Challenges

• Because of the mine's expansion, the topology of the electrical system should be updated and made accessible to enable control. The upgraded electrical system has to be reliable and efficient to keep the drilling process as continuous as possible.
• The design company should conduct studies on expanding the power demand by >100% from 8 MW to 20 MW. Calculations should include the addition of the new substation 138/13.8 kV.
• How can excessive voltage drops be corrected when the pump motors start? Large motors, 1250 HP, were used in the pumping station, which generated stability problems for the motors and other equipment in the electrical network. Consultants should also solve problems with low power factor.
• Ensuring the correct coordination of protective devices around the electrical network was crucial. The client wanted to use a very efficient and reliable electrical system.
• Finding the right tool to make an electrical network specification and build single-line diagrams in the computer system. The copper mine uses different voltage levels to ensure copper ore mining. The customer uses specific machines, sourced from multiple suppliers.
• The consulting office should consider many variations of electrical equipment and different protection methods. According to the standards, the office should provide load flow studies, short circuit studies, motor starting deep studies with recommendations, and protective coordination studies.

Selected applications

The ETAP Digital Twin model integrates information about the electrical installation, and is the base for research, calculations and recommendations.

StarZ™ protection and coordination software for transmission and distribution systems was used widely to ensure line and equipment protection settings.

Main Customer Benefits

• Modeling and validating an electrical network with all equipment and settings in One ETAP Digital Twin model, starting from the transmission high voltage (138 kV), distribution level (13,8 kV), and application levels (4160 or 480 volts). Engineers designed over 1,000 nodes in the model.
• Electro Integra engineers created several scenarios for the operation and the power supply to run electrical studies on 70 equivalent points. They validated a model using an actual and a new required field measurement without stopping production.
• Performed load flow studies, which showed which scenarios provoke voltage drops more than 5% and why the power factor is significantly low (70%) in certain places of the system. The client made and implemented recommendations.
• The Short Circuit Studies were provided by analyzing 3-phase, L-G, L-L-G, and L-L faults. All existing and new electrical equipment was taken into account, and all equipment was compliant.
• Engineers conducted Dynamic Motor Starting analysis to solve a crucial problem with the start of large motors in pumping stations. They designed and implemented recommendations to stabilize the system.
• To analyze the protective coordination, about five hundred "time current curves" were developed from 138 kV down to 480 volts to analyze the relay settings for the entire electrical system. Electro Integra delivered the relay settings to the client. The ETAP Auto-Evaluation tool and Sequence and Operation tool were used to verify relay settings against industry standards.
• The copper mine electrical system became reliable, stable, efficient, and accountable.

Opinions

We used the ETAP Star Auto Evaluation tool to check our settings against the industry standard and the Sequence of Operation tool to verify proper coordination with the devices in case of specific faults in the system.
By Gilberto Luy, Technical Manager, Electro Integra SAC