Efficient Transmission System
The oil and gas sector has the most challenging power requirements due to the motors that drive essential equipment, including pumps, compressors, or drilling rigs. The efficiency of the motor determines how much energy is consumed by the entire package. Three-phase motors supply a stable output torque and deliver more useful power to the driven object through their relatively efficient transmission. Single-phase motors cannot do this. These advantages allow them to maintain good performance under high loads and during extended operation times.
For three-phase motors, the efficiency is usually from 85% to 95%; for single-phase motors, it can be at most 60%–70%. For instance, a typical 100 kW compressor driven by a three-phase motor could save about 15%–20% of energy annually compared to a single-phase motor. If the equipment runs 6,000 hours per year, the electrical savings of the three-phase motor on this equipment would be 900,000 kWh. This saves on energy costs as well as reduces carbon emissions, which are in accordance with energy-saving and emission reduction realized by the industry.
Variable Frequency Control for Energy Savings
Equipment in the oil and gas industry is usually motorized and runs at the same speed, while the actual load required changes a lot, leading to inefficient operation. If a variable-frequency drive (VFD) is used for motor control with a three-phase motor, the speed of the motor can be automatically adjusted in response to load requirements while still delivering an appropriate amount of power output, thereby avoiding wasting energy.
Variable frequency control technology can save 20%–50% of electricity. One such case is that an oil company originally used standard fixed-speed motors for its pumps and consumed nearly 8 million kWh per year. By changing all of its motors to three-phase motors with variable frequency drives, the company managed to lower its energy consumption to 4.8 million kWh and saved more than 2 million yuan in electricity costs.
Lower Maintenance Costs
The severe operating conditions of the oil and gas industry demand that equipment run continuously; any maintenance or downtime disrupts production schedules and incurs significant costs. When it comes to harsh-environment applications like these, three-phase motors provide a solution with simple architecture, stable running conditions, and low maintenance costs.
Traditional single-phase motors are prone to problems like overheating and vibration, which often result in wear leading to maintenance. On the other hand, three-phase motors are generally built with fewer moving parts, and power is delivered evenly over all phases, ensuring smooth operation and lower failure rates. Industry data has shown that the MTBF of three-phase motors is 30%–40% higher than that of single-phase motors, and maintenance costs can be reduced by 25%.
Reduced Heat Loss
During operation, motors generate heat; in high peak load and long-duration applications, that heat buildup has a significant effect on energy efficiency. Too much heat means that motors wear away more rapidly and may eventually fail, adding to the cooling systems’ burden.
Compared to single-phase motors that consume more energy and produce more heat, three-phase motors have less loss due to their evenly distributed current across three phases. The National Renewable Energy Laboratory has confirmed that the temperature rise in three-phase motors is 15% to 20% less than in single-phase motors based on experimental data. Essentially, this allows these systems to run more efficiently for longer and prevents energy waste from the heat that is produced.
Power Factor Correction
Power factor is a very important parameter of energy efficiency in electrical systems. The oil and gas industry uses high-power equipment ranging from drilling rigs to oil pumps, requiring a large amount of reactive power, which burdens the grid and decreases energy efficiency. Power factor correction capability of three-phase motors can be achieved by reducing the consumption of reactive power and can increase the overall system power factor.
