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Title: Steady state and transient stability analysis of A.C.-D.C. power systems
Author: Tam, Cheuk Cheung
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1969
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The outlook for h.v. d.c. in the next decade is promising with three schemes close to commissioning and four more planned. The total capacity of these seven new schemes will be over 12,000 MW. Ever since the beginning of h.v.d.c. activities the need to analyse the different aspects of mixed a.c./d.c. power systems has led to many different methods of representing d.c. converters and systems. A classification of these methods is proposed and forms the basis for an extensive discussion of these methods. The interaction between d.c. converters and weak a.c. systems is considered and its effect on d.c. link power transfer limit is studied. Converter characteristics are discussed and causes of possible power oscillations are explained. A method for co-ordinating system transformer and converter taps is developed. An operation chart for a simple d.c. link is presented. An a.c./d.c. load flow program is developed which can accommodate both single and double pole d.c. links with full conventional controls and has a comprehensive tap changer subroutine. This program provides the initial conditions for the transient analysis of a.c./d.c. systems. It has also been used to investigate the effect of the slope of converter characteristics, and a particular problem of non-convergence when an a.c. line outage is simulated. For the transient analysis of a.c./d.c. systems a method using matrix algebra is developed and applied to a simple system. A transition matrix method for solving the d.c. line equations and a recursive method for representing d.c. link controls is described. The particular problem of suddenly isolating a generator onto a d.c. link is considered and two methods of control in order to limit voltage and machine frequency excursions are studied. Methods of digital solution of differential equations using ordinary programing language and digital analog simulation languages are described. The advantages and disadvantages of these two approaches are discussed, and an extensive discussion of the desirable features of digital analog simulation languages is presented.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available