How AECOM uses ETAP to model and analyze a microgrid for a wastewater treatment plant

Power system modelling is just a representation of the power system electrical network in the form of a simulation model. Power system analysis is the calculation and simulation to verify that the electrical system, including its components, is correctly specified to perform and operate as intended. It should protect itself well in case of disturbances and short circuit faults.
Abinet Tesfaye Eseye, Microgrid Power Systems Lead, AECOM

AECOM developed a complete ETAP-based digital twin of the wastewater treatment plant microgrid to evaluate its electrical behaviour under realistic operating conditions. The study focused on validating feeder loading, equipment adequacy, fault current levels, voltage performance, mode-transfer behaviour, and DER coordination (PV, CHP, BESS, diesel). Using ETAP’s simulation and analysis capabilities, AECOM confirmed that the microgrid can reliably operate the plant - even at maximum loading - without relying on the utility grid.

AECOM is an American multinational infrastructure consulting firm headquartered in Dallas, Texas. Across the globe, their teams push the limits of what’s possible and build legacies for generations to come – the world’s longest cable-stayed bridge, record-breaking sports events, the largest greenfield port development mega project, life-sustaining disaster recovery programs, and the tallest tower in the Western Hemisphere. By harnessing the power of digital technology and the innovation of their technical experts worldwide, they deliver tailored solutions and transformative outcomes for their clients and the communities they serve. AECOM has more than 50,000 employees.

Location: Dallas, Texas, United States

Year: 2022

To create a microgrid model for emission critical facility and to provide calculations and validations of the power system

Challenges

  • Ensuring reliable power supply for a critical infrastructure facility operating in both grid-connected and islanded modes
  • Evaluating voltage regulation, transformer tap selection, and feeder loading across nine operating scenarios
  • Validating coordination among PV, CHP, BESS, and diesel generators during transitions and steady-state operation
  • Confirming breaker interrupting capacity, switchgear withstand limits, and overall protection adequacy
  • Simulating mode transfers between utility and islanded operation without compromising stability
  • Understanding the dynamic response of all DER units during contingencies and switching events
  • Testing the system’s ability to black-start and restore service after a complete outage

Which solutions did they choose?

Selected applications

AECOM applied multiple ETAP modules to build and validate the microgrid model:
  • Power Flow Analysis – Voltage regulation, equipment loading, transformer tap selection
  • Short Circuit Analysis – Fault-level evaluation and interrupting rating verification
  • Transient Stability – Dynamic behaviour of DERs and transition performance
  • Sequence of Operations – Validation of switching sequences, timing, and operational logic
  • Motor Acceleration – Assessing motor starting impacts under both grid and microgrid conditions
  • Digital Twin Technology – Providing a real-time, fully representative model for present and future analysis

Why do they use ETAP?

Main customer benefits

  • Accurate representation of the entire microgrid, allowing AECOM to validate multiple scenarios efficiently
  • Confirmed that the facility can operate at maximum demand without the utility grid, relying entirely on the microgrid
  • Optimized transformer tap settings, ensuring voltage remained within the 95–100% acceptable band
  • Validated DER interaction, including coordinated power sharing between PV, CHP, BESS, and diesel generators
  • No equipment overloads or rating violations, improving safety and operational confidence
  • Clear visibility into protection adequacy, ensuring breakers and switchgear function safely for all fault locations
  • Robust analysis of mode transfer behaviour, helping refine operational strategy and emergency response
  • Future-ready model, enabling advanced analysis such as protection coordination, harmonics, EMT studies, and power quality

What do they think about ETAP?

Customer perspective

 

Using ETAP, we modelled both grid-connected and islanded operation. We evaluated fault currents, voltage regulation, equipment loading, transformer taps, and DER coordination across nine scenarios. No major violations were identified, and the plant can reliably serve its maximum load even without the utility grid.
Abinet Tesfaye Eseye, Microgrid Power Systems Lead, AECOM


Videos

Modeling and Analysis of a Microgrid for a Wastewater Treatment Plant - AECOM

Engineering and operation objectives of mission-critical facilities require a reliable and secure power supply system. Microgrids have become the leading technological solution for a resilient and sustainable supply of electricity for critical infrastructures. This paper presents ETAP-based power system studies of a microgrid designed for a mission-critical facility, a wastewater treatment plant (WWTP). The microgrid consists of a behind-the-meter (BTM) solar photovoltaic (PV) system, a battery energy storage system (BESS), a combined heat and power (CHP) generator, and standby diesel generators. We modeled this microgrid by leveraging the ETAP software and performed power system studies for both grid-connected and islanded modes of operation. Several scenarios were created based on different loading conditions and power source combinations, which are utilized to validate the power system studies. We will discuss the model of the power system investigated, operational strategy and sequences of operation, findings, challenges, lessons learned, and future works.


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