How Nexamp Energy uses ETAP for higher quality and accuracy DC Arc Flash Analysis in BESS

Let’s understand engineers' challenges when calculating DC AF incident energy. We will see how ETAP solves these challenges as we move through our presentation.
Mr. Albert Marroquin, Engineering Division Manager for Dynamics and Electrical Safety Products at ETAP

This case study discusses the modeling of the DC Battery Energy Storage System. These systems are crucial for managing energy supply and demand, particularly with renewable energy sources such as solar and wind, which can be intermittent. Large grid-scale BESS installations require careful modeling to ensure efficiency while maintaining safety for maintenance purposes. This use case describes a real-world solution implemented in a California facility.

Nexamp Energy is a clean energy company that deploys and operates solar energy assets. It offers community solar programs, energy storage solutions, and power purchase agreements to provide savings and sustainable energy options for businesses and homeowners. Nexamp primarily serves the renewable energy sector, delivering large-scale solar projects and energy storage systems. It was founded in 2007 and is based in Boston, Massachusetts. Nexamp operates as a subsidiary of Mitsubishi and has offices throughout the United States.

Location: Boston, Massachusetts, USA

Year: 2024

Ensure safe and efficient operation of the existing battery station

Challenges

  • To find accurate electrical calculation methods for existing DC Battery Energy Storage Systems, such as short-circuit, arc flash, and thermal calculation.
  • The different types of batteries connected in the facility should be modeled accordingly, with their specific properties, like resistance, inductance, operating voltage level, and battery age. Every type of battery, including lithium-ion, lead-acid, and nickel-based, has its unique characteristics.
  • Various wire configurations, including series, parallel, and bus systems, should be integrated into the simulation.
  • Feasibility studies should be conducted on different scenarios and methods of predicting high incident arc flash energy events.

Which solutions did they choose?

Selected applications

They selected the ETAP software, featuring DC Load Flow, DC Short Circuit, DC Arc Flash, and ETAP Digital Twin, as their leading solution. 

ETAP ensured compliance with all needed electrical standards for designing and calculating the battery installation.

Why do they use Etap?

Main Customer Benefits

  • Digital modeling of the actual battery storage with conductors, busbars, and locations.
  • Users can rapidly modify the system layout to simulate various battery configurations and conductor arrangements, facilitating proactive risk management and design optimization. This enables easy management of multiple scenarios by adding or deleting actual equipment symbols and adjusting the layout.
  • Analysis of critical issues like DC short circuit, arc flash, and arc duration using only one workspace.
  • ETAP’s Transient DC AF Solution for Battery Energy Storage Systems, utilizing IEC 61660, helps estimate incident energy more accurately.

What do they think about ETAP?

Opinions

The biggest challenge is the lack of accurate methods. Engineers had relied on the Max Power method for many years, which could yield overly conservative and even under-conservative results.
In this simulated test, conducted using ETAP software, a lithium-ion battery bank was simulated as having a fault, and the DC Arc current was plotted as a function of time. As shown here, the rise time constant of lithium-ion batteries is significantly shorter than that of other battery types, such as lead-acid.
Mr. Albert Marroquin, Engineering Division Manager for Dynamics and Electrical Safety Products at ETAP

The type of installation determines the choice of calculation method and the associated hazard level. The various types of battery chemistries used have significantly different short-circuit current behavior. To determine the clearing time results for the Fuse C-areas, it's key to decide on the key parameters on which DC Arc Flash calculation methodologies are based.  
Mr. Terry McKinch, Electrical Safety Manager at Nexamp Energy Inc.



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