The mining challenge
How much temporary energy is needed to move equipment weighing over 400,000 kilograms along a 4.5 km road in a maximum of 40 minutes? The question, which seems like one of those theoretical physics challenges that appear in the Enem (National High School Exam), became a reality for Tecnogera.
The company was hired to provide temporary energy for an excavator from one of the largest mining industries in the world. The gigantic challenge was only smaller than the company’s responsibility. Each minute of delay would mean a cost to the contractor of more than R$ 4,000. The excavator can produce 1,400 tons of iron ore per hour, so delays were not an option.
To overcome the challenge, Tecnogera and the mining company assembled a task force to keep all the variables of this journey under control. Learn a little more about the solutions used in this great success case in the temporary energy segment in Brazil.
The excavator
The contractor’s electric excavator was a CAT 6040, a hydraulic mining shovel excavator. Its engine is 1516 Kw (2,032 HP). The bucket capacity is 22 m³, which well illustrates the grandeur of the equipment.
The CAT 6040’s electrical system has a series installation of batteries. There are six 210 Ah, 12 V each. The excavator has 13 LED lights, 10 high-brightness LED work headlights, and 2 LED access headlights. The system voltage is 24 V.
The electric motor has a frequency of 50 Hz, an output of 1400 Kw, a nominal current of 156 A (at 6.6 kV), 1500 revolutions per minute, 350% initial current IN, and a voltage of 6.6 kV.
Tecnogera’s solutions
The company provided a mobile substation with 4 generators of 1,100 KVA, a 2,500 KVA transformer at 7.2 KV, in addition to protection cubicles and low and medium voltage cables.
Mobile substation
Mobile substations are the ideal solutions for large projects that need a constant and moving temporary energy supply. In the excavator project, the purpose of the mobile station was to meet the logistics, transformation, switching, control, protection, and supply supervision characteristics.
Tecnogera provided a complete mobile substation module to the mining company, but this solution can also be rented partially, containing only the line entry bay module, the transformation module, or the medium voltage module.
By renting a mobile substation from Tecnogera, the mining company was able to reduce downtime (the cost of stopping this excavator is R$ 250,000 per hour) and avoided costly and labor-intensive civil construction works.
1100 KVA generator
The four generators provided by Tecnogera have low fuel consumption, reducing operating costs. They have an integrated control system, including UPS, ATS, and a switching panel. They work with a voltage of 220 to 13,800 V, with a frequency of 50 Hz and a speed of 1,500 rpm.
The engine compression ratio is 13.5:1. The generator set accepts 100% of the nominal load in one step per NFPA 110 and meets the transient response of ISO 8528-5. The equipment has an air filter, radiator installed in the set, exhaust flange outlet, primary fuel filter with integrated water separator, secondary filter, and fuel priming pump, with power termination busbar.
Depending on the work to be performed, this type of generator can be supplied with exhaust silencers, anti-condensation heater, internal and permanent magnet excitation, UL-listed circuit breakers, and IEC compliance.
The operator can see, on the control panel and in real-time, the generator temperature and load sharing. All equipment used in the excavator’s movement was placed on trucks and interconnected by medium voltage cables.
The four 1,110 kVA generators handled the situation very well, as they have rubber anti-vibration mounts, spring-type vibration isolators, and IBC isolators. The 1110 KVA generator consumes about 305.4 liters of diesel per hour at 100% capacity; 232.6 liters/hour at 75%; and 167 liters/hour at 50% capacity.
The temperature emitted by the exhaust is 524º C. The exhaust system emits 259 m³ of gases per minute, thanks to the exhaust diameter of 203 mm. The system can withstand a pressure of 6.7 Kpa.
2,500 KVA transformer at 7.2 KV
The mobile transformer provided by Tecnogera for the excavator’s movement was a fundamental item for the success of the operation. These transformers have reduced weight and dimensions, which facilitates their movement and allows them to be placed on trucks.
The transformers have a three-phase silicon steel sheet core with low losses, insulated on both sides; low voltage winding in aluminum sheet and turns glued together by an insulating mat carrying adhesive resin.
They also have high voltage taps for system condition adjustments, connection made without load, and elastic pads for decoupling core and winding vibrations (reducing noise level).
The mixture of epoxy resin and quartz powder makes the mobile transformer maintenance-free, moisture-proof, and flame-resistant. The equipment also has bars for coil closure and PTC thermal sensors in the low voltage winding for temperature monitoring.
The transformer design is fully modular, meaning the equipment can be assembled and disassembled in the field. They operate at a frequency of 60 Hz, comply with the NBR 10295 noise standard, have an impedance of 5.75%, and a thermal class of 155º C. Each transformer weighs about 5,400 kilograms.
Final result
All the work was carried out by Tecnogera’s own operations team with the mining company’s professionals. The final balance was work carried out quickly, at low cost, with minimal fuel consumption, and unbeatable MW/hour cost-benefit.
Do you need temporary energy for the operation or construction of a mine? Contact a specialist.
