- Gebze Institute Of Technology, Electronics Engineering, Faculty Memberadd
- Engineering, Power System, Power Quality, Renewable Energy, Electrical machine, Power electronics, Distributed power generation, Power Systems, and 19 moreSmart Grid, Microgrid, Plug In Hybrid Electric Vehicles, Fuel Cell Vehicles, Hydrogen Economy, Electronics Engineering, Wind Energy, Power Generation, Transmission and Distribution, Power Quality Signal Analysis Using DSP, Earthing Systems, Earthing Design of Transmisison and Distribution System, Dc railway systems, Earthing, Electrical Power System Modelling and and Load Flow Analysis, Fault current calculation, Reactive Power Compensation, Stray current, and Electrical Engineeringedit
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Energy storage systems (ESSs) and demand-side management (DSM) strategies have significant potential in providing flexibility for renewable-based distribution networks. Therefore, combining ESSs and DSM strategies with renewable energy... more
Energy storage systems (ESSs) and demand-side management (DSM) strategies have significant potential in providing flexibility for renewable-based distribution networks. Therefore, combining ESSs and DSM strategies with renewable energy sources (RESs) to solve economic, operational, environmental, and power-related political issues has received special attention from power system planners around the world. In this regard, developed countries, which are pioneers in renewable technologies, have proposed various supportive policies and practices for the widespread use of ESSs and DSM strategies in the context of distribution networks. Hence, this paper performs a comprehensive review of the most recent actions taken to build the infrastructure necessary to achieve 100% renewable energy. On this basis, this paper firstly surveys the necessity of using ESSs and DSM strategies in renewable-based distribution networks. Then, the existing policies and incentive programs implemented in differ...
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The topology of a distribution network can be represented by a bus injection to branch current (BIBC) matrix. It has been introduced and used for load flow analysis of distribution networks. In this paper, a method for BIBC matrix... more
The topology of a distribution network can be represented by a bus injection to branch current (BIBC) matrix. It has been introduced and used for load flow analysis of distribution networks. In this paper, a method for BIBC matrix modification is developed to use in applications which require a topology change representation. Proposed method that reflects the changes in configuration in the system BIBC matrix is implemented in distribution network reconfiguration problem. With providing potential solutions for network operational and planning requirements such as necessitate changes in configurations to transfer the loads to a different substation, ease the loading of equipment, conduct planned maintenance and reduce network losses during the normal operation with renewables, storage and other uprising technologies, reconfiguration may also be useful for emergencies, accidents, attacks and weather-related disasters. The BIBC modification process provides the knowledge of possible sw...
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The synchronous generators (SGs) supplying non-linear loads have harmonically distorted terminal voltages. Hence, these distorted terminal voltages adversely affect the performance parameters of the supplied loads such as the power... more
The synchronous generators (SGs) supplying non-linear loads have harmonically distorted terminal voltages. Hence, these distorted terminal voltages adversely affect the performance parameters of the supplied loads such as the power factor, current distortion, losses, and efficiency. To mitigate the harmonic voltages and currents, passive and active filters are generally employed. However, passive filters cause resonance problems, while active filters can cause high costs. On the other hand, in several recent studies to reduce the SG’s terminal voltage harmonic distortion, which depends on the constructional design under the no-loading condition, the conventional DC excitation current has been modulated with AC harmonic components. These field current modulation methods have high computational complexity, and require extra hardware for their implementation. In the present paper, firstly, for the reduction of the terminal voltage harmonic distortion of the SG under non-linear loading ...
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In power systems, the practice of overcurrent protection is more economical and common than the distance protection practice. In addition, overcurrent protection is used in the majority of distribution networks. This makes it necessary to... more
In power systems, the practice of overcurrent protection is more economical and common than the distance protection practice. In addition, overcurrent protection is used in the majority of distribution networks. This makes it necessary to design the coordination of overcurrent relays used in distribution networks in the most appropriate way. Otherwise, the relays cannot work as desired during the fault. In order for the coordination between the overcurrent relays to be effective and selective, the relay setting parameters must be adjusted depending on the network. With the expansion of distribution networks, it has become difficult to calculate or update the relay settings. For this reason, overcurrent relay coordination is designed as an optimization problem with a high number of constraints. At the point of solving the optimization problem, many meta-heuristic algorithms have been developed. In this study, the Greywolf Optimization Algorithm (GWO) for the IEEE 8 Bus test network has been successfully applied and comprehensive performance analysis has been carried out.
Güç sistemlerinde aşırı akım koruma pratiği, mesafe koruma pratiğinden daha ekonomik ve yaygındır. Ayrıca dağıtım şebekelerinin büyük bir çoğunluğunda aşırı akım koruma kullanılmaktadır. Bu durum, dağıtım şebekelerinde kullanılan aşırı akım rölelerin koordinasyonun en uygun şekilde tasarlanmasını gerekli kılmaktadır. Aksi halde sistemde gerçekleşen bir arıza sırasında röleler istenildiği gibi çalışamaz. Aşırı akım röleleri arasında koordinasyonun etkili ve seçici olabilmesi için röle ayar parametrelerinin şebekeye uygun ayarlanması gerekmektedir. Dağıtım şebekelerinin genişlemesi ile birlikte röle ayarlarının hesaplanması veya güncellenmesi zorlaşmıştır. Bu nedenle aşırı akım röle koordinasyonu yüksek sayıda kısıt içeren optimizasyon problemi şeklinde kurgulanmaktadır. Optimizasyon problemini çözümü noktasında ise peç çok meta-sezgisel algoritmalar geliştirilmiştir. Bu çalışmada IEEE 8 Baralı test şebekesi için Bozkurt Optimizasyon Algoritması (BOA) başarılı bir şekilde uygulanmış ve kapsamlı performans analizi gerçekleştirilmiştir.
Güç sistemlerinde aşırı akım koruma pratiği, mesafe koruma pratiğinden daha ekonomik ve yaygındır. Ayrıca dağıtım şebekelerinin büyük bir çoğunluğunda aşırı akım koruma kullanılmaktadır. Bu durum, dağıtım şebekelerinde kullanılan aşırı akım rölelerin koordinasyonun en uygun şekilde tasarlanmasını gerekli kılmaktadır. Aksi halde sistemde gerçekleşen bir arıza sırasında röleler istenildiği gibi çalışamaz. Aşırı akım röleleri arasında koordinasyonun etkili ve seçici olabilmesi için röle ayar parametrelerinin şebekeye uygun ayarlanması gerekmektedir. Dağıtım şebekelerinin genişlemesi ile birlikte röle ayarlarının hesaplanması veya güncellenmesi zorlaşmıştır. Bu nedenle aşırı akım röle koordinasyonu yüksek sayıda kısıt içeren optimizasyon problemi şeklinde kurgulanmaktadır. Optimizasyon problemini çözümü noktasında ise peç çok meta-sezgisel algoritmalar geliştirilmiştir. Bu çalışmada IEEE 8 Baralı test şebekesi için Bozkurt Optimizasyon Algoritması (BOA) başarılı bir şekilde uygulanmış ve kapsamlı performans analizi gerçekleştirilmiştir.
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Increasing power demand and limited sources give rise to researches for sustainable energy supplies. Renewable energy sources like solar cell, wind turbine, fuel cell, and hydro turbine are the common technologies for sustainable,... more
Increasing power demand and limited sources give rise to researches for sustainable energy supplies. Renewable energy sources like solar cell, wind turbine, fuel cell, and hydro turbine are the common technologies for sustainable, exhaustless and nonpolluting energy. In recent years, great interests have been directed to integration of embedded resources to the grid. Embedded resources have place in electric power networks as distributed generation units. DG-units have many advantages as providing loss reduction, improving voltage profile, and increasing reliability of system. Using renewable sources as a DG-unit has many parameters to assess. In this paper DG-units which have been considered as renewable resources are integrated at optimal place with optimal size into distribution system. This optimization process is performed with Artificial Bee Colony (ABC) algorithm. ABC algorithm is a meta-heuristic approach inspired by the intelligent foraging behavior of honey bee swarms. ABC algorithm has two parameters to estimate. Therefore updating them for effective values to get higher success is easier than other meta-heuristic methods. ABC algorithm is used in this study to determine DG-unit’s optimal size and place in order to minimize total system power loss. 33 and 69 bus radial test systems and 229 bus real distribution system are used in order to show the performance of ABC algorithm in solving nonlinear optimization problems. Results are compared with grid search method and success of ABC algorithm is approved.
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Recent developments in computer technology and numerical techniques now enable full dynamic studies to be carried for fault current calculations. Existing international standards, however, are still based on hand-calculation approaches.... more
Recent developments in computer technology and numerical techniques now enable full dynamic studies to be carried for fault current calculations. Existing international standards, however, are still based on hand-calculation approaches. Generally, fault current calculations are required to determine fault current interruption requirements and, in the main, consider three-phase balanced faults. However, fault current calculations are also required to establish the extent and structural design of earthing systems, and in this case ...
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In power system distributed generation has rapidly increased due to many technical, economical and environment aspects. Distribution network operators face with challenges lately with integration of distributed generation. The aim to... more
In power system distributed generation has rapidly increased due to many technical, economical and environment aspects. Distribution network operators face with challenges lately with integration of distributed generation. The aim to increase distributed generation and make distribution system less attached to central generation release many problems in planning and operating a network. To keep distribution system safe and reliable the effects of distributed generation is to be investigated. Lately, optimal allocation problems give place to high penetration problems. In order to guide distribution network operators for high penetration level of distributed generation in the existing systems with less investment needs new approaches are required. An analytical approach is introduced in this paper to maximize penetration level of distributed generation without increasing total power loss of system. 33-bus and 69-bus test distribution systems and a 229-bus real network are used to implement method and results are presented.
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For non-sinusoidal single-phase systems, the classical apparent power has been divided into various components using different techniques. These power resolutions generally aim at to provide a tool for the accurate determination of the... more
For non-sinusoidal single-phase systems, the classical apparent power has been divided into various components using different techniques. These power resolutions generally aim at to provide a tool for the accurate determination of the maximum power factor achievable with a passive compensator and to measure the load.s nonlinearity degree. This paper presents a current decomposition-based methodology that can be employed for computationally efficient implementation of the widely recognized non-sinusoidal power resolutions. The proposed measurement method and the original expressions of the power resolutions are comparatively evaluated by considering their computational complexity. The results show that the proposed method has a significant advantage in terms of computational efficiency for the simultaneous measurements of the powers when compared with the original expressions. Finally, in this paper, a PC-based power meter is developed using the proposed measurement method via the L...
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ABSTRACT Uluslararası Elektroteknik Komisyonu (IEC) tarafından yayınlanan Güç Transformatörleri ile ilgili IEC 60076 Standart serisine 2011 yılında IEC 60076-16 "Rüzgâr Türbini Uygulamaları için Transformatörler" bölümü... more
ABSTRACT Uluslararası Elektroteknik Komisyonu (IEC) tarafından yayınlanan Güç Transformatörleri ile ilgili IEC 60076 Standart serisine 2011 yılında IEC 60076-16 "Rüzgâr Türbini Uygulamaları için Transformatörler" bölümü eklenmiş ve bu bölümde rüzgâr türbini uygulamalarında kullanılacak transformatörlerin uyması gereken şartlar detaylı bir şekilde tanımlanmıştır. Projelendirme sırasında büyük önemi olan transformatör rezonans frekansının belirlenebilmesi için uygun test sistemi de yine bu kısımda detaylandırılmıştır. Bu çalışmada detayları standartta verilen elektriksel rezonans frekansı test devresi kullanılarak ölçümler yapılmış, testler ve verilerin işlenmesi sırasında karşılaşılan güçlükler vurgulanmıştır. Standartta verilen yöntemle hesaplanan rezonans frekansı değerinin, Frekans Cevap Analizi (Frequency Responce Analysis, FRA) testi ile elde edilen sonucu doğruladığı görülmüştür.
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ABSTRACT In this paper, some exemplary cases are presented to show the effect of voltage total harmonic distortion (THDV) and its spectrum on the harmonic loss factors (F HL and F HL-STR) of the six-pulse rectifiers accompanied with a... more
ABSTRACT In this paper, some exemplary cases are presented to show the effect of voltage total harmonic distortion (THDV) and its spectrum on the harmonic loss factors (F HL and F HL-STR) of the six-pulse rectifiers accompanied with a constant power dc load and a battery. Accordingly, the winding losses and maximum loading capability of a transformer supplying both non-linear load types are investigated for sinusoidal and non-sinusoidal bus voltage conditions. The obtained numerical results clearly shows that the current harmonics of the considered non-linear load types are highly dependent on the THDV level and spectrum of the supply voltage, thus, the voltage harmonic profile should be considered in the design stage of the transformers, which are under influence of particular to supply them.
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ABSTRACT This paper proposes a model of the induction generator for the phase-domain power flow analysis of fixed speed wind turbine generating systems connected to balanced or unbalanced three-phase distribution systems. The proposed... more
ABSTRACT This paper proposes a model of the induction generator for the phase-domain power flow analysis of fixed speed wind turbine generating systems connected to balanced or unbalanced three-phase distribution systems. The proposed model is established by using a modified bi-quadratic equation, which is generally used for the calculation of node voltages in the power flow analysis of distribution systems. The main advantage of the proposed model is that it does not require slip information. Thus, it has computational efficiency when compared with the slip calculation based phase-domain induction generator model. In addition, for several unbalanced voltage cases, the numerical results of the proposed model, slip calculation based phase-domain model and time-domain d-q model are comparatively evaluated to show the validity of the proposed one.
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Renewable source based energy generation become a solution in today's power system to provide unlimited clean energy as well as reducing carbon emission. Distributed generators are significant applicant for a network that will help to... more
Renewable source based energy generation become a solution in today's power system to provide unlimited clean energy as well as reducing carbon emission. Distributed generators are significant applicant for a network that will help to supply the ascending energy demand with clean energy. As distribution network operators intend to increase distributed generation penetration they need to investigate and find solution how to operate the system reliable and safely considering the negative effects of them. It has significant importance to be aware of the penetration capacity of system for future planning and investments. In this paper, a beginning of a study is presented to show the effects of distributed generator penetration level in a distribution system. An analytical approach is introduced regarding total power loss of a distributed generator penetrated system and a heuristic method is used to make further analysis. Changes in power loss depending on distributed generators size can be obtained with both methods. The results will give an insight to distribution network operators in their planning and operation as well as future investments.
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More than 80% of all system faults occur on the power systems are single phase to ground type faults and large majority of these faults are of a transient nature. For ensuring reliability of electricity transmission system, Single Pole... more
More than 80% of all system faults occur on the power systems are single phase to ground type faults and large majority of these faults are of a transient nature. For ensuring reliability of electricity transmission system, Single Pole Autoreclosers play an important role. However, conventional Single Pole Autoreclosers has no intelligent decision making tool for identification of fault type. In this study, effectiveness of the Adaline based fault type identification method is evaluated via simulation.
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Renewable source based energy generation become a solution in today's power system to provide unlimited clean energy as well as reducing carbon emission. Distributed generators are significant applicant for a network that will help to... more
Renewable source based energy generation become a solution in today's power system to provide unlimited clean energy as well as reducing carbon emission. Distributed generators are significant applicant for a network that will help to supply the ascending energy demand with clean energy. As distribution network operators intend to increase distributed generation penetration they need to investigate and find solution how to operate the system reliable and safely considering the negative effects of them. It has significant importance to be aware of the penetration capacity of system for future planning and investments. In this paper, a beginning of a study is presented to show the effects of distributed generator penetration level in a distribution system. An analytical approach is introduced regarding total power loss of a distributed generator penetrated system and a heuristic method is used to make further analysis. Changes in power loss depending on distributed generators size...
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It is seen from the study [1] that there is a need for a power resolution, which can be utilized for the direct provision of the optimum compensation capacitor's power and give some useful information on the detection of the harmonic... more
It is seen from the study [1] that there is a need for a power resolution, which can be utilized for the direct provision of the optimum compensation capacitor's power and give some useful information on the detection of the harmonic producing loads, in the literature. Accordingly, for nosinusoidal and unbalanced systems, a power resolution, which achieves these goals, is proposed in this paper.
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It is seen from the preliminary work [1] of this paper that in the literature there is a need for a power resolution, which can be utilized for (i) the direct provision of the optimum compensation capacitor’s power and (ii) obtaining... more
It is seen from the preliminary work [1] of this paper that in the literature there is a need for a power resolution, which can be utilized for (i) the direct provision of the optimum compensation capacitor’s power and (ii) obtaining meaningful information on the detection of the harmonic producing loads. This paper proposed a power resolution that can be used to achieve both goals under nosinusoidal and unbalanced conditions in the smart power grids. First goal is important for cost effective unity power factor compensation including a basic capacitor and an active compensator. The second goal is required for the practical detection of harmonic producing loads by using the demand meters, which are employed to measure the powers for the energy billing of the consumers. The proposed power resolution is based on the separation of load current into orthogonal components as active, reactive, scattered conductance, scattered susceptance, unbalanced conductance and unbalanced susceptance ...
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Summary: in recent years, the detailed modelling of power electronic devices and their behaviours on various system conditions are a great concern of the power industries and customers. one of the widely proliferated such devices is the... more
Summary: in recent years, the detailed modelling of power electronic devices and their behaviours on various system conditions are a great concern of the power industries and customers. one of the widely proliferated such devices is the triac controlled ac choppers. although these types of devices have important application areas, their poor power factor is the main obstacle for the large scale implementation in power systems. This paper presents an analysis on the behaviour of a single phase load composed with triac controlled ac chopper during the reactive power compensation with a basic capacitor in nonsinusoidal voltage case. The results of these analysis show that the distortion of voltage improves power factor, which is contradicting with previous findings, for the high conduction angles of triac controlled ac chopper. in addition, it is observed that the performance of power factor improvement with a basic capacitor is noticeably affected by the phase angles of voltage harmon...
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In this paper, the widely recognised apparent power definitions, which are Arithmetic, Vector, IEEE standard, DIN standard apparent power definitions and the apparent power definition of Mayordomo and Usaola, are rigorously reviewed, and... more
In this paper, the widely recognised apparent power definitions, which are Arithmetic, Vector, IEEE standard, DIN standard apparent power definitions and the apparent power definition of Mayordomo and Usaola, are rigorously reviewed, and their abilities on the measurement of the system’s power transfer efficiency are analysed by using a specially derived apparent power, which is calculated in terms of the total line losses of the system with and without the reactive power compensation. In the analyses, two major compensation strategies, namely the minimum line loss (MLL) and sinusoidal and balanced current (SBC) compensation strategies, are considered to determine the total line loss of the system with the compensation. Therefore, in a representative nonsinusoidal and unbalanced test system, the results are simulated by taking into account unbalance among the resistances of neutral and phase lines. The simulated results show that under nonsinusoidal and unbalanced conditions, the un...
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In recent studies on the power concept, Poynting Vector is employed to derive Instantaneous Power and an important tool for investigation of the physical meaning of Apparent Power in nonsinusoidal conditions. Hitherto Instantaneous Power... more
In recent studies on the power concept, Poynting Vector is employed to derive Instantaneous Power and an important tool for investigation of the physical meaning of Apparent Power in nonsinusoidal conditions. Hitherto Instantaneous Power was described as a postulate in the literature and not exactly derived for general conditions. In this study, Poynting Vector is used for the exact derivation of power in the electrical circuits and explanation of the physical meaning of Apparent Power components in nonsinusoidal conditions for more general conditions.
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This paper describes a new approach for modelling of automatic voltage regulator in the forward/backward sweep-based algorithms for unbalanced radial distribution systems. The automatic voltage regulators (AVRs) are included into the... more
This paper describes a new approach for modelling of automatic voltage regulator in the forward/backward sweep-based algorithms for unbalanced radial distribution systems. The automatic voltage regulators (AVRs) are included into the sweep based methods and tested by using two distribution test systems. From the studies, it can be concluded that all results are in agreement, the proposed approach is valid and reliable, and the performance of the algorithms is less affected from the inclusion of regulator modelling.
This paper describes a software package whose purpose is to provide a tool to be used for defining the optimal size and placement of Distributed Generation and shunt capacitors in distribution networks with three optimization algorithms... more
This paper describes a software package whose purpose is to provide a tool to be used for defining the optimal size and placement of Distributed Generation and shunt capacitors in distribution networks with three optimization algorithms for power system studies. The package also achieves to identify the closeness of the each bus and the critical bus which is the most sensitive to the voltage collapse in radial distribution networks. It uses the graphical user interface capabilities of MATLAB and called Voltage Stability & Optimization (VS&OP) Package. It is available at http://www.gyte.edu.tr/Dosya/102/power/ and can freely be downloaded. The paper is organized in two parts. This is the first part of the paper that deals with Optimization module.
Changes in distribution system such as integration of low-carbon technologies and sudden changes between generation and demand, force grid to quickly respond the changes for keeping the system reliable and sustainable. In grid operation... more
Changes in distribution system such as integration of low-carbon technologies and sudden changes between generation and demand, force grid to quickly respond the changes for keeping the system reliable and sustainable. In grid operation reconfiguration is one of the tools that modifies radial structure of distribution feeder from time to time in order to improve operating conditions of system. Generally heuristic methods are used to change open-close status of switches to reconfigure the system. However, analyzing the network with analytical methods give opportunity to observe the effects of all system components from mathematical expressions. This paper gives a beginning of an analytical approach for reconfiguration problem. Analytical expressions for distributed load profile is developed to decide switch location to separate feeders and proposed method is implemented to a simple 12-bus system.
In this article, a reluctance-based model is developed for time-efficient analysis of shell type single-phase power transformers under the direct current (dc) bias conditions. Unlike other reluctance-based transformer models in the... more
In this article, a reluctance-based model is developed for time-efficient analysis of shell type single-phase power transformers under the direct current (dc) bias conditions. Unlike other reluctance-based transformer models in the literature, the developed one considers frequency dependent nature of the winding resistances. This is important especially for accurate determination of losses and maximum loading capability (MLC) of the transformers under dc bias and non-sinusoidal conditions. In addition to that, by using the developed model, three different MLC determination approaches, which are based on the rated primary side current, rated total loss and rated primary winding loss, are examined for dc bias conditions. These novel examination results clearly point out that among three approaches the rated primary winding loss-based one should be preferred for the safe operation of the transformers in the systems with dc bias.
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View all references, 44. Hatziargyriou, ND, Karakatsanis, TS and Papadopoulos, M. 1993. Probabilistic load flow in distribution systems containing dispersed wind power generation. IEEE Trans. Power Syst. , 8(1): 159–165. [CrossRef], [Web... more
View all references, 44. Hatziargyriou, ND, Karakatsanis, TS and Papadopoulos, M. 1993. Probabilistic load flow in distribution systems containing dispersed wind power generation. IEEE Trans. Power Syst. , 8(1): 159–165. [CrossRef], [Web of Science ®] View all references, 55. Coath, G. and Al-Dabbagh, M. 2005. Effect of steady-state wind turbine generator models on power flow convergence and voltage stability limit. Australasian Universities Power Engineering Conference (AUPEC 2005). 25-28 September 2005 , Australia. ... View all references, 66. Coughlan, Y., ...