Background

Client: Undisclosed
Industry: Data Centres
Location: Africa
Date: October 2024

Project Overview

EPS provided a protection and arc flash study for an off-site manufacturer’s data centre in Africa, which is currently in the design phase. We performed various power system studies and arc flash analyses for the client’s entire MV (Medium Voltage) and LV (Low Voltage) systems.

Scope of Work

Our electrical engineering team successfully tackled the challenge of optimising a client’s Data Centre electrical infrastructure. Through meticulous analysis and expert implementation, we ensured the system’s efficiency and safety, meeting the highest industry standards. Our comprehensive approach included conducting a suite of power system analyses, encompassing load flow, short circuit, protection coordination, and arc flash energy calculations.

The scope of our work extended beyond mere analysis, demonstrating our capability to deliver end-to-end solutions for complex electrical systems. By leveraging our extensive experience and cutting-edge methodologies, we provided the client with a robust, reliable, and future-proof electrical infrastructure. This project showcases our team’s ability to handle mission-critical facilities, underscoring our commitment to excellence in electrical engineering for data centres and other high-performance environments

• Determining maximum load flow around the network
• Maximum and minimum initial symmetrical fault levels and asymmetrical peak fault levels – according to the IEC 60909 standard.
• Overcurrent and earth fault protection coordination
• Calculating differential protection settings
• Calculating potential arc flash levels with recommended protection settings – according to the IEEE 1584 standard.

Utilising state-of-the-art ETAP 22.5.0 software, our engineering team conducted comprehensive studies that yielded detailed insights into the electrical system’s performance. This advanced analytical approach not only provided our client with a thorough understanding of their infrastructure but also ensured full compliance with stringent regulatory standards and safety requirements. Our expertise in leveraging cutting-edge tools like ETAP demonstrates our commitment to delivering precise, reliable, and compliant electrical engineering solutions for mission-critical facilities.

Project Highlights

1. Load Flow Analysis

Objective:

To verify that voltage levels remain within regulatory tolerances and that all electrical equipment should operate without being overloaded.

Methodology:

The load flow analysis investigated three load flow criteria to assess the capability and generation of the data centre for various generation and network configuration scenarios:

• Total Busbar and branch loading
• Total Transformer loading
• Generator & UPS Loading

Results:

Voltage levels across the facility were confirmed to meet regulatory tolerances of +6% and -10%. Transformer sizing was deemed adequate to manage the site’s load without any signs of overloading.

2. Short Circuit Analysis:

Objective:

To evaluate the short circuit currents and verify their compatibility with system equipment and fault-clearing capabilities.

• Obtained the short circuit current magnitude at each point in the power system.
• Compared the calculated fault current to the ratings of the installed equipment to verify that the equipment ratings are adequate to handle the short circuit current.
• Supported proper selection of circuit protection equipment.

Results:

Short circuit currents on both the MV and LV systems were within safe operating limits for the facility’s maximum Break (I’’K) and Make (Ip) currents, ensuring the integrity of protective devices and switchgear under fault conditions.

3. Arc Flash Study

Objective:

To assess incident energy levels and ensure personnel safety under fault conditions.
Methodology:

Calculated potential arc flash energy levels with the protection settings as they are at present.
Provided enhanced protection settings to reduce arc flash energy levels around the network.
Provided recommendations for Personal Protective Equipment (PPE)
Proposals for labelling of equipment

Results:

The study indicated a worst-case Incident Energy (IE) of 39.75 Cal/cm² of all power generation scenarios and network configurations at the load-side, this high IE level was partly attributed to high fault current levels and a low disconnection time of 0.8 seconds.

Per NFPA 70E guidelines, this necessitates the provision of arc flash PPE to be worn to minimise the likelihood of the operator receiving 3rd-degree burns should an arc flash occur. According to the NFPE 70E standard, this IE level requires personnel to wear the following PPE:

• Arc-rated clothing with an arc rating equal to or greater than the estimated incident energy
• Long-sleeve shirts and pants or coveralls or arc flash suits
• An arc-rated arc flash suit hood
• Arc-rated outerwear (e.g., jackets, parkas, rainwear, hard hat liner)
• Arc-rated gloves or rubber-insulating gloves with leather protectors
• Hard hats, safety glasses, or safety goggles
• Hearing protection
• Leather footwear

4. MV & LV Protection Settings and Coordination

Objective:

To ensure effective grading and coordination for both MV/LV systems, enabling reliable fault isolation while minimising unnecessary shutdowns.

• Protection Relay Settings: EPS determined the optimal protection relay settings based on the relays provided by the client, achieving effective grading and coordination.
• Time-Current Characteristics (TCCs): Detailed TCC curves were provided, demonstrating adequate coordination had been achieved. This allows for selective fault clearance across the system.

Key Findings and Outcomes

• Regulatory Compliance: The power system operates within regulatory limits for voltage tolerances and equipment loading.
• Efficient Fault Management: Both MV and LV systems are capable of safely managing fault conditions within their rated current limits, ensuring operational safety.
• Arc Flash Hazard Control: Personnel safety measures were outlined, especially considering the 39.75 Cal/cm² incident energy during worst-case scenarios.
• Protection Coordination Report: EPS delivered a detailed report outlining potential protection coordination issues and recommendations for future considerations.
• Recommendations for Future Maintenance: Based on the findings, EPS advised the client on key areas for ongoing maintenance and monitoring, ensuring optimal performance and safety for the power system as the data centre’s operational demands evolve.

Your Trusted Partner for Innovative Data Centre Solutions

At Engineering Power Solutions (EPS), we leverage cutting-edge power system modelling, in-depth analysis, and expert electrical safety practices to deliver robust, compliant, and future-proof solutions for data centres across the UK and beyond. Whether you are looking to enhance system reliability, integrate renewable energy, or ensure compliance with safety standards, our team is here to help.

Contact us today to discuss how EPS can support your next data centre project. Let’s create safer, more efficient electrical systems together.

Additional Resources

• Power System Studies Capabilities
• Arc Flash Studies Capabilities
• Data Centre Services Overview