Operating Process for Access to Gas Insulated Switchgear

Transcription

1 Operating Prcess fr Access t Gas Insulated Switchgear Summary This dcument supprts the Pwer System Safety Rules and its requirements assembled under Operate Gas Insulated Switchgear - Categry 5.6 Dcument Cntrl Revisin n: 2 HP TRIM N: Apprval/ Reviewed date: 28 August 2017 Business prcess: Manage Health, Safety & Envirnment Dcument type: Crprate-wide prcedure Prcess wner: Manager Health, Safety & Envirnment Authr: J Masn Reviewers: J Wrkman Apprver: K McCall, Manager Health, Safety & Envirnment Warning: A printed cpy f this dcument may nt be the current versin. Please refer t transgrid.cm.au t verify the current versin.

2 Table f Cntents 1. Overview Purpse Plicy Base Reference Dcuments Scpe Implementatin Dcument Lcatin Making GIS Equipment Safe fr Wrk Pwer System Safety Rules Requirements General Requirements Electrical and Mechanical Safety features Defeating f Interlcks during Operatinal Switching Defeating f Interlcks during Maintenance Activities Preparatin f Switching Instructins Order f Switching Operatins Making GIS Equipment Safe fr Wrk using Remte Operatin Islatin Earthing Securing the Islatin and Earthing Making GIS Equipment Safe t Wrk where Lcal peratin is required Islatin Earthing Definitins Change histry Mnitring and Review Appendix A: Equipment Features at TransGrid GIS Substatins Haymarket 132kV GIS Haymarket 330kV GIS Beacnsfield Suth and Beacnsfield Nrth 132kV GIS Hlryd 330kV GIS Rkwd Rd 330kV GIS Rkwd Rd 132kV GIS Taree GIS Orange GIS Sapphire GIS Appendix B: Example Switching Sequences Haymarket 132kV GIS - Feeder Bay Equipment Only (9SC feeder) Haymarket 132kV GIS - Feeder Only (9SC feeder) Haymarket 330kV GIS - Bay Equipment Only (CB 5412A) Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 2 f 19

3 1. Overview 1.1. Purpse This dcument prvides apprved prcedures fr Islating and Earthing High Vltage GIS Equipment in accrdance with the Pwer System Safety Rules Categry Plicy Base Dcument Pwer System Safety Rules 1.3. Reference Dcuments Dcument Access fr Wrk n High Vltage Apparatus 1.4. Scpe This dcument supprts the Pwer System Safety Rules and its requirements assembled under Operate Gas Insulated Switchgear - Categry 5.6 Accuntability Respnsible persn Manager/Health Safety and Envirnment Mgr Training Authrised persns Respnsibility Maintenance and wnership f this prcedure Implementatin f training prgrams assciated with this prcedure Cmply with this prcedure 1.5. Implementatin This prcedure is t be implemented in cnjunctin with the implementatin f TransGrid s Pwer System Safety Rules. It will be available as a resurce, published n the Wire. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 3 f 19

4 1.6. Dcument Lcatin Blck diagram shwing lcatin f dcument in relatin t thers. Pwer System Safety Rules Categry 5 Categry 6 Categry 7 Operating Prcess fr Access t HV Apparatus Operating Prcess fr Access t Gas Insulated Switchgear Access fr Wrk n HV Substatin Apparatus Access fr Wrk n HV Overhead Lines Access fr Wrk n HV Transmissin Cables Prcedures Safe Wrk Practices n HV Substatin Apparatus Safe Wrk Practices n HV Overhead Lines Safe Wrk Practices n HV Cables Wrk Instructins Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 4 f 19

5 2. Making GIS Equipment Safe fr Wrk 2.1. Pwer System Safety Rules Requirements The Pwer System Safety Rules require that: Making GIS Safe fr Wrk Fr nrmal switching peratins, GIS shall be perated remtely using the substatin Human machine Interface (HMI) r ther remte cntrl facility; and Manual peratin f GIS fr switching purpses shall nt be cnsidered when equipment is energised, as this will bypass all interlcking. Nrmally GIS switchgear must be perated remtely. Operatin frm the lcal cntrl cubicle is nt cnsidered t be remte peratin therefre if remte peratin is nt pssible then additin precautins are required as detailed in Sectin 2.4. In additin t these requirements, all wrkers shall vacate the GIS hall during switching peratins General Requirements Electrical and Mechanical Safety features Extensive interlcking is prvided at GIS substatins t inhibit the clsing f an earth nt live High Vltage cnductrs. Safety may als be prvided by three-psitin switches that are mechanically designed t prevent any individual phase frm being in mre than ne state at any ne time, i.e. a phase that switches t earth cannt physically als be in the clsed psitin at the same time. Characteristics f equipment specific t individual sites are prvided in Appendix A Defeating f Interlcks during Operatinal Switching Where the nature f the wrk requires the defeating f interlcks during peratinal switching Rules and f the Pwer System Safety Rules shall apply Defeating f Interlcks during Maintenance Activities After the issue f an Access Authrity it is permissible fr the wrk team t defeat interlcking n equipment under their cntrl during maintenance activities Preparatin f Switching Instructins The High Vltage Switching Instructin will nt be written in a manner that prescribes remte r lcal peratin fr each step. This will assist the wrk where remte peratin is unexpectedly unavailable. It will be the respnsibility f the authrised persn perfrming the switching t cmply with the requirements f sectin 2.3 and 2.4 f this prcedure. Example switching sequences that are written in this style are prvided in Appendix B Order f Switching Operatins All switching shall be carried ut in accrdance with all the nrmal rules and cnventins except: Earths may be applied prir t islating VT secndary circuits and will be the nrmal practice; Visual checking f individual switchgear status using the mechanical indicatin is nt required. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 5 f 19

6 Lcking and tagging f apparatus shall be undertaken when cnvenient, rather than immediately after cmpleting each individual peratin. This is t allw the switcher t cmplete a number f remte peratins befre returning t the switchgear. Nte: Fr certain types f switchgear it is necessary t lck the islatrs befre clsing the earths Making GIS Equipment Safe fr Wrk using Remte Operatin Where Remte peratin f GIS switchgear is available the requirements f this sectin apply. An example switching sequence that cmplies with this prcedure is prvided in Appendix B Islatin Islatin will be in accrdance with Rule 5.6.2(a) f the Safety Rules. The switchgear psitin n the HMI satisfies the requirements f this rule Earthing The applicatin f HV Access Authrity earths shall be in accrdance with Rule f the Pwer System Safety Rules. An apprved earthing methd shall be used that ensures: Earthing switches shall nly be clsed nt High Vltage cnductrs that are identified as deenergised frm all surces by vltage and/r discnnectr indicatin. Earthing switches may be applied t High Vltage cnductrs that are identified as de-energised if the earth is already in place and is being extended t ther cnductrs by the clsure f a circuit breaker Securing the Islatin and Earthing This is t be dne n the switchgear level by lcking / tagging effective pints f islatin in their pen psitins and lcking / tagging effective earthing switches in their clsed psitins 2.4. Making GIS Equipment Safe t Wrk where Lcal peratin is required When there is n capability t perate the GIS equipment remtely r the remte capability is nt functining then Rule f the Pwer System Safety Rules applies. The additinal safety precautins applicable in such circumstances are as fllws: Islatin The indicatin f the switchgear psitin must be established visually, either directly r by using apprpriate cameras. The gas pressure must als be cnfirmed as satisfactry Earthing There are n additinal requirements when earthing lcally. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 6 f 19

7 3. Definitins Nil 4. Change histry Revisin n Apprved by Amendment 0 EGM/Netwrk Services & Operatins 1 Ken McCall, Manager/Health Safety and Envirnment 2 Ken McCall, Manager/Health Safety and Envirnment Superseded dcument GD HS G3 001, Prcedure updated and restructured t include: - Beacnsfield Nrth and Beacnsfield Suth 132kV GIS (including renaming f the Prcedure) - Crrectin t EnergyAustralia references - References t current versin f the Pwer System Safety Rules Prcedure updated t include Hlryd and Rkwd Rd GIS Inclusin f sectin t cver defeating f interlcks during maintenance activities All significant new additins and alteratins t Revisin 1 have been highlighted in this versin by a red vertical sidebar. Editrial changes (where the intent has nt been changed) have nt been highlighted. The fllwinghas als been changed: - Scpe revised t be generic t GIS sites; - Duplicatin f PSSR requirements remved; - Sectin Sectin revised 5. Mnitring and Review The Manager/Health Safety and Envirnment is respnsible fr the nging mnitring and review f the dcuments assciated with the Pwer System Safety Rules. This can include but is nt limited t: (a) Requesting regular feedback n the effectiveness f prcedures and wrk instructins. Apprpriate feedback tls include fcus grups and nline assessments; (b) Where a change has ccurred in ur prcesses; and (c) Recmmendatins arising frm incidents. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 7 f 19

8 6. Appendix A: Equipment Features at TransGrid GIS Substatins 6.1. Haymarket 132kV GIS The 132kV GIS at Haymarket is ttally enclsed, three phase encapsulated SF 6 insulated with the fllwing features: All High Vltage switching peratins can be carried ut frm the substatin cntrl rm as well as frm the lcal cntrl panels n the equipment flr. It is nly necessary t g t the equipment flr fr switching purpses t carry ut lw vltage/mechanical islatins t render equipment inperable, t apply lcks and t apply tags. The discnnectr/earthing switches are three psitin switches. They are essentially a rtating switch that has the states clsed / pen / earthed, but they are plarised in that nly ne side f the switch can be earthed. The mechanical design f the switch prevents any phase being in the clsed and earthed psitin simultaneusly. A self-checking system is prvided n the three-psitin switches t mnitr drive mtr current; if the current is utside the nrmal perating range, the system renders the switch inperable and alarms the unhealthy cnditin. This is designed t detect mechanical prblems such as failure f the drive shaft between phases that culd result in (say) 2 phases being in the earthed psitin and 1 phase being in the clsed psitin. Fault-making high speed earthing switches n all cables (line side f line discnnectr nly) and n all transfrmers (transfrmer side f transfrmer discnnectr nly). Nn fault-making earthing switches in all 3-psitin switches and n all 132kV bus sectins. The electrical interlck system cnsists f hardwiring between auxiliary cntacts at the GIS and is separate frm the substatin cntrl system. A mal-peratin f the substatin cntrl system will nt affect the GIS interlcking system. The interlcking is functinal fr bth lcal and remte electrical peratin. Manual peratin f the devices ver-rides all interlcking. Manual peratin facilities are intended and designed fr maintenance purpses nly, after islatin and earthing has been cmpleted. Manual peratin facilities are neither intended nr designed t be used fr High Vltage switching purpses. The electrical interlck system incrprates the fllwing design philsphy: Earthing switch peratin is inhibited unless all f the assciated discnnectrs are pen Earthing switch peratin is inhibited when the equipment t be earthed is energised. Fr cables and bus sectins three phase VT secndary vltages are used fr this check. Discnnectr peratin is inhibited when the discnnectr is under lad, unless there are tw ther lcal parallel circuits clsed. Discnnectr peratin is inhibited frm applying an earth t an unearthed sectin f switchgear. Circuit breaker clse peratin is inhibited when assciated discnnectrs are in transit. The psitin f the equipment is determined by the use f auxiliary cntacts cnnected t the perating shaft. Mechanical status indicatin is available n the frnt panel f all device perating mechanisms. Due t the physical arrangement f the GIS this will nt be visible n all circuit breakers. Viewing f cntact psitin is prvided n all discnnectrs and earthing switches via windws fitted t the GIS chambers using fixed r prtable cameras depending n accessibility f the windw. The camera view can be difficult t interpret and the nging reliability f the cameras and ptical fibre cabling has nt been warranted by the manufacturer. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 8 f 19

9 Prving de-energised facilities have been prvided adjacent t all earthing switches using capacitive cupling t detect High Vltage. Due t the extremely limited accessibility f sme f these pints, caxial cables have been used t prvide access t them fr perating purpses. The nging reliability f the fixed caxial cables prvided fr prving de-energised equipment has nt been warranted by the manufacturer. Explsin venting has been designed such that the GIS may be perated safely frm the lcal cntrl panel Haymarket 330kV GIS Ttally enclsed Gas Insulated Switchgear (GIS) is used at Haymarket 330/132kV Substatin fr 330kV transfrmer bays and the 330kV cable 42 t Sydney Suth substatin. The 330kV GIS at Haymarket is ttally enclsed, single phase encapsulated SF 6 insulated with the fllwing features: All High Vltage switching peratins can be carried ut frm the substatin cntrl rm as well as frm the lcal cntrl panels n the equipment flr. It is nly necessary t g t the equipment flr fr switching purpses t carry ut lw vltage/mechanical islatins t render equipment inperable, t apply lcks and t apply tags. Discnnectrs and nn-fault making earthing switches have a single mtrised perating mechanism per three-phase set. High-speed fault making earthing switches have a single mtrised perating mechanism per phase and may be perated individually. A self-checking system is prvided n each discnnectr and earthing switch drive, t mnitr drive mtr current; if the current is utside the nrmal perating range, the system renders the switch inperable and alarms the unhealthy cnditin. This is designed t detect mechanical prblems such as failure f the drive shaft between phases that culd result in (say) 2 phases being in the pen psitin and 1 phase being in the clsed psitin. Fault-making high-speed earthing switches are directly cnnected t 42 cable and each transfrmer. All ther earthing switches are nt fault-making. The electrical interlcking system cnsists f hardwiring between auxiliary cntacts at the GIS and is separate frm the substatin cntrl system. A mal-peratin f the substatin cntrl system will nt affect the GIS interlcking system. The General De-Interlcking key switch at the lcal cntrl panel verrides all interlcking fr switchgear in that bay. Interlcking functins shall be active fr all High Vltage switching purpses. The electrical interlcking system is functinal fr bth lcal and remte electrical peratin. Manual peratin f the devices verrides all interlcking. Manual peratin facilities are intended and designed fr maintenance purpses nly, after islatin and earthing has been cmpleted. Manual peratin facilities are neither intended nr designed t be used fr High Vltage switching purpses. The electrical interlcking system incrprates the fllwing design philsphy: Earthing switch peratin is inhibited unless all f the assciated discnnectrs are pen, including n the 132kV side f the transfrmer fr transfrmer earthing switches. Discnnectr peratin is inhibited when the assciated circuit breaker is clsed. Discnnectr peratin is inhibited frm extending an earth t an unearthed sectin f switchgear. Circuit breaker clse peratin is inhibited when assciated discnnectrs are in transit. The psitin f the equipment is determined by the use f auxiliary cntacts driven by the perating shaft. Mechanical status indicatin is available at each phase f all equipment and is readily visible. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 9 f 19

10 Viewing f cntact psitin is prvided n all discnnectrs and earthing switches via windws fitted t the GIS chambers using prtable cameras. Viewing f the cntacts using the naked eye is nt recmmended due t the prximity t sme windws f mving, external linkages f the perating mechanism. There is n prvisin fr prving de-energised n the 330kV GIS. The lcal cntrl panels are lcated several metres frm the switchgear. Explsin venting has been designed such that the GIS may be perated safely frm the lcal cntrl panel Beacnsfield Suth and Beacnsfield Nrth 132kV GIS The 132kV GIS at Beacnsfield Suth and Beacnsfield Nrth substatins is ttally enclsed, three phase encapsulated SF 6 insulated with the fllwing features: All High Vltage switching peratins can be carried ut frm the substatin cntrl rm as well as frm the lcal cntrl panels n the equipment flr. It is nly necessary t g t the equipment flr fr switching purpses t carry ut lw vltage/mechanical islatins t render equipment inperable, t apply lcks and t apply tags. The discnnectr/earthing switches are three psitin switches. They cnsist f a single plunger that can nly mve lengthwise ne directin mving it twards the earthing psitin, the ther directin mving it twards the islatr clsed psitin. The mechanical design f the switch prevents any phase being in the clsed and earthed psitin simultaneusly. A mal-peratin n the three-psitin switches is indicated n the cntrl system by being in the Intermediate psitin. The interlcking system ensures that further peratin f this equipment is nt pssible if it is in the intermediate psitin. This status indicatr is available n the substatin cntrl system. Fault-making high speed earthing switches are n: all cables (line side f line discnnectr nly) all transfrmers (transfrmer side f transfrmer discnnectr nly). All bus sectin cnnectins (bus side f islatrs nly) Nn fault-making earthing switches in all 3-psitin switches and n all 132kV bus sectins. The electrical interlck system cnsists f hardwiring between auxiliary cntacts at the GIS and is separate frm the substatin cntrl system. A mal-peratin f the substatin cntrl system will nt affect the GIS interlcking system. The psitin f the equipment is determined by the use f auxiliary cntacts cnnected t the perating shaft. The interlcking is functinal fr bth lcal and remte electrical peratin. Manual peratin f the devices ver-rides all interlcking, blcking peratin f all equipment that is dependent n its state. Manual peratin facilities are intended and designed fr maintenance purpses nly after islatin and earthing has been cmpleted. Manual peratin facilities are neither intended nr designed t be used fr High Vltage switching purpses. The electrical interlck system incrprates the fllwing design philsphy: (a) Fr Line/Cable bays: Earthing switch peratin is inhibited unless all f the assciated discnnectrs are pen Line Earthing switch peratin is inhibited when the equipment t be earthed is energised. Three phase VT secndary vltages are used fr this check. Bus earthing switch peratin is inhibited unless all surces f supply are islated Circuit breaker clse peratin is inhibited when assciated discnnectrs are in transit r in an intermediate state Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 10 f 19

11 Cable bay Islatrs are inhibited frm peratin unless all bay Earth Switches are pen (b) Fr Bus Cuplers and bus sectin cnnectrs : Earthing switch peratin is inhibited unless all f the assciated discnnectrs are pen Circuit breaker clse peratin is inhibited when assciated discnnectrs are in transit r in an intermediate state. Cable bay Islatrs are inhibited frm peratin unless bth cupler Earth Switches are pen. Mechanical status indicatin is available n the Lcal Cntrl Cubicle. The status f all HV equipment that can be perated and the HV equipment n which its peratin depends (accrding t the interlcks) is available frm the Substatin Cntrl System. Viewing f cntact psitin is prvided n all discnnectrs and earthing switches via windws fitted t the GIS chambers using prtable cameras and light surces. Specific Prving de-energised facilities have nt been prvided. The nly indicatrs are: Visual indicatin via the windws; Electrical indicatin at the substatin level (N Vlts/N Current); and Use f VT Secndaries and/r HVDS system where fitted. Explsin venting has been designed such that the GIS may be perated safely frm the lcal cntrl panel Hlryd 330kV GIS Ttally enclsed Gas Insulated Switchgear (GIS) is used at Hlryd 330/132kV Substatin fr 330kV transfrmer bays, the 330kV lines 1C and 1F t Sydney West substatin and the 330kV Cables 43 and 44 t Rkwd Rd. The 330kV GIS at Hlryd is ttally enclsed, single phase encapsulated SF 6 insulated with the fllwing features: All High Vltage switching peratins can be carried ut frm the substatin cntrl rm as well as frm the lcal cntrl panels n the equipment flr. It is nly necessary t g t the equipment flr fr switching purpses t carry ut lw vltage/mechanical islatins t render equipment inperable, t apply lcks and t apply tags. Discnnectrs and nn-fault making earthing switches have a single mtrised perating mechanism per three-phase set. High speed fault making earthing switches have a single mtrised perating mechanism per three phase set. A self-checking system is prvided n each discnnectr and earthing switch drive, t mnitr drive mtr current; if the current is utside the nrmal perating range, the system renders the switch inperable and alarms the unhealthy cnditin. This is designed t detect mechanical prblems such as failure f the drive shaft between phases that culd result in (say) 2 phases being in the pen psitin and 1 phase being in the clsed psitin. Fault-making high-speed earthing switches are directly cnnected t: N.1 and N.2 330/132kV transfrmers (ESw 5410, 5420) 1F and 1C 330kV lines (ESw 1C0, 1F0) 43 and kV cables (ESw 430, 440) N.1 Capacitr (ESw 5710) 5X1 Spare Bay (ESw 5X10) Bus Sectins Earthing Switches 5110, 5120, 5130, All ther earthing switches are nt fault-making. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 11 f 19

12 The electrical interlcking system cnsists f hardwiring between auxiliary cntacts at the GIS and is separate frm the substatin cntrl system. A mal-peratin f the substatin cntrl system will nt affect the GIS interlcking system. The General De-Interlcking key switch at the lcal cntrl panel verrides all interlcking fr switchgear in that bay. Interlcking functins shall be active fr all High Vltage switching purpses. The electrical interlcking system is functinal fr bth lcal and remte electrical peratin. Manual peratin f the devices verrides all interlcking. Manual peratin facilities are intended and designed fr maintenance purpses nly, after islatin and earthing has been cmpleted. Manual peratin facilities are neither intended nr designed t be used fr High Vltage switching purpses. The electrical interlcking system incrprates the fllwing design philsphy: Earthing switch peratin is inhibited unless all f the assciated GIS discnnectrs are pen. This des nt include the 132kV side f the transfrmer fr transfrmer earthing switches. Discnnectr peratin is inhibited when the assciated circuit breaker is clsed. Circuit breaker clse peratin is inhibited when assciated discnnectrs are in transit. The psitin f the equipment is determined by the use f auxiliary cntacts driven by the perating shaft. Mechanical status indicatin is available n a single phase nly per three phase set and is readily visible. Viewing f cntact psitin is prvided n all discnnectrs and earthing switches via windws fitted t the GIS chambers where accessible. Viewing f the cntacts using the naked eye is nt recmmended due t the prximity t sme windws f mving, external linkages f the perating mechanism. There is n prvisin fr prving de-energised n the 330kV GIS. The lcal cntrl panels are lcated a few metres frm the switchgear. Explsin venting has been designed such that the GIS may be perated safely frm the lcal cntrl panel. Lcal lcking and tagging f a discnnectr is required after pening f a discnnectr and prir t clsing an adjacent earthing switch Rkwd Rd 330kV GIS Ttally enclsed Gas Insulated Switchgear (GIS) is used at Rkwd Rd 330/132kV Substatin fr 330kV transfrmer bays, the 330kV cables 43 and 44 t Hlryd substatin, and N. 4 Reactr Bay. The 330kV GIS at Rkwd Rd is ttally enclsed, single phase encapsulated SF 6 insulated with the fllwing features: All High Vltage switching peratins can be carried ut frm the substatin cntrl rm as well as frm the lcal cntrl panels n the equipment flr. It is nly necessary t g t the equipment flr fr switching purpses t carry ut lw vltage/mechanical islatins t render equipment inperable, t apply lcks and t apply tags. Discnnectrs and nn-fault making earthing switches have a single mtrised perating mechanism per three-phase set. High speed fault making earthing switches have a single mtrised perating mechanism per three phase set. A self-checking system is prvided n each discnnectr and earthing switch drive, t mnitr drive mtr current; if the current is utside the nrmal perating range, the system renders the switch inperable and alarms the unhealthy cnditin. This is designed t detect mechanical prblems such as failure f the drive shaft between phases that culd result in (say) 2 phases being in the pen psitin and 1 phase being in the clsed psitin. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 12 f 19

13 Fault-making high-speed earthing switches are directly cnnected t: N.1, N.2 and N.3 330/132kV transfrmers (ESw 5410, 5420, 5430) 43 and kV cables (ESw 430, 440) N.4 Reactr (ESw 5940/1) Bus Sectins Earthing Switches 5110, 5110/1, 5130, 5130/1. All ther earthing switches are nt fault-making. The electrical interlcking system cnsists f hardwiring between auxiliary cntacts at the GIS and is separate frm the substatin cntrl system. A mal-peratin f the substatin cntrl system will nt affect the GIS interlcking system. The General De-Interlcking key switch at the lcal cntrl panel verrides all interlcking fr switchgear in that bay. Interlcking functins shall be active fr all High Vltage switching purpses. The electrical interlcking system is functinal fr bth lcal and remte electrical peratin. Manual peratin f the devices verrides all interlcking. Manual peratin facilities are intended and designed fr maintenance purpses nly, after islatin and earthing has been cmpleted. Manual peratin facilities are neither intended nr designed t be used fr High Vltage switching purpses. The electrical interlcking system incrprates the fllwing design philsphy: Earthing switch peratin is inhibited unless all f the assciated GIS discnnectrs are pen. This des nt include the 132kV side f the transfrmer fr transfrmer earthing switches. Discnnectr peratin is inhibited when the assciated circuit breaker is clsed. Circuit breaker clse peratin is inhibited when assciated discnnectrs are in transit. The psitin f the equipment is determined by the use f auxiliary cntacts driven by the perating shaft. Mechanical status indicatin is available n a single phase nly per three phase set and is readily visible. Viewing f cntact psitin is prvided n all discnnectrs and earthing switches via windws fitted t the GIS chambers where accessible. Viewing f the cntacts using the naked eye is nt recmmended due t the prximity t sme windws f mving, external linkages f the perating mechanism. There is n prvisin fr prving de-energised n the 330kV GIS. The lcal cntrl panels are lcated a few metres frm the switchgear. Explsin venting has been designed such that the GIS may be perated safely frm the lcal cntrl panel. Lcal lcking and tagging f a discnnectr is required after pening f a discnnectr and prir t clsing an adjacent earthing switch Rkwd Rd 132kV GIS The 132kV GIS at Rkwd Rd substatin is ttally enclsed, three phase encapsulated SF 6 insulated with the fllwing features: All High Vltage switching peratins can be carried ut frm the substatin cntrl rm as well as frm the lcal cntrl panels n the equipment flr. It is nly necessary t g t the equipment flr fr switching purpses t carry ut lw vltage/mechanical islatins t render equipment inperable, t apply lcks and t apply tags. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 13 f 19

14 The discnnectr/earthing switches are three psitin switches. They cnsist f a single plunger that can nly mve lengthwise ne directin mving it twards the earthing psitin, the ther directin mving it twards the islatr clsed psitin. The mechanical design f the switch prevents any phase being in the clsed and earthed psitin simultaneusly. A mal-peratin n the three-psitin switches is indicated n the cntrl system by being in the Intermediate psitin. The interlcking system ensures that further peratin f this equipment is nt pssible if it is in the intermediate psitin. This status indicatr is available n the substatin cntrl system. Fault-making high speed earthing switches are n: all lines, cables and reactr bays (line side f line discnnectr nly) all transfrmers (transfrmer side f transfrmer discnnectr nly). All bus sectin cnnectins (ESw 4110, 4110/2, 4120, 4120/2, 4130, 4130/2). They are nt 3 psitin switches. All ther Earthing Switches are nt fault-making earthing switches. The electrical interlck system cnsists f hardwiring between auxiliary cntacts at the GIS and is separate frm the substatin cntrl system. A mal-peratin f the substatin cntrl system will nt affect the GIS interlcking system. The psitin f the equipment is determined by the use f auxiliary cntacts cnnected t the perating shaft. The interlcking is functinal fr bth lcal and remte electrical peratin. Manual peratin f the devices ver-rides all interlcking, blcking peratin f all equipment that is dependent n its state. Manual peratin facilities are intended and designed fr maintenance purpses nly after islatin and earthing has been cmpleted. Manual peratin facilities are neither intended nr designed t be used fr High Vltage switching purpses. The Interlcking system prevents the simultaneus peratin f apparatus, and will blck the peratin f ther HV equipment if the status f any mnitred HV equipment is in an intermediate psitin. The electrical interlck system incrprates the fllwing design philsphy: (a) (b) (c) Fr Transfrmer bays: Transfrmer Earthing switch peratin is inhibited when the transfrmer is nt islated n the 132kV and 330kV side. Fr Line bays: Earthing switch peratin is inhibited unless all f the adjacent discnnectrs are pen Bus earthing switch peratin is inhibited unless all surces f supply are islated Circuit breaker clse peratin is inhibited when assciated discnnectrs are in transit r in an intermediate state Fr Bus Cuplers: Earthing switch peratin is inhibited unless all f the assciated discnnectrs are pen Circuit breaker clse peratin is inhibited when assciated discnnectrs are in transit r in an intermediate state. Line bay Islatrs are inhibited frm peratin unless bth cupler Earth Switches are pen. Mechanical status indicatin is available n all CB s, Discnnectrs and earthing switches. The status f all HV equipment that can be perated and the HV equipment n which its peratin depends (accrding t the interlcks) is available frm the Substatin Cntrl System. Viewing f cntact psitin is prvided n all discnnectrs and earthing switches via windws fitted t the GIS chambers using prtable cameras and light surces. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 14 f 19

15 Specific Prving de-energised facilities have nt been prvided. The nly indicatrs are: Visual indicatin via the windws; Electrical indicatin at the substatin level (N Vlts/N Current); and Use f VT Secndaries and/r HVDS system where fitted. Explsin venting has been designed such that the GIS may be perated safely frm the lcal cntrl panel Taree GIS TBA 6.8. Orange GIS TBA 6.9. Sapphire GIS TBA Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 15 f 19

16 6.10. Appendix B: Example Switching Sequences Haymarket 132kV GIS - Feeder Bay Equipment Only (9SC feeder) Refer t Haymarket HVOD diagram HYM The fllwing switching sequence is an example that applies the principles fr islatin and earthing when using remte r lcal peratin f switchgear. Manual peratin is prhibited. It is assumed that the feeder and bth bus sectins will remain energised during an utage f the bay equipment. Nte that there are n integral earthing and shrt-circuiting equipment with adequate fault making capacity within the area t be islated s the requirements f Sectins and apply. All lcal and remte peratins are cmmn except thse specifically stated as Lcal Operatin r Remte Operatin. Switching t Islate and Earth Operative step Operating functin Secndary actin and explanatin OFF-LOAD 9SC Open CB 9SC2 Use CB status indicatin ISOLATE AND EARTH Open Disc 9SC5 Lcal Operatin : Ensure visible break exists Remte Operatin : Use discnnectr status indicatin t check change f status Open Disc 9SC6 Lcal Operatin : Ensure visible break exists Remte Operatin : Use discnnectr status indicatin t check change f status Open Disc 9SC1 Lcal Operatin : Ensure visible break exists Remte Operatin : Use discnnectr status indicatin t check change f status Check pen CB 9SC2 Use CB status indicatin Clse E/S 9SC0/2 (Nte 1) Use earthing switch status indicatin t check change f status Clse CB 9SC2 (Nte 2) Use CB status indicatin t check change f status Clse E/S 9SC0/A3 (Nte 3) Use earthing switch status indicatin t check change f status Clse E/S 9SC0/B3 (Nte 3) Use earthing switch status indicatin t check change f status Nrmal cnditin n cmpletin f PRI All three islatin pints are nw cnsidered cnfirmed and earths have been applied Ntes: (a) Earthing switch 9SC0/2 may be clsed because the HV cnductrs are indicated as de- energised frm the: busbars by bus discnnectr indicatin (r visible break if perating lcally), and cable by cable discnnectr indicatin (r visible break if perating lcally). Fllwing clsure f this earthing switch, earths are cnsidered t have been applied t the cnductrs between the line discnnectr and the circuit breaker. If the line discnnectr had nt pened successfully the interlcking wuld have prevented the earths frm being applied. The mechanical design f the 3-psitin switch prevents any ne phase frm being in the clsed and earthed psitins simultaneusly. (b) Clsing circuit breaker 9SC2 extends the earths frm E/S 9SC0/2 up t the islatin pints at 9SC5 and 9SC6. This cnfirms that bus discnnectrs 9SC5 and 9SC6 are pen n the cnductrs that 9SC0/2 has earthed. The islatin pints 9SC5 and 9SC6 are nw cnsidered cnfirmed. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 16 f 19

17 (c) Either earthing switch 9SC0/A3 r 9SC0/B3 may be clsed because the pen cnditins f 9SC6 and 9SC5 have already been cnfirmed (de-energised frm the busbars) and Disc 9SC1 is indicated as pen (de-energised frm the cable). Secure the Islatin and Earthing This is t be dne n the switchgear level by securing the three psitin switches 9SC1, 9SC5 and 96C6 in their pen psitins and securing earthing switches 9SC0/2, 9SC0/A3 and 9SC0/B3 in their clsed psitins Access t three psitin switches 9SC1, 9SC5 and 9SC6 is nt prvided in the abve switching sequence and therefre the manual peratin f the switches is nt available and the lcks prvided n the manual peratin pints shall remain intact with apprpriate tags applied. Electrical peratin f all 3-psitin switches shall be disabled in the lcal cntrl cubicle by the pening f links and applicatin f tags. Prepare the Area fr Access Authrity Issue If earths are required t be remved t enable testing f the abve equipment, high vltage access t the 3- psitin switch will need t be requested r (and mre likely) the external earth cnnectins t the GIS may be remved. These shall nly be remved under testing high vltage access cnditins. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 17 f 19

18 6.12. Haymarket 132kV GIS - Feeder Only (9SC feeder) Refer t Haymarket HVOD diagram HYM The fllwing switching sequence is an example that applies the principles fr islatin and earthing when using remte r lcal peratin f switchgear. This switching sequence assumes that the feeder will be ffladed by TransGrid, islated at the remte end by AusGrid, then islated and earthed by TransGrid and finally earthed by AusGrid. Nte: All checks f islatin shall be perfrmed using ALL three phases. All lcal and remte peratins are cmmn except thse specifically stated as Lcal Operatin r Remte Operatin Switching t Islate and Earth Operative step Operating functin Secndary actin and explanatin OFF-LOAD 9SC Open CB 9SC2 Use CB status and current indicatins t ensure ff-lad Request AusGrid t Islate 9SC feeder within their system AusGrid are required t islate the transmissin line frm all surces f supply within their system using a prcedure acceptable t TransGrid. Receive clearance frm AusGrid that 9SC feeder is islated within their system ISOLATE AND EARTH Open Disc 9SC1 (Nte 1) Lcal Operatin : Ensure visible break exists Remte Operatin : Use discnnectr status indicatin t check change f status Check feeder de-energised Use feeder vltage indicatin Open CB 9SC2 (Nte 2) Use CB status indicatin t check change f status Clse E/S 9SC0 (Nte 3) Use earthing switch status indicatin t check change f status NOTES: (a) The effectiveness f the 9SC1 pint f islatin is cnfirmed by: The switch psitin indicatin (r visible break if perating lcally), (b) Circuit breaker 9SC2 may be left in either the pen r clsed psitin as far as this prcedure is cncerned. (c) Earthing switch 9SC0 is an integral earthing and shrt-circuiting device with adequate fault making capacity. Earthing switch 9SC0 may be clsed because the HV cnductrs are indicated as de- energised frm the: Busbars by discnnectr indicatin r visible break; and Transmissin line by the islatin clearance frm AusGrid Secure the Islatin and Earthing This is t be dne n the switchgear level by securing the three psitin switch 9SC1 in the pen psitin, securing earthing switch 9SC0 in the clsed psitin and islating the feeder CVT. Access t three psitin switch 9SC1 is nt prvided in the abve switching sequence and therefre the manual peratin f the switch is nt available and the lcks prvided at the manual peratin pint shall remain intact with apprpriate tags applied. Electrical peratin f the 3-psitin switch and earthing switch shall be disabled in the lcal cntrl cubicle by the pening f links and applicatin f tags. Advise AusGrid that the transmissin line is islated and earthed. This switching sequence nly prvides access t the transmissin line, if access is required t the TransGrid bay equipment further islatin and earthing steps will be required. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 18 f 19

19 6.13. Haymarket 330kV GIS - Bay Equipment Only (CB 5412A) Refer t Haymarket HVOD diagram HYM The fllwing switching sequence is an example that applies the principles fr islatin and earthing when using remte r lcal peratin f switchgear. All checks f islatin shall be perfrmed using ALL three phases. This example assumes that the N.1 and N.3 transfrmers will remain energised during an utage f the bay equipment. All lcal and remte peratins are cmmn except thse specifically stated as Lcal Operatin r Remte Operatin Switching t Islate and Earth Operative step Operating functin Secndary actin and explanatin OFF-LOAD CB5412A BAY Open CB 5412A Use CB status + current indicatins t ensure ff-lad ISOLATE AND EARTH Open Disc 5417 (Nte 1) Lcal Operatin : Ensure visible break exists Remte Operatin : Use discnnectr status indicatin t check change f status Open Disc 5437 Lcal Operatin : Ensure visible break exists Remte Operatin : Use discnnectr status indicatin t check change f status Clse E/S 5410/A2 (Nte 2) Use earthing switch status indicatin t check change t clsed status Clse E/S 5410/A3 Use earthing switch status indicatin t check change t clsed status NOTES: (a) The effectiveness f the 5417 and 5437 pints f islatin are cnfirmed by: The switch psitin indicatin (r visible break if perating lcally), (b) Earthing switches 5410/A2 and 5410/A3 are integral earthing and shrt-circuiting devices with adequate fault making capacity. Earthing switch 5410/A2 may be clsed because the HV cnductrs are indicated as de-energised frm: N.3 Tx by discnnectr indicatin r visible break, and N.1 Tx by discnnectr indicatin r visible break. Secure the Islatin and Earthing This is t be dne n the switchgear level by securing the discnnectrs 5417 and 5437 in their pen psitins and securing earthing switches 5410/A2 and 5410/A3 in their clsed psitins. Operating Prcess fr Access t Gas Insulated Switchgear Revisin N: 2 Page 19 f 19