scholarly journals A Fast Method to Compute the Dynamic Response of Induction Motor Loads Considering the Negative-Sequence Components in Stability Studies

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1802
Author(s):  
Xiaoming Mao ◽  
Junxian Chen

This paper deals with the modeling and simulation of induction motor loads in power system stability studies considering the influence of the negative-sequence components. A practical method for computing the dynamic behavior of an induction motor under asymmetric faults is proposed and implemented in MATLAB. The accuracy of the proposed method is verified through classical electromagnetic transient simulations using the PSCAD/EMTDC software package. Compared with the existing traditional transient stability simulations, the method increases a little computational burden yet achieves much better simulation accuracy under asymmetric faults.

2018 ◽  
Vol 58 ◽  
pp. 03016 ◽  
Author(s):  
I.V Naumov ◽  
N.V. Savina ◽  
M.V. Shevchenko

One of the main operation modes that characterizes power quality in distribution networks is asymmetry of three-phase voltage system. Operation of an induction motor (IM) with disturbed voltage symmetry in the supply network can not be considered as a rated one. The system of voltages applied to the stator winding of IM under these conditions contains positive- and negative-sequence components. This worsens the performance characteristics of IM essentially. In order to balance the 0.38 kV network operation and enhance the efficiency of the three-phase electric motor operation it is suggested to use a special balancing unit (BU) that minimizes the negative-sequence components of current and voltage. The operation modes of the obtained system “supply source – induction motor – balancing unit” are simulated within the MATLAB software package of applied programs, which allows one to assess the impact of low quality of power on the operating characteristics of the electric motor and the efficiency of the balancing unit to increase the “durability” of the motor under the asymmetrical power consumption.


2016 ◽  
Vol 36 (1) ◽  
pp. 213-226
Author(s):  
PO Oluseyi ◽  
TS Adelaja ◽  
TO Akinbulire

The poor investment in the network expansion programme has led to high level of grid fragility experienced in the power transmission system in Nigeria. Thus, any little disturbance often results in cascaded outage which is very hazardous to the power system equipment and operation. In order to overcome or ameliorate the influence of this challenge, the network engineers have to devise methodologies based on the dynamic stability analysis. This motivates the development of power system transient stability model presented herein. The developed model is thus applied to a specimen of the Nigeria’s transmission power system, i.e. the Ikeja-West Sub-network. This choice is influenced by the fact that the Ikeja-West sub-network is the hub of power transmission arteries in Nigeria. Thus the Electrical Transient and Analysis Program (ETAP) software is deployed to operate on the ensuing model. This then leads to generating a series of results that demonstrates the different scenarios in respect of the system stability studies. The method adopted is quite appealing and promising as a tool in sustaining system stability and security during slight disturbance to the network during operation.http://dx.doi.org/10.4314/njt.v36i1.26


2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Gayatridevi Rajamany ◽  
Sekar Srinivasan ◽  
Krishnan Rajamany ◽  
Ramesh K. Natarajan

The intention of fault detection is to detect the fault at the beginning stage and shut off the machine immediately to avoid motor failure due to the large fault current. In this work, an online fault diagnosis of stator interturn fault of a three-phase induction motor based on the concept of symmetrical components is presented. A mathematical model of an induction motor with turn fault is developed to interpret machine performance under fault. A Simulink model of a three-phase induction motor with stator interturn fault is created for extraction of sequence components of current and voltage. The negative sequence current can provide a decisive and rapid monitoring technique to detect stator interturn short circuit fault of the induction motor. The per unit change in negative sequence current with positive sequence current is the main fault indicator which is imported to neural network architecture. The output of the feedforward backpropagation neural network classifies the short circuit fault level of stator winding.


2003 ◽  
Vol 40 (1) ◽  
pp. 66-71
Author(s):  
Y. G. Paithankar ◽  
S. R. Bhide

In this paper a method to filter or segregate sequence components, using minimal hardware is presented. The method does not involve phase shifts other than that of 90 degrees. Thus it can be implemented using very simple hardware or if implemented in software will need considerably less amount of processing. The method consists in first separating the zero sequence component. Then the zero sequence component is subtracted from the input signal to get a signal which is sum of positive and negative sequence components. Further it is pointed out that difference between positive and negative sequence components is easily found from the difference of the phase quantities. Thus the sum and difference of positive and negative sequence components are available, from which individual positive and negative sequence components can be easily separated by simple addition and subtraction operations.


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