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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Study of Target Frequency Bond for Frequency Control Performance Score Calculations in an Isolated System

Lee, Hung-hsi 06 September 2010 (has links)
Power system frequency is one of the key performance indices of system operation. Abnormal frequency deviations would incur negative impacts to power equipments and service quality. Thus, it is important to operate and regulate the system frequency within an acceptable range. North American Electric Reliability Corporation (NERC) has been using a Control Performance Standard (CPS) for frequency control performance assessment since 1997 which uses system frequency and inter--area power flow to evaluate the power system control performance. This thesis presents a design of CPS for isolated system and the results of Taiwan Power Company frequency control performance based on the proposed CPS1 formulation.
2

The economic analysis of relaxing frequency control

Chown, Graeme Andrew 12 August 2008 (has links)
Abstract will not load on to DSpace
3

Frequency control ancillary services in large interconnected systems

Diouf, Edmond January 2013 (has links)
This research focuses on frequency control ancillary services in large interconnected systems. It analyses and assesses possible alternatives for optimal and innovative solutions of major frequency control issues in large interconnected systems within liberalised electricity markets. Possible improvements in the performance of frequency control are identified. A framework of frequency control ancillary services in large interconnected systems by including loads and wind generation is also proposed.The research has been motivated by the paucity of research in power system dynamics focusing on large interconnected systems such as the European synchronous system and the Eastern interconnection which experience important frequency control challenges. These challenges include:- Decline in frequency response in the Eastern interconnection - Deterministic frequency deviations observed at the top of the hours in the European synchronous systemFrequency control issues became critical when electricity markets were deregulated and frequency control became an ancillary service with a decidedly commercial focus. This commercial focus has spawned a lot of work on frequency control markets and economics whereas not much research has been devoted to dynamic simulation of large interconnected systems. Apart from this commercial focus, frequency control in large interconnected systems is still based on historical practices mainly because changes suggested in the literature can be barely applied in large interconnected systems. This is essentially because dynamic simulation studies are uncorrelated with frequency control markets and economics. More specifically, dynamic studies do not take into account the characteristics of each reserve activated and also the way the reserve is activated. With the deregulation of the electricity market, reserve is considered as a product and not necessarily a response provided by a unit. The main objectives of this research therefore are to solve critical frequency control issues in large interconnected deregulated electricity systems, which may present potential economic benefits. To achieve these objectives, frequency control in large interconnected systems is studied by considering on one hand frequency control theory and on the other hand its implementation in practice taking account of frequency control ancillary service markets as well as the economics and practical consequences of frequency control. This approach is necessary to accommodate the future evolution of frequency control in large interconnected systems. The proposed approach is illustrated through a model of frequency control in the European synchronous system, where practices are better known, are clearly standardised and also where frequency data has been obtained.
4

Study of an Alternative Dispatch Planning for the Salvadorian Electrical Market Based on Generators Outage Risk and Optimum AGC-Performance

Adonay, Francisco 29 June 2009 (has links)
A proposal for the spinning reserve assessment and allocation for El Salvador¡¦s Deregulated Electricity Market is formulated. Traditionally, the Independent System Operator calculates the spinning reserve as percentage of the forecast demand. And Automatic Generation Control (AGC) is allocated based on the partition factor. The reserve calculation neither reflects consistency achieving its main objective, reliability, nor is optimum performance control reached by the allocating mechanism. In the proposed method, the spinning reserve is estimated taking into account the generators outage ratio and AGC is allocated based on the North American Electric Reliability Corporation¡¦s Control Performance Standard-1. The allocation problem is solved with an improved Particle Swarm Optimization algorithm with a technique to modify the inertial factor on each iteration. The proposed method exhibits better results and it matches the Salvadorian technical requirements and market characteristics.
5

A methodology to enable wind farm automatic generation control

Han, Hai-Yue 03 January 2012 (has links)
Over the last decade the increase in penetration of wind power and its variable nature has begun to add considerable stress to and threatened the stability of the nation's grid. In order to continue growth wind farms will need to have the ability to participate in the same grid frequency regulation as traditional generating sources. The goal of this research is to explore the use of energy storage devices to provide wind farms with a method to regulate their power output and the grid frequency. Using energy storage, this research aims to allow wind farms to participate in automatic generation control (AGC). Software simulations were performed to design an advanced energy storage controller that will allow maximum participation in AGC. A comprehensive in-lab grid was constructed to produce experimental results for this work and was used to evaluate the performance of the advanced energy storage controller. The first stage of this research aims to use super-capacitors to balance rapid excursions in frequency and wind power output while the second stage of this research will preliminarily explore the use of a zinc-bromine flow cell battery for medium-scale, sustained excursions in frequency and wind power output. Results show that wind farms are capable of participation in AGC with the addition of an energy storage device, but the amount of participation is heavily reliant on the amount of energy storage available. / Graduation date: 2012
6

Aplicação do software scicoslab para análise do controle automático de geração de sistemas elétricos de potência / Application of ScicosLab software for analysis of automatic generation control of electric power systems

Oda, George 22 June 2012 (has links)
The purpose of this paper is to show that the software ScicosLab can be used as an interesting and effective computational tool to analyze the automatic generation control of electric power systems. Firstly it is presented the software and, afterwards, the concepts and definitions of rotational movements in order to develop mathematical models for the generators equipped with steam turbines or hydraulic turbines and speed governors, and for their electrical loads. For the studies it is used a system comprised by two distinct interconnected areas where a load increase in one area is simulated without/with the tieline, ignoring, and then considering the primary and supplementary controls. Finally, it is analyzed a more realistic system with three distinct areas extracted from the Brazilian power system. The computational results show graphically the variations of the two main quantities of interest: the frequency of each area of the system and the tieline power. These quantities allow the evaluation of the system behavior after a disturbance that affects the generation-load balance. Within the above context, it is verified that the ScicosLab computer package effectively models and simulates the load-frequency control of power systems, qualifying, therefore, as an excellent alternative to replace any similar program which requires license payment. / A proposta deste trabalho é mostrar que o software ScicosLab pode ser utilizado como uma ferramenta computacional, interessante e eficaz, para analisar o controle automático de geração de sistemas elétricos de potência. Inicialmente é apresentado o software e, em seguida, os conceitos de movimentos rotativos que permitem desenvolver os modelos matemáticos para os geradores equipados com turbinas a vapor ou hidráulica e reguladores de velocidade, e para suas cargas elétricas. Para possibilitar os estudos é utilizado um sistema constituído por duas áreas distintas interligadas, onde é simulado um aumento de carga em uma destas áreas, sem e com a linha de interligação, desconsiderando e, em seguida, considerando os controles primário e suplementar. Finalmente, analisa-se um sistema mais realístico com três áreas distintas extraído do sistema elétrico brasileiro. Os resultados computacionais mostram graficamente as variações das duas principais grandezas de interesse: a frequência de cada área do sistema e a potência da linha de interligação. Estas grandezas permitem avaliar o comportamento do sistema após uma perturbação que afeta o balanço geração-carga. Considerando o exposto acima, constata-se que o pacote computacional ScicosLab modela e simula eficazmente o controle carga-frequência de sistemas elétricos de potência, qualificando-se, portanto, como uma excelente alternativa para substituir qualquer programa similar que exige pagamento de licença. / Mestre em Ciências
7

Um novo modelo para representação da regulação primária e secundária de frequência no problema de fluxo de potência e fluxo de potência ótimo

La Gatta, Paula Oliveira 05 March 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-01T14:29:29Z No. of bitstreams: 1 paulaoliveiralagatta.pdf: 1917786 bytes, checksum: 627585584595873c205fcbcf5c79980f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:01:23Z (GMT) No. of bitstreams: 1 paulaoliveiralagatta.pdf: 1917786 bytes, checksum: 627585584595873c205fcbcf5c79980f (MD5) / Made available in DSpace on 2016-07-13T16:01:23Z (GMT). No. of bitstreams: 1 paulaoliveiralagatta.pdf: 1917786 bytes, checksum: 627585584595873c205fcbcf5c79980f (MD5) Previous issue date: 2012-03-05 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho são propostas duas formulações de importantes ferramentas para análise de redes em regime permanente, onde são consideradas equações que descrevem o comportamento do controle primário e secundário de frequência em sistemas elétricos de potência. A primeira proposta é baseada em uma formulação do problema de fluxo de potência convencional e a segunda uma formulação do fluxo de potência ótimo. A formulação de fluxo de potência proposta é desenvolvida a partir de uma metodologia genérica de representação de dispositivos de controle. Esta metodologia consiste em incorporar as equações que modelam dispositivos de controle ao problema básico de fluxo de potência em coordenadas polares, formando um sistema de equações de ordem (2nb+nc). O fluxo de potência desenvolvido é capaz de estimar os desvios de frequência do sistema devido a uma perturbação da carga. Por outro lado, o fluxo de potência ótimo proposto é capaz de identificar montantes e locais de corte carga, de forma a manter a frequência do sistema em uma faixa aceitável de operação. A formulação proposta de FPO consiste em incluir no problema equações de igualdade e desigualdade associadas com o controle primário de frequência e geração de potência ativa. Os desenvolvimentos propostos para o fluxo de potência convencional foram implementados no ambiente MatLab®. Para solução do fluxo de potência ótimo utilizou-se um pacote comercial de otimização, denominado LINGO®. A avaliação do fluxo de potência e fluxo de potência ótimo propostos é feita através do estudo de sistemas tutoriais e do sistema New England. A validação da análise de desvios de frequência é feita através da utilização do programa ANATEM, desenvolvido pelo CEPEL. Os resultados obtidos mostram as vantagens da utilização das formulações propostas. / This work proposes a new formulation for both the conventional power flow and the optimal power flow formulation, in which the steady-state equations describing the primary and secondary frequency control in electrical power systems are included. The proposed power flow formulation is based on a flexible methodology for the representation of control devices. Such methodology incorporates equations that model control devices into the basic power flow formulation in polar coordinates, generating an augmented system of equations having order (2nb + nc). The developed power flow is able to estimate the system frequency deviation due to a load disturbance. On other hand, the proposed optimum power flow formulation is able to identify the minimum load shedding necessary to maintain the system frequency in an acceptable range of operation. The proposed OPF formulation includes additional equality and inequality constraints to represent the steady state primary frequency control as a function of the active power generation. The proposed development for the conventional power flow was made using the MATLAB® environment. The optimal power flow solution used a commercial optimization package called LINGO®. The evaluation of the proposed power flow and optimal power flow formulations were made through the study of small test systems and the New England test system. Validations of the frequency deviation analysis were made using the program ANATEM, developed by CEPEL. The results obtained show the advantages of using the proposed formulations.

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