Recipients Secndary Systems Only In additin t the requirements listed abve, a persn must als have the fllwing in rder t wrk n secndary systems: Meet the requirements fr wrking n primary systems. Be cmpetent in Secndary Systems. If required t receive r issue a Secndary System Permit n equipment that has a nrmal wrking vltage that exceeds 50 V AC r 120 V DC, hld a current and valid Electrical Wrker s Licence r Line wrker Cert. III qualificatin (r equivalent). Nte: A permit is nt required t wrk n systems that perate at extra lw vltage (LV) (0-50 V AC r V DC) althugh it is still a requirements t islate the take ther precautins (always treat as live). Systems perating at LV and abve DO REQUIRE a permit fr access. Permit Recipient Respnsibilities It is highly recmmended that the rle f the IO and the RIC r TIC is perfrmed by different individuals. In circumstances that prevent this, extra care must be taken t ensure that islatin and checking are rigrusly dne. The permit recipient must be certified fr receiving permits n pilt cables fr the purpses f testing. The RIC and TIC have the respnsibility t ensure that each member f their wrking team fully understands the bundaries f the wrk area, cnditins f access and the duty f care required. It is als their respnsibility t ensure that the persnnel under their cntrl are adequately trained and cmpetent fr the required wrk. All recipients are t clearly understand that they have a respnsibility with regard t duty f care. CS# FI 4.14 Substatin Permits Page 3 f 8

4 Issuing Officer (IO) Respnsibilities Lgging f Secndary Systems Permits When a secndary system permit is issued, the IO must lg the permit with the apprpriate cntrl centre befre the wrk begins. This is necessary s that: The cntrl centre knws that peple are wrking n a particular item f secndary equipment and are aware f any implicatins t the pwer system, such as the risk f unwanted tripping. The cntrl centre can alert the IO if anther persn attempts t issue a permit n the same r assciated equipment. This is particularly imprtant with permits n pilt cables where it is pssible that smene may access a pilt junctin bx at the same time as HV testing is being carried ut. Cancellatin f Secndary Systems Permits Upn cmpletin f the wrk fr which the permit was issued, the secndary systems IO must: 1. Ensure that: All recipients have signed ff the permit and acknwledged that they will n lnger have access t the equipment. The RIC / TIC have relinquished the permit. The equipment is in the required cnditin fr the next stage f the wrk. 2. Restre all islatins back t a nrmal state r set up fr the next stage f the wrk. 3. Cancel the permit and advise the respective cntrl centre that the permit has been cancelled. If applicable, the cnditin f the equipment is t be nted n the subsequent STT permit (sme, part r all secndary circuits might be re-energised). The Secndary Islatin Schedule (SIS) must als be updated t reflect the revised status f the secndary islatins and attached t the STT. Wrk Permit Types There are a variety f permits that cver wrk in transmissin substatins, issued accrding t the situatin. Vicinity Authrity (VA) A VA is issued by Hrizn Pwer and authrises wrk near live electrical apparatus by authrised persns where there is a pssibility f encrachment int the minimal apprach distance (MAD), such as: Primary systems vegetatin management wrk near transmissin lines and substatins Secndary systems wrk near (but n access required t) secndary systems. CS# FI 4.14 Substatin Permits Page 4 f 8

5 Electrical Access Permit (EAP) An EAP is issued by Hrizn Pwer and authrises access t, and wrk n, an electrical apparatus that has been made safe thrugh islating and earthing (HV) r shrt-circuiting (LV), such as: Primary systems wrk n plant such as lines, cables and transfrmers Secndary systems: wrk n prtectin, cntrl and metering circuits EAP fr primary plant plus a Secndary Islatin Schedule (SIS) EAP fr secndary systems, with Sectin 3 n the EAP endrsed by Secndary Islatin Only as n prtective earthing is applied t secndary systems. Nte: When access t secndary plant is authrised by a primary plant EAP, the islated secndary plant might nt be earthed. This may be because it is extra LV and s des nt need t be earthed, r it is t remain live fr peratinal maintenance purpses. Bth f these need suitable islatins t primary plant. If a primary plant permit requires secndary islatins, the primary plant permit IO has t state the islatins in the respective sectin f the permit fr the secndary islatin fficer. Access t secndary plant is permitted after the required secndary plant islatins have been cmpleted by the secndary islatins fficer, and the RIC has been instructed n the cnditins f the access. These cnditins must be attached t the Secndary Islatins Schedule (SIS) f the EAP. In the case f a Secndary EAP, the IO will write Islatins per attached SIS and give instructin accrding t the cnditins f access. Sanctin t Test (STT) A STT is issued by Hrizn Pwer and authrises access t Hrizn Pwer s netwrk fr the purpse f testing, cmmissining and energising its electrical apparatus, such as: Primary systems example/s Secndary systems - wrk n nn-islated, peratinal r secndary circuits, testing f primary circuits and remval f prgram earths fr testing purpses. An SIS may be required. CS# FI 4.14 Substatin Permits Page 5 f 8

6 Nte: An EAP and a STT must nt be simultaneusly issued n the same side f the equipment, n either the primary r secndary side f plant. Hwever, when wrking n ppsite sides f plant, an EAP must be issued fr primary plant and an STT fr secndary plant. In this case bth the EAP and the STT are bund by an OA. The OA details must be recrded n bth permits. In the case f remedial repair r cnstructin wrk n an item f primary plant which nly requires an STT, all wrkers must wrk under the safety instructins f the STT and the cntrl f the TIC. Tele Prtectin Signalling (TPS) Equipment An STT issued t cmmunicatins staff t wrk n TPS equipment must: Be accmpanied by a Secndary Islatin Schedule (SIS). Fr mre n this, see Use f Secndary Islatin Schedule (SIS) with Permits in this field instructin. Be issued t the TIC in persn, i.e. it must nt t be issued remtely. Operating Authrities Operating Authrities have clearly defined areas f respnsibility within Hrizn Pwer s netwrk fr apprving and timing utages. Hrizn Pwer Cntrl Centre (HPCC) HPCC cntrls the transmissin system frm HV terminals f the generatr step-up transfrmers t zne and terminal substatins. This excludes distributin-side feeder s circuit breakers n indr and utdr switchgear. HPCC is als respnsible fr: Organising HV utages t private custmers and private pwer generatr (PPG s.) Managing primary wrk permits within its Operating Authrity bundaries. Nte: Permits t Wrk in transmissin substatins must be lgged by HPCC. Apprving and timing utages frm zne substatins t the distributin netwrk. It als manages utages affecting private custmers and PPGs cnnected t the Hrizn Pwer Distributin Netwrk. CS# FI 4.14 Substatin Permits Page 6 f 8

7 Pwer Statin Authrities IPP and ther privately run pwer statins, in cnsultatin with System Management, are respnsible fr apprving and timing utages in their pwer statins. Their authrity is frm the generatr t the HV terminals f step-up transfrmers and including any assciated LV systems. Operating Agreement (OA) An OA is nt a permit. Rather, it is an agreement between tw perating authrities and used t cnfirm that the state f an peratinal electrical apparatus will be held in an agreed state until the OA is cancelled. An OA is applied: t equipment wned by Hrizn Pwer and anther cmpany When a custmer plant requires maintenance, cnstructin upgrade and/r tests, they request t islate their plant frm HP netwrk and vice versa t re-cnnect it. These tw islatin scenaris are made by an OA in each case n Hrizn Pwer netwrk When maintenance is required n ne f tw parallel transmissin lines installed n the same structures, an OA is required fr wrk befre and during line maintenance until it is restred back t nrmal cnditins. t pilt cable schemes in the Hrizn Pwer netwrk Example When wrk must be dne n a pilt cable that requires ther apparatus n the netwrk t be de-energised, an OA is required fr wrk befre and during the wrk until the ther apparatus is restred back t nrmal cnditins. The fllwing is an example f hw an OA is rganised fr wrk n a pilt cable scheme. It is mandatry fr safety reasns t switch ff the pwer lines abve them n the same structure. This is t avid induced vltage in the pilt cable by thse pwer lines abve. This is started by sending a Ntice f Intentin t Wrk (NOIW) t HPCC fr scheduling the respective islatin switching prgram fr the transmissin line. FPS then requests HPCC t islate the transmissin line. The OA must clearly indicate the line s pick ID f the equipment and its islatin pints which must be lcked ff, tagged ff and acknwledged by FPS. The OA number must be referenced n the Secndary System permit. In this case, Secndary Systems use an EAP r a VA permit f their wn t wrk n the pilt cable. Permits t Access Assets Nt Owned by Hrizn Pwer T wrk n assets that are nt wned by Hrizn Pwer, the permit is issued by the bdy respnsible fr the asset. Nte: Fr wrk n nn-hrizn Pwer assets, see FI 5.1 Cnsumer Site Access, in this manual. CS# FI 4.14 Substatin Permits Page 7 f 8

8 Use f Secndary Islatin Schedule (SIS) with permits When a single apparatus is split int tw separate apparatus by electrical islatin, an STT can then be issued n the assciated secndary equipment while an EAP is in frce n the primary equipment. This can nly be dne if an SIS is made fr the wrk and attached t bth relevant permits. Bth persns in charge must: Agree with applying the primary and secndary islatins. Maintain strict cntrl and management f their wrksite. Effectively cmmunicate t ensure that neither team can impact upn the ther during the curse f their activities. A typical situatin is when the prtectin scheme fr a line breaker is islated frm the assciated line circuit breaker mechanism. If primary and secndary wrk teams are in agreement t test the line prtectin schemes under a secndary system STT while the primary side f the breaker is being maintained under an EAP, Primary and secndary systems must be bund by an OA. References Occupatinal Safety & Heath Act 1984 Occupatinal Safety & Health Regulatins 1996 SHMS OSH Jb Risk Analysis (JRA) Prcedure SHMS OSH Persnal Prtective Equipment Electrical Safety Standards Field Instructin 1.3 Cnstructin Site Access-Minimum Requirements Field Instructin 2.6 Wrksite Clthing / Persnal Prtectin Equipment Requirements Field Instructin 2.17 Safe Apprach Distances Field Instructin 2.23 Jb Hazard and Risk Management (JRA) 4.1 Substatin Entry Requirements Field Instructin 4.4 Secndary Islatins Field Instructin 4.14 Substatin Permits Field Instructin 8.21 Wrk Permits CS# FI 4.14 Substatin Permits Page 8 f 8