Review Of Substation Grounding Practices, Safety And Constructability .
Review of Substation Grounding Practices,Safety and Constructability EnhancementsAuthors: V. SIMHA, X.WU, M.THAKUR
AgendaGrounding Study and Analysis: Substation Grounding Practices Grounding Concepts – GPR and Touch Potential AEP Innovative Grounding Study MethodsGrounding Installation: Traditional Approach and Challenges Grounding Application and Installation Change ManagementTesting: Grounding Integrity TestingConclusion and Future Vision:
AgendaGrounding Study and Analysis: Substation Grounding Practices Grounding Concepts – GPR and Touch Potential AEP Innovative Grounding Study MethodsGrounding Installation: Traditional Approach and Challenges Grounding Application and Installation Change ManagementTesting: Grounding Integrity TestingConclusion and Future Vision:
Substation Grounding PracticesCategory DescriptionIEEE 80 - 2013AEP DESIGN METHODSCalculation MethodUses hand calculation, utilizingequations to calculate an actual valueof a touch potential and a steppotential at one point on top of thesurface (not the entire surface area).The threshold values for the touch andstep potentials are also handcalculated for comparison.Use computer algorithms toaccurately simulate the siteconditions,powersystemconfigurations, power systemoperations, and prevailing orforecasted fault currents withclearing times – and determine theactual potentials throughout thesurface, then compares them tothreshold.Soil Model, Resistivityand ThicknessUses uniform soil model with oneresistivity value.Fault Clearing timeA single fault clearing timeconsidered in the hand calculation.Split factor calculationUtilizes pre-determined split factorcurves (that may not be applicable to aspecific station) to determine the gridcurrent and shield/neutral wirecurrents.Analysis is limited to a square orrectangular grid shape, and equal gridspacing.GPR impact on buried objects cannotbe analysed.Uses multi-layer soil model.Accounts for the prevailingresistivity and thickness of eachsoil layer.Segmented clearing times formultiple fault current magnitudescan be analysed.Calculates the split factor with theprevalent and pertinent conditionsto a specific station site (where theground grid is being designed).Grid shape and spacingBuried objectsTransfer PotentialisProvides minimum guidance ontransfer potential impact on aneighbor’s fence, and recommends theinsulation of a fence extending outsidethe substation area.Can analyse all grid shapes andsizes, with no limitation on gridspacing.Can analyse buried objects, such aspipelines, above ground hydrants,or telecom interface boxes.Can determine transfer potentialimpact on a neighbor’s fence,alongwithmitigationthatidentifies a non-metallic fencelocation and length that wouldmitigate the transfer potentialfrom the substation fence.
Grounding Concepts - GPR andTouch PotentialTouch potential illustration when a ground fault energizes the ground grid
Grounding Concepts - GPR andTouch PotentialTouch potential illustration when a ground fault energizes the fence/structure
Structure, Equipment, andFence grounds
AEP Innovative GroundingStudy MethodsSingle Injection method fault current distribution
AEP Innovative GroundingStudy MethodsMultiple Injections method fault current distribution
AgendaGrounding Study and Analysis: Substation Grounding Practices Grounding Concepts – GPR and Touch Potential AEP Innovative Grounding Study MethodsGrounding Installation: Traditional Approach and Challenges Grounding Application and Installation Change ManagementTesting: Grounding Integrity TestingConclusion and Future Vision:
Traditional Approach, andChallengesExothermic Weld and Safety Incidents
Traditional Approach, andChallengesChallenging site installation (top), quality comparison – welded versus swage (right)
Traditional Approach, andChallenges Welding process, and safety Weld quality and consistency issues Challenges in wet conditions – over 200 wetdays in OH. Safety incidents Increasing number of projects A standardized approach
Grounding Application andInstallationTypical Swage connectors - for 4 / 0 (left), for ground rod (right)
Grounding Application andInstallationSwage is the generic term used for a cold forging process when the dimensions ofthe conductor and connector are altered in a tool die with equal compressive forceswhile making the connection.Head Assembly (left), Gauge (right)
Change ManagementWhy? Focus on Safety, Constructability, EfficiencyHow? On site training and awarenessTracking ProjectsPeriodic collaborative meetingsDocumenting the concerns, and responses.Determining an issue, and possible resolution.
AgendaGrounding Study and Analysis: Substation Grounding Practices Grounding Concepts – GPR and Touch Potential AEP Innovative Grounding Study MethodsGrounding Installation: Traditional Approach and Challenges Grounding Application and Installation Change ManagementTesting: Grounding Integrity TestingConclusion and Future Vision:
Grounding Grid IntegrityTestingCorroded ground conductorGrounding integrity testing Impedance values compared after successive yearsof testing at the same location. Change in impedance values indicates the groundconductor health.
Grounding Grid IntegrityTestingGrounding plan drawingGround grid integrity testing set-upTest LeadRedMain GateMain GateMain GateMain GateTest LeadBlackCB-GSouth FenceNew Control HouseSoutheast FenceTest round grid integrity test dataReactancemΩ48.710468.6200
AgendaGrounding Study and Analysis: Substation Grounding Practices Grounding Concepts – GPR and Touch Potential AEP Innovative Grounding Study MethodsGrounding Installation: Traditional Approach and Challenges Grounding Application and Installation Change ManagementTesting: Grounding Integrity TestingConclusion and Future Vision:
Conclusions and Future Vision Recommends an optimally-designed safe ground grid that usesaccurate modeling techniques, and enables possible material andlabor savings – while meeting all IEEE 80 safety requirements. The use of a swage ground connection improves field safety,facilitates a better quality installation, improves constructabilityand project efficiency with time and labor savings in all-weathersite conditions. This paper also details a ground grid integrity testing method thatcan be deployed to track the health of the ground gridconductors over the service lifetime.
Bibliography[1] IEEE 80 – 2013, Guide for Safety in AC Substation Grounding.[2] X.Wu, V.Simha, R.J.Wellman, “Optimal Ground Grid Design for Large EHV Substationswith Autotransformer”, Publication No. 978-1-4673-8040-9/15/, IEEE PES General Meetingin Denver, CO in July 2015.[3] CDEGS Software Package, Safe Engineering Services & technologies ltd., tm.[4] ASPEN Software, Advanced Systems for Power Engineering, Inc., link:www.aspeninc.com/web.[5] BURNDY Exothermic Grounding, link: ermic-grounding.[6] DMC Power Swage Ground Connectors, link: dmcpower.com/connectors/groundconnectors.
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Grounding Study and Analysis: Substation Grounding Practices Grounding Concepts - GPR and Touch Potential AEP Innovative Grounding Study Methods Grounding Installation: Traditional Approach and Challenges Grounding Application and Installation Change Management Testing: Grounding Integrity Testing Conclusion and .
Cost Effective Grounding Grid Design for Substation Soni M , Dr. Abraham George . Abstract: Well-designed grounding system is very much essential as far as the safety of the crew and the substation equipments are concerned. Optimal design of grounding system for a substation is complex due to the involvement of numerous parameters.
The substation ground grid design is based on the substation layout plan. The following points serve as guidelines to start a grounding grid design: 1. The substation should surround the perimeter and take up as much area as possible to avoid high current concentrations. Using more area also reduces the resistance of the grounding grid. 2.
buried depth of the grounding grid, the resistance reducing effect is not obvious, in particular to areas with high soil resistivity. Therefore, in general, this method is not adopted in the engineering. The buried depth of the substation grounding grid is about 0.8 m generally. Long vertical grounding electrodes, blasting grounding and deep well
Electrical Substation Configuration Effect on Substation Reliability . Courtney Otania and Kurt Vedros a. a Idaho National Laboratory, Idaho Falls, ID, USA . . Substation Level, Generic 4.931E-05 Busbar, Substation [7] 132 kV Busbars 1.507E-05 Control Panel Switchgear [2] C4-300 2.845E-06 .
substation neutral buses and substation grounding resistance values, 4) transmission lines with series capacitive compensation are omitted since series capacitors block dc flows, and 5) transformers are modeled with their winding resistance to the substation neutral when grounded. The determination of s depends on several factors, some of
In any substation, grounding system deserves considerable attention as far as performance and design are considered. So . the design of grounding grid should be such that total grounding system is safe and at the same time it is cost -effective. In recent years, a SF6 gas-insulated switchgear (GIS) indoor substation is adopted by power .
Keywords: Gaza, Grounding Grid, Ground Resistance, Substation, Step Voltage, Touch Voltage. 1. Introduction . Grounding is by far one of the most imperative aspects of electrical systems design the significance of which has attained modest mention. The design of the substation is complex and constitutes a copious number of interlinked
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