ANALYSIS OF THREE-PHASE CASCADED H-BRIDGE MULTILEVEL CONVERTER FOR LARGE SCALE SOLAR POWER SYSTEM APPLICATIONS

Author(s):  
Jigneshkumar Pramodbhai Desai ◽  
Vijay Hiralal Makwana

AbstractOut-of-step protection of one or a group of synchronous generators is unreliable in a power system which has significant renewable power penetration. In this work, an innovative out-of-step protection algorithm using wavelet transform and deep learning is presented to protect synchronous generators and transmission lines. The specific patterns are generated from both stable and unstable power swing, and three-phase fault using the wavelet transform technique. Data containing 27,008 continuous samples of 48 different features is used to train a two-layer feed-forward network. The proposed algorithm gives an automatic, setting free and highly accurate classification for the three-phase fault, stable power swing, and unstable power swing through pattern recognition within a half cycle. The proposed algorithm uses the Kundur 2-area system and a 29-bus electric network for testing under different swing center locations and levels of renewable power penetration. Hardware-in-the-loop (HIL) tests show the hardware compatibility of the developed out-of-step algorithm. The proposed algorithm is also compared with recently reported algorithms. The comparison and test results on different large-scale systems show that the proposed algorithm is simple, fast, accurate, and HIL tested, and not affected by changes in power system parameters.


2019 ◽  
Vol 11 (3) ◽  
pp. 309-331
Author(s):  
Assist. Prof. Dr. Inaam I. ALI ◽  
Mohanad Sh. Tarad AL-AASAM

Preliminary studies on Iraqi power system show a significant increase in the short circuit level at some of the grid substations and some power stations. This increasing results from the growth of the power generation and transmission systems in size and complexity. Islanding or splitting is dividing the power system into several islands inorder to reduce short circuit levels and avoiding blackouts. The main islanding problem is determining the location of proper splitting points and load balance and satisfaction of transmission capacity constraints for each islands.This paper mainly introduces new proposed splitting strategies of large-scale power systems by using (PSS™E version 30.3 PACKAGE PROGRAME), such that, make re-interconnection of 400KV super high voltage substation based on three-phase load flow to be minimum flow at splitting point and infeed fault current details method to control short circuit levels in Iraq power system without islanding the power system into isolated islands. Controlled islanding or splitting scheme is frequently considered as the final solution to avoid blackouts of power system.Simulation IEEE-25 bus and Iraqi power system used as the test systems for this method. Furthermore, simulation results show significant effectiveness on reducing short circuit levels with same time give stable splitting islands with same frequency for preventing the system blackouts.


Author(s):  
Xia Zhou ◽  
Yichen Li ◽  
Ping Chang ◽  
Jianfeng Dai ◽  
Yi Tang

Background: With respect to the problem of wind power and photovoltaic (PV) grid-connected accommodation, a power system optimization dispatching method is proposed that introduces a concentrating solar power (CSP) station to promote wind power and PV accommodation, considering the dispatch-ability of the thermal storage system (TSS) and the accommodation capacity of the electric heating device (EHD) in the CSP station. Methods: The method analyzes an internal simplified model of a CSP station and a short-time-scale identification method of wind and PV power ramping events based on a CSP-Wind-PV system structure. Furthermore, the operating characteristics and constraints of various units are considered with the goal of the lowest comprehensive system cost to establish a CSP-Wind-PV optimization model for dispatching power system. Results: The method is simulated and verified on the IEEE-RTS24 node system by using the MATLAB optimization toolbox. Conclusion: The results demonstrate that the participation of a CSP station can decrease the number of power ramping events and reduce the curtailment of wind and PV power while ensuring the economical operation of the power system.


Author(s):  
M.H.T.T. Thilekha ◽  
K.M.H.D. Siriwardana ◽  
N.R.D. Siebel ◽  
D.A.D. Waslathanthri ◽  
N.W.A. Lidula ◽  
...  

2013 ◽  
Vol 860-863 ◽  
pp. 309-313
Author(s):  
Xiao Yan Bian ◽  
Li Ning Yang ◽  
Xin Xin Huang ◽  
Yang Fu

Large scale wind farm output variation always deteriorates the system stability. To study this problem, this paper builds the model of power system with the integration of large-scale wind farm based on BPA. The simulation results show that large oscillations of voltage and rotor angle of system will happen, when three-phase short circuit fault occurs on the main line for transmitting wind power. With wind farm output decreasing, the transient stability and small-signal stability of power system will be improved.


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