Life Cycle Energy Cost Assessment for Pump Units with Various Types of Line-Start Operating Motors Including Cable Losses

Abstract

<jats:p>The paper presents a comparative analysis of life-cycle energy consumption for three different types of 4 kW line-start motors used in a pump unit with throttling: the most widely used induction motor with IE3 efficiency class, line start permanent magnet synchronous motor with IE4 efficiency class and line start synchronous reluctance motor with IE4 efficiency class. The operating cycle for pump units with constant flow is considered for the above-mentioned types of motors taking into account not only the losses in the pump and motor, but also in the power supply cable. It is shown that the line start synchronous reluctance motor without magnets has the highest efficiency over the entire considered loading range. However, its power factor is lower than that of the synchronous motor with magnets and therefore it has more significant losses in power supply cable. Despite this disadvantage, the line-start reluctance motor is a good alternative to widespread induction motor since it allows saving of approximately 4000 euro more than the latter during the 20 years life cycle. It also provides similar savings in comparison to the permanent magnet synchronous motor, but unlike it, it does not have costly rare-earth materials in the rotor.</jats:p>

Feasibility Study of Direct-on-Line Energy-Efficient Motors in a Pumping Unit, Considering Reactive Power Compensation

“…In [11], the energy savings of the pump drive were estimated, taking into account the losses in the cable without taking into account the losses in the transformer. The article A number of studies are devoted to the analysis of energy savings in a pumping station due to an increase in the power factor of electric motors.…”

“…In [11], the energy savings of the pump drive were estimated, taking into account the losses in the cable without taking into account the losses in the transformer. The article compares annual energy savings and lifetime energy savings for induction motors (IM) of different efficiency classes, direct-on-line permanent magnet synchronous motor (DOL PMSM) and direct-on-line synchronous reluctance motor (DOL SynRM) (Figure 2).…”

“…DOL PMSM and DOL SynRM usually have a higher efficiency than IM due to the absence of electrical losses in the rotor from the first (fundamental) current harmonic when operating in a synchronous steady-state mode. In [11], it is shown that the power factor of the motor has a significant effect on the cable losses, but the losses in the transformer are not taken into account. However, transformer losses also significantly depend on the reactive component (power factor) of the load current.…”

“…This article, in contrast to [11,12], evaluates the energy savings when using static capacitors for reactive power compensation of various types of motors (IM of energy efficiency classes IE2 and IE3, DOL PMSM, DOL SynRM) in a pumping application. The energy savings when using motors of 3.7 kW, 60 Hz, four poles of various types in a pumping station and their payback period are assessed.…”

A Study on the Rotor Design of Line Start Synchronous Reluctance Motor for IE4 Efficiency and Improving Power Factor

“…A reactive power of an electrical motor depends on the power factor. If the reactive power is increased by the low power factor, the copper loss in stator winding increases under the same output power and input voltage condition because of the current increases [20]. This increased copper loss decreases the efficiency of the electrical motor.…”