Arc Flash

• Power System Modelling and Analysis
• Arc Flash Risk Assessment and Mitigation Strategy Development
• Engineering Design for Hazard Mitigation
• Arc Flash labeling and Compliance Documentation
• Asset Upgrades and Cutover Planning
• Development of Arc Flash Management Programs

GPA was engaged by Santos to provide arc flash assessment services for the Santos Port Bonython facility. The investigations
presented several unique challenges due to aging electrical infrastructure, legacy equipment reaching the end of its
operational life, legacy protective devices with limited settings adjustment capabilities, and a high concentration of DOL motors
resulting in elevated fault levels which significantly limited options for risk mitigation.

GPA conducted a detailed site visit of the Port Bonython facility to collect data and verify the existing HV & LV network, ensuring that up-to-date information is utilised in the assessments.

As part of the project GPA provided the following services:

1. Developed a comprehensive arc flash assessment methodology aimed at assisting Santos in establishing site specific standards
2. Built and validation an accurate power systems model for the facility
3. Conducted detailed arc flash incident energy analysis, incorporating motor fault current contribution decay to ensure accurate estimation of incident energy levels.
4. Developed balanced remediation strategies using a combination of protection setting changes and relay upgrades.
5. Performed comprehensive optioneering for assets where arc flash risks could not be fully mitigated through protection measures

The Tesla Hornsdale Power Station is a 150 MW (194 MWh) gridconnected energy storage system located within the Hornsdale
Wind Farm in the Mid North region of South Australia. It is considered the world’s first “big battery”.

GPA was engaged by Tesla to perform an arc flash study for Hornsdale Battery Energy Storage Systems (BESS).

As part of the project GPA provided the following services:

1. Modelling of the BESS inverter stations
2. Evaluating the fault ride-through response characteristics of the BESS inverters and the impact of the same on the arc flash incident energy levels
3. A detailed arc flash study outlining the arc flash methodology, calculated incident energy levels, arc flash hazard risk category, PPE recommendations and arc flash labels for the BESS inverter stations
4. Recommendations for the mitigation and management of arc flash risk

Santos engaged GPA to perform power system analysis for the Devil Creek Facility. This included analysis of HV & LV switchboards
at the Devil Creek Power Station based on agreed operational scenarios with Santos.

As part of the project GPA provided the following services:

1. Development of Power System Model of the Gas processing facility and power station
2. Load shedding study involving dynamic simulation of the power system and analysis of the potential impacts of loss of generator on plant operations
3. Protection studies of various switchboards to improve protection grading and selectivity
4. A detailed arc flash study outlining the arc flash methodology, calculated incident energy levels, arc flash hazard risk category, PPE recommendations and arc flash Labels
5. Optimisation of protection settings to reduce incident energy levels wherever possible

The BHP Olympic Dam operation includes an extensive industrial electrical distribution network comprising of high voltage and low
voltage infrastructure which form an important part of the overall BHP Olympic Dam network.

GPA was engaged by BHP to provide arc flash assessment services for the surface processing facilities at Olympic Dam.

As part of the project GPA provided the following services:

1. Extensive, multi-phase site data collection process to validate and update the existing ETAP model
2. Identification of prohibited switching configurations that contributed to high fault levels and arc flash risk
3. Development of arc flash methodology outlining the approach, risk assessments and arc flash label contents to be adopted
4. Performed detailed incident energy analysis across various operating scenarios.
5. Developed comprehensive protection studies and mitigation strategies to reduce arc flash hazards and optimize protection coordination.

GPA is currently working with Santos to improve the operational safety of their electrical distribution assets at a number of their
upstream facilities in the Cooper Basin. The project involves multiple satellites and microgrids with standalone power systems
supplied by small synchronous generators or a combination of generators and PV/BESS systems. These facilities present unique
challenges due to limited fault levels, sparse distribution networks, and diverse operational configurations, making protection and arc flash mitigation complex.

GPA undertook a comprehensive approach to address these challenges:

1. Conducted thorough site data collection and validation to establish an accurate baseline for system modelling
2. Developed detailed power system models, incorporating generator fault current decrement characteristics and the current source behaviour of BESS and PV inverters to ensure accurate fault level and protection response assessments
3. Performed arc flash studies tailored to each site’s unique configuration to identify and quantify potential hazards
4. Developed and implemented a combination of protection setting adjustments, protective device upgrades, optical arc
   flash detection systems, and optimised switching configurations to mitigate high arc flash risks and enhance overall system safety

GPA Engineering was engaged by OZ Minerals to provide Arc flash
assessments for the HV and LV electrical assets installed across the
Prominent Hill mine facility in order to assess and manage risk to operations and maintenance personnel.

As part of the project GPA provided the following services:

1. Updates to the existing Prominent Hill power system ETAP model with the latest site information
2. A detailed arc flash study outlining the arc flash methodology, calculated incident energy levels, arc flash hazard risk category, PPE recommendations and arc flash Labels
3. Optimisation of protection settings to reduce incident energy levels wherever possible
4. General recommendations for the mitigation and management of arc flash risk

RMGE is an Australian first solar and storage hybrid project of it’s nature operating within the traditional energy arbitrage markets
(5 minute spot market pricing), as well as the AEMO Contingency Frequency Response Ancillary Services (FCAS) Markets. GPA has partnered with YES group as the detailed engineering designer for the RedMud Green Energy (RMGE) solar and BESS farms.

The RMGE projects presented several unique challenges typical of DC systems and PV installations, including:

1. Variable fault current characteristics of PV array (irradiance dependency)
2. Relatively high DC fault current from BESS
3. Bi-Directional Current Flow and complex fault interactions between AC and DC systems

GPA addressed these challenges through a structured, multi-phase approach:

1. Developed a tailored methodology for DC arc flash evaluation, drawing on industry-accepted approaches (Doan, Paukert,
   Stokes/Oppenlander) and guidelines from EPRI research
2. Assisted YES Group in developing comprehensive arc flash management plans for their operational facilities
3. Conducted in-depth modeling and analysis for each site, providing recommendations for hazard mitigation and control through a combination of engineering and administrative measures customized to meet client needs

GPA was awarded a contract by SA Water to conduct arc flash hazard assessment for their HV and LV electrical assets at a
number of pumping stations and water treatment plants in SA.

SA Water faced the challenge of managing a vast and geographically dispersed portfolio of electrical assets, many
of which were equipped with aging infrastructure and legacy protection relays with limited configuration capabilities. Additionally, SA Water sought GPA’s services for the development of their internal standards, policies, and procedures to assess, manage, and mitigate arc flash hazards effectively.

As a part of this engagement, GPA provided the following services:

1. Assisted SA Water with the development of their internal standards and procedures for arc flash risk management in alignment with industry best practices
2. Planned and conducted extensive site surveys and data collection across multiple geographically dispersed sites
3. Performed detailed arc flash modelling and incident energy analysis for each site, factoring in the limitations of aging equipment and the constraints of legacy relays
4. Provided optimized protection settings to reduce arc flash incident energy and classification where possible
5. Provided technical recommendations and guidance for the phased implementation of mitigation strategies and hardware upgrades where necessary