How EPSOL Mitigated Total Harmonic Distortion THD Using ETAP Software in a Steel Plant

After one year of working intensively, the final power factor was about 0.97 and a THD, total harmonic distortion of 5.98. So, it was a very intense project, and the use of ETAP was a real game changer. This is a very powerful tool. The first stage was updating the single-line diagram. Because this plant was very old, it was about 52 years old, so we had to make everything from scratch. We started from zero and were given the extensive ETAP library, which enabled us to model the electrical factory network.
By Carlos Moran Ramirez, Project Manager at EPSOL

In this case study, we show the necessary stages to comply with the technical criteria established in the Mexican Grid Code. The case presented is a steel manufacturing plant with intensive use of induction furnaces. THD exceeded the Grid Code's limits. This presentation will highlight the compliance, diagnosis, engineering (studies of electrical power systems using ETAP), and equipment designed to comply with the technical criteria and mitigation. ETAP was used to size a filter to mitigate harmonics, change transformer type, and improve electrical parameters.

Epsol Energy & Power System serves the energy and power systems industry, providing services such as project management, construction of electrical substations, charging stations for electric vehicles, photovoltaic system integration, and compliance management with electrical interconnection standards. EPSOL provides the necessary expertise to deal with problems in the distribution and transmission of energy. Their solutions ensure continuity and reliability in the Electric Network.

Location: Puebla, Mexico

Year: 2021

Analyzing and implementing a new harmonic mitigation system for an old steel plant to comply with the Mexican Grid Code

Challenges

  • Diagnosing, why a very high level of Total Harmonic Distortion of about 12.48, THD, was noted in the electrical network.
  • Identify the impact of different equipment, provoking instability of the system. Steel plant uses lot of induction furnaces.
  • Single-line diagram preparing to analyze the existing system and make improvements. There was not an actual network topology drawing. To model the electrical factory network with all equipment and parameters.
  • Performing a power quality analysis required by the Mexican Grid Code. Client didn't have any studies on short circuits and electrical protection at all.
  • Measuring of real electrical data and network performance to understand what should be improved to comply with the Mexican Green Code.
  • Find the procedure that designers can use to calculate and analyze the harmonic for the old steel plant. The old steel plant worked with old equipment, which not guarantee the appropriate quality.

Which solutions did they choose?

Selected applications

They have used the full ETAP solution from Modeling to Operation. Harmonic Analysis Software module was used strongly to simulate harmonic current and voltage sources, identify harmonic problems, reduce nuisance trips, design and test filters, and report harmonic voltage and current distortion limit violations.

The ETAP solution guarantees compatibility with actual standards for electrical systems in the steel industry. 

Why do they use ETAP?

Main Customer Benefits

  • Easy modeling of the existing system with all parameters from the field. All concerned symbols use electrical parameters. Simulating of the new, updated system, with proposed by Epsol new equipment.
  • Epsol divided the process of improvement into stages: initial diagnosis, power quality analysis, compliance review and conclusions, fulfilment of technical criteria, modelling, commissioning, and verification of the solution. ETAP was used in every stage.
  • Thank to ETAP analyzes and simulations, they decided to install a new transformer. Steel plant had to buy a new one, to meet growing needs. The new, dry-type transformer was modeled using ETAP. All the calculations and analyzed were made in ETAP, to choose right one. They made a lot of flow, short circuits, electrical protection coordination, arc flash, and harmonics studies to confirm selection.
  • They have chosen a special solution, Elspec harmonic filter, made in Israel, to decrease level of harmonics. They also used ETAP's harmonic module to meet the technical criteria and locate a harmonic filter in the best area.  After installation of the filter, a decrease in the total harmonic distortion THD was from about 12.48 to 5.9. Epsol provided the best technical and economic proposal.
  • They prepared in the ETAP a model of the harmonic filter, with using of 11 steps of harmonics. The objective was to confirm on each step, that the power factor increases, the total harmonic distortion decreases and to confirm on each step there is no electrical resonance.
  • Epsol engineers delivered analysis results in a comprehensible form (visualization, graphs, tables) to the customer, who approved what should be done. They designed, delivered and installed transformer, harmonic filter and additional equipment.
  • Epsol solution met the technical criteria required by the Mexican Grid Code. They achieved the desired level of harmonic, voltage and power quality.

What do they think about ETAP?

Opinions

Our main objective was to comply with all the technical requirements of the Mexican Grid Code. The first stage was the initial diagnosis. Then, we did all the studies using ETAP, and after all these detailed analyses, we could purchase all the equipment necessary to comply with the technical requirements.
By Carlos Moran Ramirez, Project Manager at EPSOL

We also used ETAP's harmonic module to meet the technical criteria and locate a harmonic filter in the best area. So, we conducted power flow analysis, short-circuit analysis, and protection coordination studies.
By Carlos Moran Ramirez, Project Manager at EPSOL



Videos

Harmonic Mitigation Project in Steel Plant

This presentation aims to explain the necessary steps to comply with national grid code standards; an exemplary case of a steel manufacturing plant with intensive use of induction furnaces and a THD that exceeded the Grid Code's limits. This presentation highlights compliance, analysis, engineering (electrical power system studies), and equipment designed to comply with the technical criteria and mitigation. ETAP was used to size a filter to mitigate harmonics and improve the power factor for 34.5 kV transformers for grid code compliance. 


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