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ABSTRACT: A Monte Carlo based approach to evaluate the transient recovery voltages (TRVs) induced across circuit breaker poles during clearing faults on transmission lines equipped with a superconducting fault current limiter is presented here. In this context, investigations have been conducted on a sample power system model taking into consideration the uncertainty of several factors associated with the practical operation of a power system. Risk indices that reflect the likelihood that the TRV induced across a circuit breaker poles as well as its rate of rise exceed their design values are also presented. The EMTP-RV (Electro Magnetic Transients Program) was used in the simulation studies.
IET Generation Transmission & Distribution 02/2011; · 1.20 Impact Factor
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ABSTRACT: This study presents a stochastic-based approach to evaluate the probabilistic transient stability indices of a power system incorporating wind farms (WFs). In this context, investigations have been conducted on a hypothetical test system representing a typical power system taking into consideration the uncertainties of the factors associated with the practical operation of a power system, namely fault type, fault location, fault impedance, fault clearing process, system parameters and operating conditions and high-speed reclosing process. The effects of the WF sizes and locations on the overall system stability have been investigated. Moreover, this study presents stochastic models for the wind turbine as well as the spring constant of the reduced two-mass shaft model of the wind generator. The time-domain simulations are obtained using the electro-magnetic transient programme.
IET Renewable Power Generation 08/2010; · 1.74 Impact Factor
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ABSTRACT: Reliability evaluation of multiterminal HVDC systems has received very little attention in the past. This paper presents reliability modeling and analysis of an HVDC transmission system incorporating a voltage-sourced converter (VSC) tapping station. The use of VSC tapping stations enables the supply of power along the route to areas with comparatively little consumption. In this paper, a comprehensive detailed reliability model is developed and then converted to a manageable and computationally efficient model. Using this equivalent reliability model, various reliability indices are calculated at the load point of the system and the impacts of the VSC tapping station on these indices are illustrated. Sensitivity analyses are conducted to investigate the impacts of the load level and the location of the tapping station on the reliability indices. The conducted studies are numerically applied on a typical HVDC system and thorough discussions are presented.
IEEE Transactions on Power Delivery 08/2010; · 1.35 Impact Factor
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ABSTRACT: This paper presents a probabilistic-based approach to evaluate transient stability of a wind farm. In this context, investigations have been conducted on a hypothetical system representing a typical wind farm taking into consideration the uncertainty of several factors associated with the practical operation of a power system. A risk index that reflects the likelihood that the wind farm encounters an instability problem is presented. The time domain simulations are obtained using the electromagnetic transient program (EMTP).
IEEE Transactions on Energy Conversion 10/2009; · 2.27 Impact Factor
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ABSTRACT: Utilization of unified power flow controllers (UPFCs) can be more beneficial in the restructured power systems due to their capabilities in increasing the transmission line capacities as well as shunt reactive compensation. So, these devices should be installed such that the most benefit can be gained. In this paper, the problem of optimal placement of UPFCs is solved using Mixed-Integer Non-Linear Programming (MINLP) method. Hence, the problem is completely formulated based on this method and is solved using available commercial solvers. The salient feature of this method is having potential to simultaneously determine the optimal location of multi UPFCs. Also, since a full AC Optimal Power Flow (AC-OPF) is fulfilled during this process, functional parameters of UPFCs and results of OPF are obtained finally. Some case studies are examined to illustrate the effectiveness of the proposed formulation.
Power & Energy Society General Meeting, 2009. PES '09. IEEE; 08/2009
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ABSTRACT: A novel and simple stochastic-based approach to determine the optimal sizing of multiple flexible AC transmission systems (FACTS) devices in a power system for steady-state voltage profile enhancement is presented. In this context, investigations have been conducted on a published test system taking into consideration the uncertainty of the system load and generator scheduling. Two FACTS schemes are considered, namely a thyristor controlled series capacitor (TCSC) and two static synchronous compensators (STATCOMs) and a unified power flow controller (UPFC) and a STATCOM. The TCSC and UPFC are employed in the system to adjust the natural power sharing of two different parallel transmission lines and therefore enable the maximum transmission capacity to be utilised. Risk indices to estimate the likelihood that the voltage magnitude at a certain bus falls below a desired value is also presented.
IET Generation Transmission & Distribution 05/2009; · 1.20 Impact Factor
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ABSTRACT: The cross-magnetizing phenomenon of saturated synchronous machines plays an important role in their analysis using the two-axis frame models. To determine the parameters representing this phenomenon by the finite element method (FEM), the analysis has to be performed for excitations in the direct, quadrature and intermediate axes of the synchronous machines. This paper presents some investigations of the effect of some of the factors which may affect the accuracy of the analysis. To verify the accuracy of the calculated cross-magnetizing parameters, a specially-designed synchronous machine that can be excited from both its direct and quadrature axes is used to measure these parameters experimentally. The results of these studies have shown that the calculated parameters representing the cross-magnetizing phenomenon using the finite element method are in a good agreement with the measured values.
Electrical Machines, 2008. ICEM 2008. 18th International Conference on; 10/2008
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ABSTRACT: Voltage sags, also known as dips, are important to industrial reliability. This paper presents a Monte Carlo based approach to evaluate the maximum voltage sag magnitudes as well as the voltage unbalance in transmission systems. In this context, investigations have been conducted on a system model taking into consideration the uncertainty in several factors associated with the practical operation of a power system. MATLAB is used in the simulation studies.
IEEE Transactions on Power Delivery 11/2005; · 1.35 Impact Factor
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ABSTRACT: This paper presents a new control method based on fuzzy logic technique to control a unified power flow controller (UPFC) installed in a single-machine infinite-bus power system. The objective of the fuzzy logic based UPFC controller is to damp power system oscillations. Phillips-Herffron model of a single-machine power system equipped with a UPFC is used to model the system. The fuzzy logic based UPFC controller is designed by selecting appropriate controller parameters based on the knowledge of the power system performance. Simple fuzzy logic controller using mamdani-type inference system is used. The effectiveness of the new controller is demonstrated through time-domain simulation studies. The results of these studies show that the designed controller has an excellent capability in damping power system oscillations
Electrical and Computer Engineering, 2005. Canadian Conference on; 06/2005
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ABSTRACT: This paper presents a new control method based on a genetic algorithm (GA) technique to control a unified power flow controller (UPFC) installed in a single-machine infinite-bus power system. The objective of the GA based UPFC controller is to damp power system oscillations. Phillips-Herffron model of a single-machine power system equipped with a UPFC is used to model the system. The paper shows the capability of the UPFC to enhance power system performance by controlling its power flow. The GA controller is added to give the UPFC more flexibility and to increase its capability to damp the power system oscillations.
Electrical and Computer Engineering, 2004. Canadian Conference on; 06/2004
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IEE Proceedings - Generation Transmission and Distribution 12/2003; 150(6):768- 768. · 0.48 Impact Factor
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ABSTRACT: Composite system reliability studies incorporating a six-phase transmission line are presented. Both load-point and system indices are used to examine the impact on the individual bus and overall system reliability of incorporating a six-phase transmission line. Comparative studies are conducted in order to investigate the impact of the location of a six-phase transmission line on the load-point and system reliability indices. The worth of employing the six-phase transmission line is expressed in terms of the reduction in the customer interruption cost. The results are illustrated using a small test system.
IEE Proceedings - Generation Transmission and Distribution 08/2003; · 0.48 Impact Factor
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ABSTRACT: Voltage sags, also known as dips, are important to industrial reliability. This paper presents a Monte Carlo based approach to evaluate the maximum voltage sag magnitudes as well as the voltage unbalance ratio in transmission systems. In this context, investigations have been conducted on a system model taking into consideration the uncertainty in several factors associated with the practical operation of a power system. MATLAB is used in the simulation studies.
Power Tech Conference Proceedings, 2003 IEEE Bologna; 07/2003
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ABSTRACT: Voltage sags, also known as dips, are important to industrial reliability. This paper presents a Monte Carlo based approach to evaluate the maximum voltage sag magnitudes in series capacitor compensated radial distribution systems. In this context, investigations have been conducted on a sample distribution system model taking into consideration the uncertainty of several factors associated with the practical operation of a power system. The Power System Blockset of MATLAB is used in the simulation studies.
IEEE Power Engineering Review 12/2002; 22(11):63-63.
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ABSTRACT: An approach to determining the reliability of a hybrid multiterminal HVDC subtransmission system is presented. The performance analysis of a multiterminal HVDC subtransmission system is divided into three main segments: the rectifiers, the inverters and the underground cable system. The reliability models associated with the three segments are developed and a reliability evaluation procedure is presented. Two sets of indices, namely the basic load point indices and the system performance indices, are calculated to measure the reliability of a system. The proposed technique is applied to a hypothetical multiterminal HVDC subtransmission scheme and the results are presented.
IEE Proceedings - Generation Transmission and Distribution 10/2002; · 0.48 Impact Factor
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ABSTRACT: This paper presents a Monte Carlo based approach to evaluate the maximum torsional torques induced in turbine-generator shafts during faults on a HVAC/DC power system. In this context, investigations have been conducted on a large turbine-generator model taking into consideration the uncertainty of various factors associated with the practical operation of a power system. The results of these investigations are presented in the form of probability distributions of the maximum torsional torques induced in the turbine-generator shaft sections. A risk index that reflects the likelihood that the torque induced in a turbine-generator shaft exceeds its design value is also presented. Moreover, the paper presents a method for calculating the expected life expenditure ratio and the expected lifetime of turbine-generator shafts.
IEEE Transactions on Power Systems 09/2002; · 2.68 Impact Factor
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ABSTRACT: This paper explores the impact of six-phase transmission line
faults and their subsequent fault clearing and reclosing on the
torsional torques induced in turbine-generator shafts. In this context,
investigations have been conducted on a large turbine-generator unit
connected to a sample power system. The paper presents also a comparison
between the torsional stresses induced in the turbine-generator shafts
during these events with their corresponding disturbances of a
three-phase transmission system. The results of these investigations are
presented in the form of typical time responses as well as parametric
studies. The EMTP is used for the simulation studies. The studies
conclude that six-phase transmission line faults generally induce
torsional torques in the turbine-generator shaft whose magnitudes are
relatively higher than those induced due to transmission line faults in
a three-phase system. This conclusion is true for both sustained faults
and faults followed by clearing and high-speed reclosing
operations
IEEE Transactions on Power Systems 06/2002; · 2.68 Impact Factor
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ABSTRACT: This paper explores the impact of six-phase transmission line faults and their subsequent fault clearing and reclosing on the torsional torques induced in turbine-generator shafts. In this context, investigations have been conducted on a large turbine-generator unit connected to a sample power system. The paper presents also a comparison between the torsional stresses induced in the turbine-generator shafts during these events with their corresponding disturbances of a three-phase transmission system. The results of these investigations are presented in the form of typical time responses as well as parametric studies. The EMTP is used for the simulation studies. The studies conclude that six-phase transmission line faults generally induce torsional torques in the turbine-generator shaft whose magnitudes are relatively higher than those induced due to transmission line faults in a three-phase system. This conclusion is true for both sustained faults and faults followed by clearing and high-speed reclosing operations.
IEEE Power Engineering Review 05/2002; 22(4):76-76.
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ABSTRACT: This paper presents an approach to perform AC/DC system reliability analysis in a composite system where a hybrid compensating scheme is employed in the AC link to adjust the transmission infeed impedance and, therefore, increase the transmission system capacity. The hybrid scheme consists of a static synchronous series compensator (SSSC) and a fixed capacitor. Reliability models associated with a bipolar DC link and the hybrid compensating scheme are developed. A wide range of indices is calculated at both the load point and system levels using a contingency enumeration technique. The capabilities of the technique and the models presented in the paper are illustrated using a small but typical AC/DC system.
Electrical and Computer Engineering, 2002. IEEE CCECE 2002. Canadian Conference on; 02/2002
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ABSTRACT: Voltage sags, also known as dips, are important to industrial reliability. This paper presents a Monte Carlo based approach to evaluate the maximum voltage sag magnitudes in series capacitor compensated radial distribution systems. In this context, investigations have been conducted on a sample distribution system model taking into consideration the uncertainty of several factors associated with the practical operation of a power system. The Power System Blockset of MATLAB is used in the simulation studies.
Power Engineering 2002 Large Engineering Systems Conference on, LESCOPE 02; 02/2002
