Analysis of grid connected induction generators driven by hydro/wind turbines under realistic system constraints

Results of an investigation dealing with the behaviour of grid-connected induction generators (GCIGs) driven by typical prime movers such as mini-hydro/wind turbines are presented. Certain practical operational problems of such systems are identified. Analytical techniques are developed to study the behavior of such systems. The system consists of the induction generator (IG) feeding a 11 kV grid through a step-up transformer and a transmission line. Terminal capacitors to compensate for the lagging VAr are included in the study. Computer simulation was carried out to predict the system performance at the given input power from the turbine. Effects of variations in grid voltage, frequency, input power, and terminal capacitance on the machine and system performance are studied. An analysis of self-excitation conditions on disconnection of supply was carried out. The behavior of a 220 kW hydel system and 55/11 kW and 22 kW wind driven system corresponding to actual field conditions is discussed

Erfarenheter av yrkesinriktad rehabilitering. Lantbruksföretagarnas berättelser om yrkesinriktad rehabilitering ur ett identitetsperspektiv.

Den här avhandlingen handlar om lantbruksföretagare som genomgått yrkesinriktad rehabilitering. De har blivit tvungna att omskola sig till ett nytt yrke efter att de har insjuknat i yrkessjukdom eller skadat sig i ett olycksfall. Avhandlingens syfte är att öka förståelsen av hurdana erfarenheter lantbruksföretagare har av sin rehabiliteringsprocess. Rehabiliteringsätgärden, i det här fallet omskolningen, baserar sig på lagen om rehabilitering som ersätts enligt lagen om olycksfallsförsäkring. Materialet i avhandlingen bestär av 21 livsberättelser skrivna av de rehabiliterade som genomgått omskolningen. Undersökningen är därför narrativ tili sin natur. Analysen gjorde jag med hjälp av innehållsanalys och med hjälp av att tematisera innehållet i berättelserna. Tematiseringen var en central metod genom hela analysen och fungerade som ett redskap för att beskriva och tolka materialet. Rehabiliteringsprocessen frän början till slut ser jag även som ett identitetsprojekt och en process dar de rehabiliterade har varit tvungna att göra biografiskt arbete. Jag baserar min processindelning pä Corbin's och Strauss' (1988) defmition om att biografiskt arbete vid en krissituation i livet eller livsförändring innefattar fyra processer; kontextualisering, accepterande, äteruppbyggande av identiteten och omarbetning av biografin. Jag definierar insjuknandet eller skadan som en gemensam livsförändring för de rehabiliterade. De rehabiliterade har varit tvungna att konstruera en ny eller delvis en ny biografisk identitet som stämmer överens med de nya aktuella livsförhällandena, med framtida livsförhällanden och med tidigare erfarenheter. För största delen av de rehabiliterade hade rehabiliteringsprocessen varit en positiv erfarenhet och de hade lyckats med det biografiska arbetet för att återuppbygga identiteten och omarbeta biografin. Det var bara några av de rehabiliterade som ansåg att de inte hade haft någon nytta av rehabiliteringen. Det var personer som inte hade fått arbete efter omskolningen. Positiva studieerfarenheter och att man lyckas skaffa sig en utbildning i vuxen älder har för många varit faktorer som har gett dem bättre självkänsla och ökat deras självförtroende och dessutom skapat resurser för att kunna gå vidare i livet.

Promoting the European Union : Attitudinal stance adjectives in three genres of EU communication to the public

Målet för Pro Gradu-avhandlingen är att undersöka hur Europeiska unionen (EU) marknadsförs genom användningen av värderande adjektiv i tre genrer av skriftlig kommunikation från EU till medlemsstaternas medborgare. Undersökningen är inriktad på tre forskningsfrågor: hur marknadsföringen av EU syns i användningen av värderande adjektiv i de tre genrerna, vilka de centrala skillnaderna mellan de tre genrerna är gällande användningen av värderande adjektiv, samt på vilket sätt texterna uppfyller sitt kommunikativa syfte, nämligen att informera allmänheten om EU:s verksamhet och marknadsföra EU som en giltig och handlingskraftig union. Den teoretiska ramen för undersökningen grundar sig på genreanalys, kommunikationsteori och teorier om hur författarens värdering (stance) syns i texter. Skillnaden mellan genre, texttyp och register diskuteras, och teoridelen redogör även för begreppet diskurssamfund, dvs. den grupp personer som i ett yrkesmässigt eller institutionellt sammanhang producerar och använder sig av en genre enligt dess kommunikativa konventioner. Materialet behandlas även utgående från Egon Werlichs indelning av texttyper i deskriptiva, narrativa, expositära, argumentativa och instruktiva texter. Materialet består av tre delar som representerar var sin genre: informationsbroschyrer, pressmeddelanden och den Allmänna rapporten om Europeiska unionens verksamhet, som utges av EU varje år. Storleken på varje del av materialet varierar mellan 20 000 - 30 000 ord. Materialet har valts på basis av de teman texterna behandlar, och kriterierna för urvalet är bl.a. att texterna behandlar ämnen som har anknytning till medborgarnas vardag, att de är riktade till allmänheten, och att de finns tillgängliga på Internet. Undersökningen är genomförd som en kvalitativ genreanalys. Materialet analyseras först utgående från kontexten och det samhälleliga sammanhanget enligt Vijay K. Bhatias metodik för analys av obekanta genrer. Det kommunikativa syftet, författaren och den tilltänkta läsarkretsen, dvs. målgruppen för kommunikationen, fastställs. Värderande adjektiv som uttrycker författarens hållning har plockats ur texten manuellt och med hjälp av konkordansprogrammet AntConc, och placerats i 16 kategorier enligt de värden de uttrycker. Varje genre analyseras sedan språkligt med utgångspunkt i adjektivlistorna, varefter resultaten jämförs med varandra. Undersökningen visar att pressmeddelandena innehåller det största antalet värderande adjektiv, medan informationsbroschyrerna innehåller det minsta antalet värderande adjektiv. Den Allmänna rapporten om Europeiska unionens verksamhet innehåller delar med tätt förekommande värderande adjektiv, i synnerhet i stycken som behandlar mer kontroversiella ämnen. I alla tre genrer sammanfaller ett högt antal värderande adjektiv med argumentativ text, och argumentativ text förekommer främst då ämnet som diskuteras rör sig på en mer abstrakt nivå, t.ex. om EU:s värderingar och grundläggande principer, eller då texten behandlar sådan politik som delar allmänhetens uppfattning. För EU utgör alla tre genrer viktiga kanaler för kommunikationen till medlemsstaternas medborgare, och EU kan genom sitt informationsmaterial och sina officiella publikationer informera om, förklara och marknadsföra sin verksamhet på ett sätt som avser att upprätthålla och förbättra EU:s image. Utarbetandet av lämpliga texter är ändå krävande på grund av den heterogena målgruppen, och det är en utmaning i sig att få fram rätt budskap bland det stora utbudet information som finns tillgängligt på Internet.

Rätt som argument : Leo Mechelin och finska frågan 1886-1912

Right as an Argument. Leo Mechelin and the Finnish Question 1886-1912 At the turn of the 20th century the Finnish Question rose up as a political and juridical issue at the international arena. The vaguely précised position of Finland in the Russian empire led to diverse conclusions concerning the correctness of the February manifesto of 1899. It was predominantly among a European elite of politicians, cultural workers and academics the issue rose some interest. Finns were active making propaganda for their cause, and they put an emphasis on the claim that the right was on the Finnish side. In the study Elisabeth Stubb compare the Finnish, Russian and European statements about the Finnish Question and analyse their use of right as an argument. The Finnish Question offers at the same time a case study of a national entity which possesses a political sphere of life but is not fully independent, and its possibilities to drive its interests in an international context. Leo Mechelin (1839-1914), the leader of the Finnish propaganda organization abroad, is used as a point of departure. The biographical stance is formed into a triangle, where Leo Mechelin, the idea of right and the Finnish Question abroad are the three cornerstones. The treatment of one cornerstone sheds a ligth on the two others. The metaphor of triangulation also worked as a method to reach "a third stance" in a scinetific and political issue that usually is polarised into two opposite alternatives. An adherence to a strict legal right could not in the end offer a complete, unquestionable and satisfactory solution to the Finnsih Question, it was dependent on "the right of state wisdom and sound insight". The Finnish propaganda abroad used almost completely alternative ways of making politics. The propaganda did not have a decisive effect on countries' official politics, but gained unofficial support, especially in the public opinion and in academic statements. Mechelin claimed that the political field was dependent on public opinion and scientific research. Together with the official politics these two fields formed a triangle that shared the task of balancing the political arena and preventing it from making unwise decisions of taking an unjust turn. The international sphere worked as a balancing part in the Finnish Question. Mechelin tried by claiming the status of state for Finland's part to secure the country a place at the official international arena. At the same time, and especially when the claim was not fully adopted, he emphasised, and in a European context worked for, that right would become the guiding light not only for international relations, but also for the policy making in the inner life of the state.

Hypertension, kardiotoxicitet och njursvikt i samband med tyrosinkinashämmaren sunitinib

Nybildning av blodkärl från tidigare existerande kärl, angiogenes, är ett väsentligt skede vid tumörtillväxt. Denna process regleras av bland annat tillväxtfaktorer, var av den vaskulära endoteliala tillväxtfaktorn har en central roll. Hämning av angiogenes kan ske antingen extracellulärt med hjälp av humaniserade monoklonala antikroppar eller intracellulärt med hjälp av småmolekylära hämmaren. Sunitinib är en småmolekylär multikinashämmare och inhiberar flera tyrosinkinasreceptorer som påverkar tumörtillväxten och metastasutvecklingen vid cancer. Sunitinibs främsta indikationer är gastrointestinala stromacellstumörer, metastaserad njurcellscancer och neuroendokrina tumörer i bukspottskörteln. Behandling med tyrosinkinashämmare orsakar biverkningar som hypertension, kardiotoxicitet och njursvikt, vilka antas bero på de hämmande effekterna på mål som inte är väsentliga för anti-cancer-aktiviteten (”off-target” biverkningar). Bland annat AMP-aktiverat proteinkinas (AMPK), ett kinas som upprätthåller metabolisk homeostas i hjärtat, inhiberas av sunitinib och antas framkalla kardiovaskulära biverkningar. För att reducera ”off-target” biverkningar strävar man till att hitta alternativ som minskar de skadliga effekterna utan att den terapeutiska aktiviteten försvagas. Bland annat ett begränsat kaloriintag har uppvisat skyddande effekt på hjärtat via mekanismer sammankopplade till ökad resistens mot oxidativ stress, inflammation och mitokondriell dysfunktion, samt avtagande apoptos och autofagi. Detta sker delvis genom aktivering av enzymet Sirt1. Syftet med den här studien var att undersöka ifall kaloribegränsning skyddar mot kardiovaskulära och renala biverkningar inducerade av sunitinib hos råttor. Dessutom studerades vilka signalkedjor i cellen som medverkar. I studien användes 40 spontant hypertensiva råttor samt 10 normotensiva Wistar-Kyoto råttor. Försöksdjuren delades in i fem grupper beroende på behandling; I WKY kontroll, II SHR kontroll, III SHR + kaloribegränsning 70 %, IV SHR + sunitinib 3 mg/kg och V SHR + sunitinib 3 mg/kg + kaloribegränsning 70 %. Behandlingsperioden var åtta veckor. Blodtrycket mättes varje vecka med svansmanchett, urinutsöndringen undersöktes vecka 4 och vecka 8 med metabolismburar, ultraljudsundersökning av hjärtat utfördes sista veckan och blodkärlens respons till acetylkolin och natriumnitroprussid studerades i samband med avlivning. Proteinerna Sirt1 och AMPK analyserades i hjärtat med Western blotting samt förekomsten av makrofagmarkören ED1 i njurarna med immunhistokemi. Studien visade att sunitinibdosen 3 mg/kg är mycket väl tolererbar hos råttor eftersom sunitinib inte orsakade högre blodtryck, kraftigare hypertrofi eller mer omfattande njurskada jämfört med obehandlade SHR- grupper. Utgående från resultaten kan man också konstatera att kaloribegränsningen har positiva kardiovaskulära effekter.

De "de" : Estudio histórico-comparativo de los usos y la semántica de la preposición "de" en español

El presente estudio supone un intento de describir y analizar el uso de la preposición "de" sobre la base de un corpus diacrónico, con énfasis en las diferentes relaciones semánticas que establece. Partiendo de un total de más de 16.000 casos de "de" hemos establecido 48 categorías de uso, que corresponden a cuatro tipos de construcción sintáctica, a saber, el uso de "de" como complemento de nombres (CN), verbos (CV), adjetivos (CA) y, finalmente, su uso como núcleo de expresiones adverbiales independientes (CI). El estudio consta de tres partes fundamentales. En la parte I, se introduce la Lingüística Cognitiva, que constituye la base teórica esencial del trabajo. Más exactamente, se introducen conceptos como la teoría del prototipo, la teoría de las metáforas conceptuales y la gramática cognitiva, especialmente las ideas de "punto de referencia" y "relación intrínseca" (Langacker 1995, 1999). La parte II incluye el análisis de las 48 categorías. En esta parte se presentan y comentan casi 2.000 ejemplos del uso contextual de "de" extraídos del corpus diacrónico. Los resultados más importantes del análisis pueden resumirse en los siguientes puntos: El uso de "de" sigue siendo esencialmente el mismo en la actualidad que hace 800 años, en el sentido de que todas las 48 categorías se identifican en todas las épocas del corpus. El uso de "de" como complemento nominal va aumentando, al contrario de lo que ocurre con su uso como complemento verbal. En el contexto nominal son especialmente las relaciones posesivas más abstractas las que se hacen más frecuentes, mientras que en el contexto verbal las relaciones que se hacen menos frecuentes son las de separación/alejamiento, causa, agente y partitivo indefinido. Destaca la importancia del siglo XVIII como época de transición entre un primer estado de las cosas y otro posterior, en especial en relación con el carácter cada vez más abstracto de las relaciones posesivas así como con la disminución de las categorías adverbales de causa, agente y partitivo. Pese a la variación en el contexto inmediato de uso, el núcleo semántico de "de" se mantiene inalterado. La parte III toma como punto de partida los resultados del análisis de la parte II, tratando de deslindar el aporte semántico de la preposición "de" a su contexto de uso del valor de la relación en conjunto. Así, recurriendo a la metodología para determinar el significado básico y la metodología para determinar lo que constituyen significados distintos de una preposición (Tyler , Evans 2003a, 2003b), se llega a la hipótesis de que "de" posee cuatro significados básicos, a saber, 'punto de partida', 'tema/asunto', 'parte/todo' y 'posesión'. Esta hipótesis, basada en las metodologías de Tyler y Evans y en los resultados del análisis de corpus, se intenta verificar empíricamente mediante el uso de dos cuestionarios destinados a averiguar hasta qué punto las distinciones semánticas a las que se llega por vía teórica son reconocidas por los hablantes nativos de la lengua (cf. Raukko 2003). El resultado conjunto de los dos acercamientos tanto refuerza como especifica la hipótesis. Los datos que arroja el análisis de los cuestionarios parecen reforzar la idea de que el núcleo semántico de "de" es complejo, constando de los cuatro valores mencionados. Sin embargo, cada uno de estos valores básicos constituye un prototipo local, en torno al cual se construye un complejo de matices semánticos derivados del prototipo. La idea final es que los hablantes son conscientes de los cuatro postulados valores básicos, pero que también distinguen matices más detallados, como son las ideas de 'causa', 'agente', 'instrumento', 'finalidad', 'cualidad', etc. Es decir, "de" constituye un elemento polisémico complejo cuya estructura semántica puede describirse como una semejanza de familia centrada en cuatro valores básicos en torno a los cuales se encuentra una serie de matices más específicos, que también constituyen valores propios de la preposición. Creemos, además, que esta caracterización semántica es válida para todas las épocas de la historia del español, con unas pequeñas modificaciones en el peso relativo de los distintos matices, lo cual está relacionado con la observada variación diacrónica en el uso de "de".

Exact analysis of Burgers equation on semiline with flux condition at the origin

The initial boundary value problem for the Burgers equation in the domain x greater-or-equal, slanted 0, t > 0 with flux boundary condition at x = 0 has been solved exactly. The behaviour of the solution as t tends to infinity is studied and the “asymptotic profile at infinity” is obtained. In addition, the uniqueness of the solution of the initial boundary value problem is proved and its inviscid limit as var epsilon → 0 is obtained.

Deutschland, Deutschland über alles : Tysk föreningsverksamhet i Finland och Sverige 1910-1950

The voluntary associations dealt with in this dissertation were ethnic clubs and societies promoting the interests of German immigrants in Finland and Sweden. The associations were founded at the end of the 19th century as well as at the beginning of the 20th century during a time in which migration was high, the civil society grew rapidly and nationalism flourished. The work includes over 70 different associations in Finland and Sweden with a number of members ranging from ten to at most 2, 500. The largest and most important associations were situated in Helsinki and Stockholm where also most of the German immigrants lived. The main aim of this work is to explore to what extent and how the changes in government in Germany during 1910 to 1950 were reflected in the structures and participants, financial resources and meeting places, networks and activities of the German associations in Finland and Sweden. The study also deals with how a collective German national identity was created within the German associations. The period between 1910 and 1950 has been described by Hobsbawm as the apogee of nationalism. Nationalism and transnationalism are therefore key elements in the work. Additionally the research deals with theories about associations, networking and identity. The analysis is mostly based on minutes of meetings, descriptions of festivities, annual reports and historical outlines about the associations. Archival sources from the German legations, the German Foreign Office, and Finnish and Swedish officials such as the police and the Foreign Offices are also used. The study shows that the collective national identity in the associations during the Weimar Republic mostly went back to the time of the Wilhelmine Empire. It is argued that this fact, the cultural propaganda and the aims of the Weimar Republic to strengthen the contacts between Germany and the German associations abroad, and the role of the German legations and envoys finally helped the small groups of NSDAP to infiltrate, systematically coordinate and finally centralize the German associational life in Finland and Sweden. The Gleichschaltung did not go as smoothly as the party wanted, though. There was a small but consistent opposition that continued to exist in Finland until 1941 and in Sweden until 1945. The collective national identity was displayed much more in Sweden than in Finland, where the associations kept a lower profile. The reasons for the profile differences can be found in the smaller number of German immigrants in Finland and the greater German propaganda in Sweden, but also in the Finnish association act from 1919 and the changes in it during the 1920s and 1930s. Finally, the research shows how the loss of two world wars influenced the associations. It argues that 1918 made the German associations more vulnerable to influence from Germany, whereas 1945 brought the associational life back to where it once started as welfare, recreational and school associations.

Role of CIP2A in carcinogenesis

Worldwide and notably in the developed countries, cancer is an increasing cause of morbidity and mortality, being the second most common cause of death after ischemic heart disease. Now and in the future new cancer cases need to be diagnosed earlier. Prognostic factors may be helpful in recognizing and handling those patients who need more aggressive therapy, and it is also desirable to predict treatment response accurately. Cancerous inhibitor of protein phosphatase 2A (CIP2A) is an oncoprotein predominantly expressed in malignant tissues and inhibiting protein phosphatase 2A (PP2A) activity; it is a promising target for cancer therapy. The aim of this thesis was to evaluate the prognostic role of CIP2A in solid cancers, and for this purpose to explore expression of CIP2A, and investigating regulation of CIP2A in order to gain insight into signalling pathways leading to alteration in prognosis. Patients diagnosed with gastric, serous ovarian, tongue, or colorectal cancer at Helsinki University Central Hospital were included. Tumour tissue microarrays assembled from specimens from these patients were prepared and stained immunohistochemically for CIP2A protein expression. Associations with clinicopathologic parameters and other biomarkers were explored, and survival analyses were done according to the Kaplan-Meier method. Study of the role of CIP2A in intracellular signalling in vitro involved gastric, ovarian, and tongue cancer cell lines. We found CIP2A to be highly expressed in gastric, ovarian, tongue, and colorectal cancer specimens. CIP2A was associated with clinicopathologic parameters characterizing an aggressive disease, namely advanced stage, high grade, p53 immunopositivity, and high proliferation index. CIP2A led to recognition of gastric, ovarian, and tongue cancer patients with poor prognosis, however, with a cancer type-specific cut-off level for prognostic significance. In tongue cancer, it served as an independent prognostic marker. In contrast, in colorectal cancer, CIP2A provided no prognostic value. In cancer cell lines, CIP2A was highly expressed at both protein and mRNA levels, and promoted cell proliferation and anchorage-independent growth. In gastric cancer, we demonstrated with a MYCER construct in mouse embryo fibroblasts that activation of MYC led to increased CIP2A mRNA expression, and hence we suggested that a positive feedback mechanism between CIP2A and MYC may potentiate and prolong the oncogenic activity of these proteins. We demonstrated in ovarian cancer an association between CIP2A and EGFR protein overexpression and EGFR gene amplification. In ovarian and tongue cancer cells we showed that depletion of EGFR downregulates CIP2A expression. In conclusion, high CIP2A expression occurred frequently among patients with aggressive disease. CIP2A may serve as a prognostic marker in gastric, ovarian, and tongue cancer and thus may help in tailoring therapy for cancer patients. The positive feedback mechanism between CIP2A and MYC, as well as the positive regulation of CIP2A by EGFR, are a few signalling pathways regulating and regulated by CIP2A. These and other mechanisms need to be studied further, however. CIP2A is a potential target for therapy, and its potential role as predictive marker and as a tumour marker in serum requires exploration.

Modeling and control of unified power flow controller for transient stability

FACTS controllers are emerging as viable and economic solutions to the problems of large interconnected ne networks, which can endanger the system security. These devices are characterized by their fast response, absence of inertia, and minimum maintenance requirements. Thyristor controlled equipment like Thyristor Controlled Series Capacitor (TCSC), Static Var Compensator (SVC), Thyristor Controlled Phase angle Regulator (TCPR) etc. which involve passive elements result in devices of large sizes with substantial cost and significant labour for installation. An all solid-state device using GTOs leads to reduction in equipment size and has improved performance. The Unified Power Flow Controller (UPFC) is a versatile controller which can be used to control the active and reactive power in the Line independently. The concept of UPFC makes it possible to handle practically all power flow control and transmission line compensation problems, using solid-state controllers, which provide functional flexibility, generally not attainable by conventional thyristor controlled systems. In this paper, we present the development of a control scheme for the series injected voltage of the UPFC to damp the power oscillations and improve transient stability in a power system. (C) 1998 Elsevier Science Ltd. All rights reserved.

Improved algorithm for optimum reactive power allocation

An improvised algorithm is presented for optimal VAr allocation in a large power system using a linear programming technique. The proposed method requires less computer memory than those algorithms currently available.

Methodology for alleviation of voltage excursions in large power systems

This paper presents a method for minimizing the sum of the square of voltage deviations by a least-square minimization technique, and thus improving the voltage profile in a given system by adjusting control variables, such as tap position of transformers, reactive power injection of VAR sources and generator excitations. The control variables and dependent variables are related by a matrix J whose elements are computed as the sensitivity matrix. Linear programming is used to calculate voltage increments that minimize transmission losses. The active and reactive power optimization sub-problems are solved separately taking advantage of the loose coupling between the two problems. The proposed algorithm is applied to IEEE 14-and 30-bus systems and numerical results are presented. The method is computationally fast and promises to be suitable for implementation in real-time dispatch centres.

Neural network based power system damping controller for SVC

The development of a neural network based power system damping controller (PSDC) for a static VAr compensator (SVC), designed to enhance the damping characteristics of a power system network representing a part of the Electricity Generating Authority of Thailand (EGAT) system is presented. The proposed stabilising controller scheme of the SVC consists of a neuro-identifier and a neuro-controller which have been developed based on a functional link network (FLN) model. A recursive online training algorithm has been utilised to train the two networks. The simulation results have been obtained under various operating conditions and disturbance cases to show that the proposed stabilising controller can provide a better damping to the low frequency oscillations, as compared to the conventional controllers. The effectiveness of the proposed stabilising controller has also been compared with a conventional power system stabiliser provided in the generator excitation system

Neural network based power system damping controller for SVC

The development of a neural network based power system damping controller (PSDC) for a static Var compensator (SVC), designed to enhance the damping characteristics of a power system network representing a part of the Electricity Generating Authority of Thailand (EGAT) system is presented. The proposed stabilising controller scheme of the SVC consists of a neuro-identifier and a neuro-controller which have been developed based on a functional link network (FLN) model. A recursive online training algorithm has been utilised to train the two networks. The simulation results have been obtained under various operating conditions and disturbance cases to show that the proposed stabilising controller can provide a better damping to the low frequency oscillations, as compared to the conventional controllers. The effectiveness of the proposed stabilising controller has also been compared with a conventional power system stabiliser provided in the generator excitation system.

Fuzzy Expert Approach with Curtailed Controllers for Improved Reactive Power Dispatch

This paper addresses the problem of curtailing the number of control actions using fuzzy expert approach for voltage/reactive power dispatch. It presents an approach using fuzzy set theory for reactive power control with the purpose of improving the voltage profile of a power system. To minimize the voltage deviations from pre-desired values of all the load buses, using the sensitivities with respect to reactive power control variables form the basis of the proposed Fuzzy Logic Control (FLC). Control variables considered are switchable VAR compensators, On Load Tap Changing (OLTC) transformers and generator excitations. Voltage deviations and controlling variables are translated into fuzzy set notations to formulate the relation between voltage deviations and controlling ability of controlling devices. The developed fuzzy system is tested on a few simulated practical Indian power systems and modified IEEE-30 bus system. The performance of the fuzzy system is compared with conventional optimization technique and results obtained are encouraging. Results obtained for a modified IEEE-30 bus test system and a 205-node equivalent EHV system a part of Indian southern grid are presented for illustration purposes. The proposed fuzzy-expert technique is found suitable for on-line applications in energy control centre as the solution is obtained fast with significant speedups with few number of controllers.