scholarly journals Design and Expansion Planning of Parallel Inverter Based AC Microgrids - An Approach for Improved Stability Margins

2020 ◽  
Author(s):  
Ayesha Firdaus ◽  
Marta Molinas
Keyword(s):  
Time Domain ◽  
System Stability ◽  
Value Analysis ◽  
Stability Margins ◽  
Expansion Planning ◽  
Eigen Value ◽  
Sufficient Stability ◽  
Improved Stability ◽  
The Impact ◽  
Modelling Approach

<div>This paper presents an application of impedancebased modelling approach to identify suitable locations for design<br></div>and expansion planning of an inverter based autonomous AC microgrid. The objective is to find out ideal location for placement of additional components which can include new inverter-based sources, microgrid damping controller, etc., ensuring sufficient stability margins. These objectives are achieved by first identifying the weakest and the strongest nodes in the system with respect to the system stability and then observing the effects of choosing various nodes for design and expansion on overall system stability. The weakest and the strongest nodes are identified<br>using the impedance based stability analysis of the microgrid by dividing the system in various possible partition points while the impact of choosing different locations on stability is analyzed by eigen value analysis as well as time-domain MATLAB/Simulink simulations and experimental results. <div> <br><b>This paper has been submitted to JESTPE on 25-04-2020 and rejected on 29-08-2020.</b></div>

scholarly journals Design and Expansion Planning of Parallel Inverter Based AC Microgrids - An Approach for Improved Stability Margins

2020 ◽  
Author(s):  
Ayesha Firdaus ◽  
Marta Molinas
Keyword(s):  
Time Domain ◽  
System Stability ◽  
Value Analysis ◽  
Stability Margins ◽  
Expansion Planning ◽  
Eigen Value ◽  
Sufficient Stability ◽  
Improved Stability ◽  
The Impact ◽  
Modelling Approach

<div>This paper presents an application of impedancebased modelling approach to identify suitable locations for design<br></div>and expansion planning of an inverter based autonomous AC microgrid. The objective is to find out ideal location for placement of additional components which can include new inverter-based sources, microgrid damping controller, etc., ensuring sufficient stability margins. These objectives are achieved by first identifying the weakest and the strongest nodes in the system with respect to the system stability and then observing the effects of choosing various nodes for design and expansion on overall system stability. The weakest and the strongest nodes are identified<br>using the impedance based stability analysis of the microgrid by dividing the system in various possible partition points while the impact of choosing different locations on stability is analyzed by eigen value analysis as well as time-domain MATLAB/Simulink simulations and experimental results. <div> <br><b>This paper has been submitted to JESTPE on 25-04-2020 and rejected on 29-08-2020.</b></div>

scholarly journals Electric Vehicles in Jordan: Challenges and Limitations

2021 ◽  
Vol 13 (6) ◽  
pp. 3199
Author(s):  
Laith Shalalfeh ◽  
Ashraf AlShalalfeh ◽  
Khaled Alkaradsheh ◽  
Mahmoud Alhamarneh ◽  
Ahmad Bashaireh
Keyword(s):  
Electric Vehicles ◽  
Distribution System ◽  
Distribution Systems ◽  
Environmental Benefits ◽  
System Stability ◽  
Loading Conditions ◽  
Stability Margins ◽  
High Penetration ◽  
Node Distribution ◽  
The Impact

An increasing number of electric vehicles (EVs) are replacing gasoline vehicles in the automobile market due to the economic and environmental benefits. The high penetration of EVs is one of the main challenges in the future smart grid. As a result of EV charging, an excessive overloading is expected in different elements of the power system, especially at the distribution level. In this paper, we evaluate the impact of EVs on the distribution system under three loading conditions (light, intermediate, and full). For each case, we estimate the maximum number of EVs that can be charged simultaneously before reaching different system limitations, including the undervoltage, overcurrent, and transformer capacity limit. Finally, we use the 19-node distribution system to study these limitations under different loading conditions. The 19-node system is one of the typical distribution systems in Jordan. Our work estimates the upper limit of the possible EV penetration before reaching the system stability margins.

Carbon Brush Wear of Radar Tachometer Identification Technology Based on Eigen Value Analysis in Time Domain

2014 ◽  
Vol 602-605 ◽  
pp. 1883-1886 ◽  
Author(s):  
Hui Feng Liu ◽  
Yong Ming Nie ◽  
Kai Chen ◽  
Fuan Sun ◽  
Hao Zhu
Keyword(s):  
Time Domain ◽  
High Reliability ◽  
Processing Method ◽  
Dimensional Parameter ◽  
Value Analysis ◽  
Detection Technology ◽  
Eigen Value ◽  
New Type ◽  
The Time Domain ◽  
Output Information

A new type of tachometer carbon brush wear detection technology is proposed based on data acquisition and signal processing technology, the key of which is that the tachometer carbon brush output information is acquired and processed, moreover, the real time conditions of the carbon brush wear are detected and analyzed based on the time domain Eigen value analysis method. During the data processing process, the results of the dimensional parameter processing method are compared with the results of the dimensionless parameter processing method at the same time. Then, we find that the detecting precision is greatly promoted and measurement probability is guaranteed by reasonable threshold selection. Experimental results indicate that the technology proposed here has high stability, high reliability, and high detecting probability, which has great practical value and deserves being extended widely.

Time-Domain Simulation of Power System Frequency Fluctuations Caused by Intermittent Wind Power

2013 ◽  
Vol 441 ◽  
pp. 304-311
Author(s):  
Hao Ming Liu ◽  
Fang Fang Zhu ◽  
Ke Lin Yang
Keyword(s):  
Power System ◽  
Wind Power ◽  
Wind Turbines ◽  
Time Domain ◽  
Electric Power System ◽  
System Stability ◽  
Equivalent Transformation ◽  
Time Domain Simulation ◽  
System Frequency ◽  
The Impact

Wind power is uncertain. When the proportion of wind power capacity is large, the impact of the randomness of the output power on the grid frequency is more significant. Aiming at system stability influence after integrating a high capacity of wind turbines, this paper introduces the dynamic simulation model for electric power system with wind power, and makes an equivalent transformation processing for the wind turbine and generator. By using improved Euler method, this paper analyzes the impact of system frequency through time-domain simulation when disturbance occurs at wind farm side. Simulation results show that when wind speed changes, the established model and algorithm can effectively simulate the dynamic response of the frequency, and also these results can provide a reference for the frequency stability when wind turbines integrate into power system.

scholarly journals Classification of standing and sitting phases based on in-socket piezoelectric sensors in a transfemoral amputee

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tawfik Yahya ◽  
Nur Azah Hamzaid ◽  
Sadeeq Ali ◽  
Farahiyah Jasni ◽  
Hanie Nadia Shasmin
Keyword(s):  
Time Domain ◽  
Classification Accuracy ◽  
Sensory System ◽  
Metabolic Energy ◽  
Support Vector ◽  
Data Set ◽  
Transfemoral Amputee ◽  
Sit To Stand ◽  
Optimal Classifier ◽  
The Impact

AbstractA transfemoral prosthesis is required to assist amputees to perform the activity of daily living (ADL). The passive prosthesis has some drawbacks such as utilization of high metabolic energy. In contrast, the active prosthesis consumes less metabolic energy and offers better performance. However, the recent active prosthesis uses surface electromyography as its sensory system which has weak signals with microvolt-level intensity and requires a lot of computation to extract features. This paper focuses on recognizing different phases of sitting and standing of a transfemoral amputee using in-socket piezoelectric-based sensors. 15 piezoelectric film sensors were embedded in the inner socket wall adjacent to the most active regions of the agonist and antagonist knee extensor and flexor muscles, i. e. region with the highest level of muscle contractions of the quadriceps and hamstring. A male transfemoral amputee wore the instrumented socket and was instructed to perform several sitting and standing phases using an armless chair. Data was collected from the 15 embedded sensors and went through signal conditioning circuits. The overlapping analysis window technique was used to segment the data using different window lengths. Fifteen time-domain and frequency-domain features were extracted and new feature sets were obtained based on the feature performance. Eight of the common pattern recognition multiclass classifiers were evaluated and compared. Regression analysis was used to investigate the impact of the number of features and the window lengths on the classifiers’ accuracies, and Analysis of Variance (ANOVA) was used to test significant differences in the classifiers’ performances. The classification accuracy was calculated using k-fold cross-validation method, and 20% of the data set was held out for testing the optimal classifier. The results showed that the feature set (FS-5) consisting of the root mean square (RMS) and the number of peaks (NP) achieved the highest classification accuracy in five classifiers. Support vector machine (SVM) with cubic kernel proved to be the optimal classifier, and it achieved a classification accuracy of 98.33 % using the test data set. Obtaining high classification accuracy using only two time-domain features would significantly reduce the processing time of controlling a prosthesis and eliminate substantial delay. The proposed in-socket sensors used to detect sit-to-stand and stand-to-sit movements could be further integrated with an active knee joint actuation system to produce powered assistance during energy-demanding activities such as sit-to-stand and stair climbing. In future, the system could also be used to accurately predict the intended movement based on their residual limb’s muscle and mechanical behaviour as detected by the in-socket sensory system.

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