Voltage stability assessment for distrbuted generation in islanded microgrid system

The increasing energy demands are stressing the generation and transmission capabilities of the power system. Distributed generation (DG), which generally located in distribution systems, has the ability to meet some of the growing energy demands. However, unplanned application of individual distributed generators might cause other technical problems. The microgrid concept has the potential to solve major problems arising from large penetration of DG in distribution systems. A microgrid is not a forceful system when it is compared to a power system. This project proposes a simulation approach to study voltage stability index (VSI) and voltage stability analysis in microgrid system for the improvement of the dynamic voltage stability in a microgrid in case of the dynamic voltage insufficiency. A model of IEEE-14 Bus System has been presented as a case study of an islanded microgird system. This project also presented line voltage stability index analysis which accurately performs voltage stability analysis at each transmission line and precisely predicts voltage collapse on power systems. A formula to calculate VSI has been derived and applied on two cases on the system. To show the effectiveness of the proposed voltage stability analysis method, this approach is implemented in a microgrid test system (14-bus, 20 lines) in PSAT which is a MATLAB toolbox environment. The test system has four diesel DGs and a wind turbine connected with eleven constant loads. The dynamic simulation of the test system is carried out for various types of disturbances. Islanded mode of operation is considered in this study. Fast Voltage Stability Index (FVSI) and voltage stability analysis have been successfully implemented and analysed

Voltage Stability Analysis of Grid-Connected Wind Farms with FACTS: Static and Dynamic Analysis

Recently, analysis of some major blackouts and failures of power system shows that voltage instability problem has been one of the main reasons of these disturbances and networks collapse. In this paper, a systematic approach to voltage stability analysis using various techniques for the IEEE 14-bus case study, is presented. Static analysis is used to analyze the voltage stability of the system under study, whilst the dynamic analysis is used to evaluate the performance of compensators. The static techniques used are Power Flow, V–P curve analysis, and Q–V modal analysis. In this study, Flexible Alternating Current Transmission system (FACTS) devices- namely, Static Synchronous Compensators (STATCOMs) and Static Var Compensators (SVCs) - are used as reactive power compensators, taking into account maintaining the violated voltage magnitudes of the weak buses within the acceptable limits defined in ANSI C84.1. Simulation results validate that both the STATCOMs and the SVCs can be effectively used to enhance the static voltage stability and increasing network loadability margin. Additionally, based on the dynamic analysis results, it has been shown that STATCOMs have superior performance, in dynamic voltage stability enhancement, compared to SVCs

Voltage stability analysis of load buses in electric power system using adaptive neuro-fuzzy inference system (anfis) and probabilistic neural network (pnn)

This paper presents the application of neural networks for analysing voltage stability of load buses in electric power system. Voltage stability margin (VSM) and load power margin (LPM) are used as the indicators for analysing voltage stability. The neural networks used in this research are divided into two types. The first type is using the neural network to predict the values of VSM and LPM. Multilayer perceptron back propagation (MLPBP) neural network and adaptive neuro-fuzzy inference system (ANFIS) will be used. The second type is to classify the values of VSM and LPM using the probabilistic neural network (PNN). The IEEE 30-bus system has been chosen as the reference electrical power system. All of the neural network-based models used in this research is developed using MATLAB

Improving the Voltage Stability and Performance of FACTS Controller in Transmission Line Network

Conventionally Shunt Compensation is used to increase the transfer capability of a transmission line. By using FACT'S controllers one can manage the variables such as voltage magnitude and phase angle at selected bus and line impedance. Objective of this paper is to recover dynamic voltage control and consequently increasing system load ability for 50 Hz Frequency. Now a day, five well known FACT'S devices generally used for this purpose. These FACT'S devices are (SVC) Static VAR Compensator, (TCSC) Thyristor Controlled Series Capacitor, (STATCOM) Static Synchronous Compensator, and (UPFC) Unified Power Flow Controller and (SSSC) Static Synchronous Series Compensator. The voltage drop occurs when a system is loaded beyond its highest load ability point, then many investigation methods have been projected for the study of this difficulty. Mainly of These techniques are based on the classification of system stability. These stable points are typically referred as points of voltage collapse. This paper present modeling and simulation of STATCOM & SVC in Matlab Simulink for dynamic voltage performance of transmission line network

Voltage instability analysis on the Sabah grid system: a case study my

With the development of the power system, voltage stability has become a major concern in planning and operating electric power system. The blackout problem has been associated with not only transient stability but also voltage stability. Voltage Instability in the Sabah Grid System has resulted in several major system failures. The recent major system failure due to the voltage instability happened on the 30 April 2012, where Sabah Grid System experienced a total collapse. This highlighted the need for detailed voltage stability studies to improve the voltage control especially during trough load period and to prevent the reoccurrence of similar incident. This report performs the analysis on the Voltage Instability study case of the 30 th th April 2012 event and the performance of the Sabah Grid System using the PSS/E simulator involving the load flow analysis, steady-state contingency analysis, Short circuit Studies and Transient Stability studies. This project presented several operating strategies to mitigate the voltage problems including the implementation of the new 66kV radial configuration to improve the voltage stability especially in the 66kV network which is the most critical part of Sabah Grid System. The additional of new 66kV and 132kV shunt reactor to be installed and several recommendations are proposed to maintain substation voltage to be within the specified limits. The analysis shows that the voltage in the 66kV network and the 132kV network has a significant improvement after the fast corrective action and the new 66kV radial configuration have been implemented