EARTHING DESIGN, PROTECTION & TESTING

APD are active members of a number of industry panels throughout Australia and this ensures that we not only keep up to date with the latest policy and technical design standards but it also presents us with an opportunity to provide our input and recommendations on any proposed changes. Some of the industry memberships that APD currently hold are listed below:

• Urban Development Institute of Australia (UDIA)
• Electric Energy Society of Australia (EESA) (Committee)
• Engineers Australia (Divisional Committee)
• Down to Earth Conference (DTEC)
• The Australian Power Institute (API)
• CDEGS User Group Australia (Chair)
• CIGRE Australia
• Institute of Electrical and Electronics Engineers (IEEE)
• The Australasian Corrosion Association INC

We have substantial experience in ensuring that new electrical infrastructure installed on HV, MV and LV systems will satisfy the specific utility/client requirements as well as comply with Australian and International technical standards and regulations including; AS2067, AS3000, AS7000, AS3007, AS4853, AS3835, ENA EG1, ENA EG0, IEEE 80 and IEEE 81.

APD have the know-how and track record of earthing design and field testing for a wide variety of electrical installations at high, medium and low-voltage, including:

• Large zone substations to compact kiosks (220kV – 415V)
• Transmission & distribution overhead lines & underground cable
• Power stations (thermal units and large-scale PV solar farms)
• Electrical reticulation systems in mining plants and land development projects
• AC & DC overhead traction system for railway networks
• Induced voltages on gas / water pipeline & apparatuses, conveyors, fences, etc.
• EPR testing on telecommunication assets (including NBN nodes)

Our capability in design and field testing extends to all phases of a project, including:

SOIL RESISTIVITY MEASUREMENTS

• Undertake Dial Before You Dig (DBYD) and prepare site specific test plans
• Carry out the soil resistivity measurements
• Establish the soil model using CDEGS software package

DETAILED EARTHING DESIGN

• Review the network and determine earth fault parameters
• Determine the statutory regulations and safety limits
• Earth grid conductor sizing
• Earthing system arrangement for HV, MV and LV networks
• Prepare drawings (earth grid layout and bill of materials)
• Develop detailed CDGES model and assess step and touch voltage hazards
• Investigate Earth Potential Rise (EPR) for third party infrastructure
• Assess step and touch voltage hazards on metallic pipes and apparatuses
• Modify the earthing design to address compliance issues and meet safety limits

EPR/LFI HAZARD ASSESSMENT

• Investigate transferred (EPR) and Low Frequency Induction (LFI) hazards from neighbouring zone substations, transmission lines and other installations
• Assess electrostatic induction & charging on metallic assets
• Undertake electromagnetic field studies in compliance with ARPANSA guidelines
• Develop Safe Work Method Statement (SWMS) and Safety in Design documents

ON-SITE AUDIT & REPAIR

• Visual audit under initial commissioning phase or periodic integrity checks
• Check compliance and accuracy of as-built drawing and red-line mark-ups
• Check condition of earthing conductors & connections, earth electrodes, bonding conductors, surface layer materials, and perimeter fences & gates
• Check the HV/MV/LV earthing arrangements, bonding of metallic pipelines, control / telecom earthing, lightning protection and corrosion protection units
• Visual inception of the site and identify 3rd party metallic objects subject to EPR
• Address compliance issue and make repairs on site.

FIELD COMPLIANCE TESTING

• Earth grid continuity testing
• Current injection testing to measure step and touch potential hazards
• Fall of potential to measure earth grid resistance
• EPR measurement for telecom (nbn) nodes
• Injection testing to assess transferred voltages on to third party infrastructure
• Step and touch hazard assessment on overhead railway traction installations
• Measure local earth grid resistance for lightning protection systems
• Post analysis of site measurements and preparation of compliance reports.

In addition to detailed earthing design studies, APD offer other engineering services relevant to the earthing system, including lightning protection design as per AS 1768 and lighting design as per and Australian Standard client requirements.

LIGHTNING PROTECTION DESIGN

• Lightning protection requirements in compliance with AS1768
• Detailed risk assessment and project specific designs
• Using SES Shield-3D software to carry out Rolling Sphere or Basic Impulse methods
• Powerline earth wire shielding angle and critical back flashover-voltages.

LIGHTING CALCULATIONS & DESIGN

• Lighting equipment specification
• Appropriate lighting category selection for substations, footpaths, roadways etc.
• Orientation and tilt position of lights in various applications
• Quantify compliance with glare restrictions
• Modelling and LUX level mapping using AGI32 and other software.

INSULATION COORDINATION STUDIES

• Lightning overvoltage studies – detailed modelling of using ATP Draw, PSCAD EMTC and other software
• Capacitor switching, transformer energisation, load rejection and earth fault over voltage studies and estimation of failure rate
• Lightning strike insulation studies and selection of surge arrester
• Point-on-wave and circuit breaker TRV studies.

NICHE EARTHING RELATED SERVICES

• Incident / Safety Investigations
• Railway AC and DC Traction Systems
• Earthing design and field testing for large-scale renewable energy systems (large PV solar farms) and battery storage units
• Corrosion Assessments and Cathodic Protection Systems
• Safe Work Method Statement (SWMS) and Safety in Design documents
• Soil Thermal Resistivity – Field and Laboratory Testing.

APD’s earthing team hold a comprehensive suite of testing and commissioning equipment which includes:

• Red Phase 4046, 4025E & 4047/C (High-current earth injection test set)
• Mitton LCI 2000B & TVM1100 (Low-current earth injection test set)
• Mitton ET1000 (Earth Tester/Micro-Ohmmeter)
• Omicron CPC100 (Primary injection Kit)
• Omicron CP CU1 (Overhead Line Parameter & Earthing System Analyser)
• Omicron CP TD1 (Leakage reactance & insulation conditions tester)
• Omicron CP CB1 (2KA Current injector)
• Omicron CMC356 (Secondary Injection Kit)
• Megger DLRO10 micro-ohmmeter (ductor tester)
• Megger DET2/2 soil resistivity tester
• Fluke 1625 soil resistivity tester
• Fluke 376 High current clamp meter soil resistivity testing

We also own and have expertise in operating the following earthing-related software packages:

• CDEGS Software Package (full suite including SESSheild-3D)
• PSCAD/EMTDC
• ETAP with Cable Thermal Module
• SKM Power Tools (PTW)
• AGI32
• DIgSILENT PowerFactory (load flow, protection dynamic and EMT modules)
• PSS Adept
• PSS/E and PSS Sincal
• CYMCAP
• PowerCAD
• Microstation V8i
• Autocad