SVC device optimal location for voltage stability enhancement based on a combined particle swarm optimization-continuation power flow technique

The increased power system loading combined with the worldwide power industry deregulation requires more reliable and efficient control of the power flow and network stability. Flexible AC transmission systems (FACTS) devices give new opportunities for controlling power and enhancing the usable capacity of the existing transmission lines. This paper presents a combined application of the particle swarm optimization (PSO) and the continuation power flow (CPF) technique to determine the optimal placement of static var compensator (SVC) in order to achieve the static voltage stability margin. The PSO objective function to be maximized is the loading factor to modify the load powers. In this scope, two SVC constraints are considered: the reference voltage in the first case and the total reactance and SVC reactive power in the second case. To test the performance of the proposed method, several simulations were performed on IEEE 30-Bus test systems. The results obtained show the effectiveness of the proposed method to find the optimal placement of the static var compensator and the improvement of the voltage stability

GWO-super-twisting integral sliding mode control of 60 KW PV system based on interleaved boost converter

The energy provided by the PV system is strongly influenced by climatic conditions such as solar radiation and cell temperature. A suitable DC /DC converter and a robust control strategy combined with the maximum power point tracking (MPPT) algorithm are required to harness the maximum power of the panel. This paper proposes a super-twisting integral sliding mode control (ST-ISMC) for four legs interleaved boost converter (FLIBC) as an interface to the MPPT algorithm for a 60 KW PV system. The FLIBC has been used to overcome the drawbacks of the conventional boost converter (CBC). The ST-ISMC is proposed to maintain the PV voltage track the reference provided by the MPPT algorithm and ensure the equal sharing of input current between legs. The controller gains of the proposed ST-ISMC have been calculated using the grey wolf optimization algorithm for better performance. The simulation results prove the excellent performance of the proposed controller over the conventional controller

SVC device optimal location for voltage stability enhancement based on a combined particle swarm optimization-continuation power flow technique

The increased power system loading combined with the worldwide power industry deregulation requires more reliable and efficient control of the power flow and network stability. Flexible AC transmission systems (FACTS) devices give new opportunities for controlling power and enhancing the usable capacity of the existing transmission lines. This paper presents a combined application of the particle swarm optimization (PSO) and the continuation power flow (CPF) technique to determine the optimal placement of static var compensator (SVC) in order to achieve the static voltage stability margin. The PSO objective function to be maximized is the loading factor to modify the load powers. In this scope, two SVC constraints are considered: the reference voltage in the first case and the total reactance and SVC reactive power in the second case. To test the performance of the proposed method, several simulations were performed on IEEE 30-Bus test systems. The results obtained show the effectiveness of the proposed method to find the optimal placement of the static var compensator and the improvement of the voltage stability

Commande numérique industrielle des convertisseurs à thyristors d'une machine synchrone autopilotée

One of the important points of this study, which has been carried out in cooperation with EDF-CEGELEC-CRAN, is the complete realization of an industrial digital control of a self-controlled synchronous machine. This realization is based 0!l a given operation requirements specification especially for firing angle accuracy and variable-frequency following. In the first part of the thesis, phenomena related to the imperfections of power supply network are studied in a certain depth, especially the extraction of the fundamental of a noisy variable-frequency network. This is a specific research on the synchronizing problem. In the second part, we discuss digital firing circuits for thyristors and gate pulse production algorithms. We will give a description and a comparaison of several existing firing algorithms (reference crossing, time delayed, incremental) and then, propose a firing algorithm said hybrid algorithm. Finally, a complete study is made on firing control (from operation requirements specification to its hardware and software realization) of thyristor bridges for a self-controlled synchronous machine. Note that the rapidity of process, the complexity of the interaction between different functions make us, during the realizing procedure, to' follow the design method MAREL (Méthode de conception d'Applications temps Réel pour la commande de processus ELectromécaniques : design method for real time applications in electromechanical process control) developed in CRANUn des points importants de cette étude, qui s'inscrit dans le cadre d'une collaboration de recherche EDF-CEGELEC-CRAN, est la réalisation complète d'une commande numérique industrielle d'une machine synchrone autopilotée sur la base d'un cahier des charges présentant des contraintes en précision pour les angles de retard à l'amorçage et en dynamique de suivi fréquentiel. Une première partie de cette thèse contribue d'une manière importante à l'étude des phénomènes liés aux imperfections du réseau électrique d'alimentation, en particulier à l'extraction de la composante fondamentale d'un réseau perturbé à fréquences variables. Ceci représente une recherche spécifique sur le problème de synchronisation. Une seconde partie s'intéresse aux allumeurs numériques et aux méthodes de génération des impulsions de gâchettes. Une description et une étude comparative de plusieurs allumeurs déjà existants (allumeur à coïncidence, à retard, incrémental) est faite, ensuite, un allumeur (allumeur multi-stratégies) est proposé. Une dernière partie présente, enfin, l'étude complète (du cahier des charges à la réalisation pratique) de la commande de portes d'une machine synchrone autopilotée. Par ailleurs, la rapidité des processus, la complexité des interactions entre les différentes fonctions ont conduit à concevoir cette commande en se basant sur le formalisme de la méthode MAREL (Méthode de conception d'Applications temps Réel pour la commande de processus Électromécaniques) développée au CRA

Sliding mode controller for four leg shunt active power filter to eliminating zero sequence current, compensating harmonics and reactive power with fixed switching frequency

In this paper, the four leg inverter controlled by the three dimensional space vector modulation (3D SVM) is used as the shunt active power filter (SAPF) for compensating the three phase four wire electrical network, by using the four leg inverter with 3D SVM advantages to eliminated zero sequence current, fixed switching frequency of inverter switches, and reduced switching losses. This four leg inverter is employed as shunt active power filter to minimizing harmonic currents, reducing magnitude of neutral wire current, eliminating zero sequence current caused by nonlinear single phase loads and compensating reactive power, and a nonlinear sliding mode control technique (SMC) is proposed for harmonic currents and DC bus voltage control to improve the performances of the three phase four wire four leg shunt active power filter based on Synchronous Reference Frame (SRF) theory in the dq0 axes, and to decoupling the four leg SAPF mathematical model

Commande numerique industrielle des convertisseurs a thyristors d'une machine synchrone autopilotee

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 80765 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc