Challenges

• Using the ETAP Power Simulator and its primary analysis tool to address distributed energy resources and the growing incursion of microgrids in the national territory.
• Modeling the physical pilot grid to enable the analysis of grid and equipment behaviors. The microgrid project comprises various energy resources, including a battery energy storage system, which will serve as the primary source of the project's photovoltaic generation through solar panels and inverters. The diesel generation serves as a backup power source, while conventional generation is supplied through a connection to the public utility grid.
• Creating a virtual model in the ETAP software, enabling analyses, simulations, and testing the planned solutions.
• Simulating load profiles and different types of loads, to test and benchmark the performance of the energy resources and associated controls in the planned microgrid. Developing analysis scenarios for different electrical network models.
• Test the capabilities for islanded and grid connection operations. The project is part of a grid operator initiative to develop a microgrid laboratory and a test bench for distributed energy resources technologies, aiming to implement solutions on a significant scale in multiple locations throughout the country. Therefore, all tests should be performed.
• Selection of the proper technologies, hardware, and equipment to comply with the expected performance and even more grid code regulations.
• Appropriately integrate and achieve sufficient interoperability among technologies from different vendors, delivering comprehensive and effective control and monitoring strategies for the microgrid.
• Delivering professional reports to the grid operator to facilitate decisions.

Selected applications

As a base software, they utilize ETAP Digital Twin for grid modeling and analysis and ETAP Power Simulator to simulate electrical network behavior.

Protective Device Coordination was performed using the Star module in the ETAP software. The ETAP Microgrid Controller was utilized with integrated digital twin capabilities.

Main Customer Benefits

• Building the physical model and its virtual Digital Twin model on ETAP. The microgrid model for conducting the impact studies was created in ETAP Power Simulator. All the information supplied by the grid operator, regarding the local grid and the technical information and data sheets collected from the several equipment and hardware that were projected to be installed in the microgrid, was used.
• Using the ETAP Microgrid Controller, including the Digital Twin model for evaluation, testing, and fine-tuning optimal controller settings, was crucial for the customer in terms of effectiveness. They developed and tested the digital twin first in a simulation environment. Then they deployed the digital twin to the controller hardware and tested it within a Software-in-the-Loop test setup. It reduces the time spent on testing, improves the quality of tests, and simplifies the validation of complex systems. 
• In the Steady State Simulation, nine scenarios for the grid-connected microgrid were evaluated, considering combinations of maximum, medium, and minimum load demand and photovoltaic generation levels as well.
• Fifteen scenarios were performed for the islanded mode microgrid, considering combinations of maximum, medium, and minimum electronic load demand and different combinations of energy resources, working at the same time. In other simulated scenarios, voltage levels, conductors, transformer loadings, power factors, and general power flows through various locations in the building's electrical system were analyzed. Results showed that incorporating the microgrid into the building's electrical system does not pose a risk to normal operation conditions.
• For the Short Circuit Analysis, three scenarios were evaluated. Two of them were switching between the two available feeder circuits in the building. Three-phase, two-phase, and one-phase ground faults were assessed. Circuit breaker and busbar duty capacities were also evaluated. In the third scenario, the short-circuit levels were evaluated for the microgrid in the islanded mode. Results indicate that the short-circuit levels are within the equipment's endurance capacity or the safety operation range in the microgrid.
• Protective Device Coordination was performed using the Star module in ETAP, based on the IEEE Standard 242 of 2001. It was necessary to comply with the current Colombian Grid Code and regulations, like Agreement CNO 1322, ANSI 81 under and over frequency, ANSI 44 negative sequence, ANSI 40 loss of excitation, ANSI 59 and ANSI 27 over and under voltage, ANSI 78 phase angle, ANSI 32R reverse power, and finally ANSI-ISLA islanding ROCOF operation.
• Based on the safety limits defined in the equations of the standard IEEE 80 of 2013, the ETAP Ground Grid module was used for verification of Ground Grid System. The maximum ground potential range step and touch voltages were computed. The voltage distributions were graphed for a comprehensive analysis. Results indicated that the incorporation of the microgrid increases the short-circuit levels. However, the touch and step voltages were kept within safety limits.
• A harmonic analysis and transient stability were conducted to analyze its impact on the electrical system. Three scenarios for the microgrid connected mode were simulated, and four scenarios for the microgrid islanded mode were simulated, considering different combinations of energy resources to meet or cope with the demand of the electronic loads. Results showed that harmonic constraints in voltages and currents in the system are below the maximum limits. Frequency and voltage limits based on Colombian Regulations were correct. 025 standard of 1995, CREG Resolution 070 of 1998, and NTC 1340 were verified and not to be surpassed.
• High-quality analysis reporting with an optimal dose of information, and high-level quality of studies and reports.
• Easy generation of similar scenarios by editing already existing scenarios.

Opinions

By Mr. Juan Carlos Serna Marin, Electrical Engineer, PTI SA

In the ETAP solution, we can utilize the same model employed in the studies stage to emulate the real system and interact with control devices using the concept of a digital twin. ETAP uses integrated software-in-the-loop technology to emulate system and control performance. It is possible to benchmark several operation scenarios, perform changes to the system on the go, and re-test control strategies.
By Mr. Juan Carlos Serna Marin, Electrical Engineer, PTI SA