scholarly journals A new approach to three-phase asynchronous motor model for electric power system analysis

Author(s):  
Laura Collazo Solar ◽  
Angel A. Costa Montiel ◽  
Miriam Vilaragut Llanes ◽  
Vladimir Sousa Santos

In this paper, a new steady-state model of a three-phase asynchronous motor is proposed to be used in the studies of electrical power systems. The model allows for obtaining the response of the demand for active and reactive power as a function of voltage and frequency. The contribution of the model is the integration of the characteristics of the mechanical load that can drive motors, either constant or variable load. The model was evaluated on a 2500 kW and 6000 V motor, for the two types of mechanical load, in a wide range of voltage and frequency, as well as four load factors. As a result of the evaluation, it was possible to verify that, for the nominal frequency and voltage variation, the type of load does not influence the behavior of the powers and that the reactive power is very sensitive to the voltage variation. In the nominal voltage and frequency deviation scenario, it was found that the type of load influences the behavior of the active and reactive power, especially in the variable load. The results demonstrate the importance of considering the model proposed in the simulation software of electrical power systems.

2019 ◽  
Vol 11 (24) ◽  
pp. 7202 ◽  
Author(s):  
M. A. Graña-López ◽  
A. García-Diez ◽  
A. Filgueira-Vizoso ◽  
J. Chouza-Gestoso ◽  
A. Masdías-Bonome

Reactive power is an important parameter in electrical power systems since it affects the efficiency of the system because it is not useful energy. It decreases the power factor of the system and limits the ability of generators to deliver useful power. It is therefore necessary to understand and correctly measure the phenomenon of reactive energy in three-phase systems. In this paper, we analyze reactive power in linear and unbalanced three-phase systems using the Unified Theory of Electrical Power and the Institute of Electrical and Electronics Engineers Standard 1459-2010 (IEEE Std. 1459-2010) to obtain expressions for reactive power in balanced and unbalanced systems and noting that there are terms that exist only for unbalanced systems. Analysis of the measurements carried out led us to identify the existence of two components of reactive power—that due to reactive elements, and that caused by unbalances in the system. Knowing the causes that generate reactive power, it is possible to act more effectively on the problem and therefore achieve a more sustainable generation of electric power and a lower environmental impact.


2011 ◽  
Vol 383-390 ◽  
pp. 6861-6867
Author(s):  
Xu Sheng Wu ◽  
Wei Gao

Double-winding AC-DC Generator are being widely used in self-contained electrical power systems for their obvious virtues. On their stator, two separate windings are distributed, one three-phase winding delivers AC power and the other twelve-phase winding, termed DC windings, are connected to the bridge rectifier to supply DC power. Unlike ordinary three-phase machines, there are four layers winding in each stator slot of the Double-winding AC-DC Generator and the total gap magnetic potential produced by the twelve-phase winding is more complex than 3-phase machines. By analyzing the leakage magnetic flux and the magnetic potential, relevant formulas are derived to calculate the leakage reactance of the machines. All the stator leakage reactance of a realistic Double-winding AC-DC Generator was calculated through the methods presented and the simulation of a sudden shortcut test of the machine was carried out with the parameters calculated. The simulation and test results agree quite well, and show that the formulas presented are correct.


Author(s):  
K. Nithiyananthan ◽  
Simson Samson Raja ◽  
R Sundar ◽  
A Amudha

<p><em>The main objective of this research work is to develop a simple power systems steady state stability estimator in LabView for three phase power system network. LabVIEW based power systems stability estimator has been chosen as the main platform because it is a user friendly and easy to apply in power systems. This research work is intended to simultaneously acclimate the power system engineers with the utilization of LabVIEW with electrical power systems. This proposed work will discuss about the configuration and the improvement of the intelligent instructional VI (virtual instrument) modules in power systems for power systems stability solutions. In the proposed model power systems stability has been carried out and model has been developed such that it can accommodate the latest versions of power systems stability algorithms.</em></p>


Author(s):  
Gustavo Vinicius Duarte Barbosa ◽  
José Ronaldo Tavares Santos

Electrical power systems are susceptible to faults caused, for example, by storm, pollution, vandalism, lightning, salt spray, etc. The unscheduled interruption in the supply of electricity to consumers, whether industrial, residential, or commercial, entails severe fines for the transmission utility and/or electricity distributor, imposed by the regulatory agency. Thus, the EPS must have a well-dimensioned protection system, capable of identifying the fault, which is characterized by a single-phase, two-phase, three-phase short circuit, among others, and interrupt the missing section in the minimum time so that the effects of this lack are as small as possible for the SEP, especially with regard to its integrity and operational security.


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