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Electrical Criteria
Published in Anthony J. Pansini, Transmission Line Reliability and Security, 2020
The usual transmission circuit consists of three energized conductors and a neutral or ground wire (Figure 2-3). Each conductor carries approximately one-third of the power flowing in the circuit (exactly one-third when evenly balanced). Each conductor is known as a phase; the circuit, therefore, is a three-phase circuit. Each phase is electrically 120 degrees apart from each other. The “disturbing” reactances associated with the position of each phase are also displaced 120 degrees from each other. Now, if each phase conductor can be relocated in its position relative to the other two for one-third of the circuit length, for the entire circuit, they will tend to cancel each other. The one-third length need not be all in one section of the line, but may consist of several transpositions totaling approximately one third. This is done with three phase length lines.
Types of Reactors and Their Design Parameters
Published in Robert E. Masterson, Nuclear Engineering Fundamentals, 2017
AC power having three phases is called three-phase power. It is generally preferable to other forms of AC power because it uses a less electrical conducting material to transmit the same electric power than equivalent single-phase or two-phase systems with an identical voltage. For this reason and others, it was first patented by Nikola Tesla in 1887 and 1888, and it subsequently came into widespread use in the early stages of the nineteenth century. In a three-pole generator, the poles are arranged in such a way that the individual currents from each pole vary sinusoidally at the same frequency but with a different phase. The peaks and troughs of their respective waveforms are intentionally offset by 1/3 of a cycle to provide three complementary alternating currents with a phase separation of 120°. The electrical power that is produced in this way is called three-phase power.
Three-Phase A.C. Circuits
Published in Christopher R Robertson, Further Electrical and Electronic Principles, 2010
As explained in Section 3.3, the distribution of 3-phase supplies is normally at a much higher line voltage than that required for many users. Hence, 3-phase transformers are used to step the voltage down to the appropriate value. A three-phase transformer is basically three single-phase transformers interconnected. The three primary windings may be connected either in star or delta, as can the three secondary windings. Similarly, the load connected to the transformer secondary windings may be connected in either configuration. One important point to bear in mind is that the transformation ratio (voltage or turns ratio) refers to the ratio between the primary phase to the secondary phase winding. The method of solution of this type of problem is illustrated in the following worked example.
A hybrid PV/utility powered irrigation water pumping system for rural agricultural areas
Published in Cogent Engineering, 2018
The proposed system is shown in Figure 2. In the proposed systems, each PV panel output is extracted through a MPPT DC/DC converter in order to get maximum power from PV panels. If the sun irradiation on one PV panel decreases, it does not affect other solar panels, because each PV panel has an independent MPPT controller, thus avoiding partial shading effects. Utility AC power is converted to DC by a three-phase rectifier. The outputs from DC/DC converter and three-phase rectifier are connected to common DC bus. This DC voltage is used to drive a three-phase voltage source inverter, which provides the power to the motor. The motor speed is regulated for a given flow rate using variable frequency inverter. This is an efficient way of driving motor according to desired flow rate. At daytime, solar power is utilized, and utility power is saved, thus saving electricity bill. So, an optimal way is developed and tested to drive motor, partially powered by solar panels, while taking remaining power from the utility.
Energy and material flow modelling of additive manufacturing processes
Published in Virtual and Physical Prototyping, 2018
Mazyar Yosofi, Olivier Kerbrat, Pascal Mognol
Electrical energy measurements were performed with a Norma 4000 power measurements three-phase power analyzer. Voltage probe was plugged into power socket in order to measure the voltage value in real time. The current clamp was plugged directly in the stripped supply power cable in power socket exit. This current sensor has an accuracy of 1% of reading ± 2 mA and a resolution of ± 1 mA. Hence, energy loss due to the electric transformer was taken into account for the electrical energy study. Instant power is calculated directly by the power metre by multiplying the rms-voltage, rms-current and power factor value. Then all the data were saved and processed to the power metre software on a computer. Figure 10 shows the electrical assembly diagram.
New three-port DC-AC inverter outputting a single-phase and a set of three-phase AC voltages
Published in International Journal of Electronics, 2018
Hurng-Liahng Jou, Jinn-Chang Wu, Kuen-Der Wu, Hong-Ren Shen
A DC-AC inverter converts the energy from a DC source to supply AC power to the load. In general, a DC-AC inverter can output either single-phase or three-phase AC voltage. However, both single-phase and three-phase loads may simultaneously exist in industrial applications and resident applications. In general, one three-phase DC-AC inverter and one single-phase DC-AC inverter are used to supply the three-phase load and single-phase load, respectively.