"Static capacitors as an element of transmission and distribution circuits first appeared in the form of shunt capacitors. These shunt capacitors were primarily used in power factor correction. They can be regarded as a load in the circuit which draws a loading current. This loading current fleeing through the reactive line produces a voltage rise, thus reducing the voltage drop between sending and receiving ends. This phenomenon helps the voltage control of the feeder as well as power factor correction. The disadvantage of the shunt capacitor is its inflexibility. The shunt capacitor is connected across the line; hence the voltage across its terminals is constant. The idea of connecting the capacitor in series with the line rather than parallel, thus making the capacitor an element of the line, opened a new field in transmission and distribution engineering. The voltage across the terminals of the series capacitor is not constant but is directly proportional to the line current. This characteristic of the series capacitor makes it extremely valuable in some applications; however, it is the same characteristic which in some cases makes its application difficult. The series capacitor as a voltage regulator in distribution systems proved very useful and economical. It found a large application field associated with electric arc furnaces and electric welders. The first difficulty in the application of series capacitor showed itself in its protection. An air gap, which flashes over at a certain voltage above the rated voltage of the capacitor, and short circuits the capacitor unit under abnormal conditions, constitutes the basic principle of the protection device of the series capacitor.
Series capacitors should also be protected against dielectric failure and continuous operation under over-load conditions. Furthermore from the standpoint of transient stability of power systems, series capacitors should be reinserted in the circuit as soon as the fault is cleared. These operations are provided by fast acting relays.
During recent years, the necessity of transmitting large blocks of power over long distances and the comparatively high costs, losses and difficulties associated with the construction of large synchronous condensers, opened an application field for series capacitors in transmission lines. The series capacitor proved itself to be very useful and economical in this field. However new problems associated with the various application of series capacitors arose. Self-excitation of synchronous machines, self-excitation of induction motors, hunting of synchronous machines, and ferro-resonance in transformers are some of the important problems which are discussed in the body of the thesis. A solution for and methods of correcting the difficulty are established.
In this thesis the author has made an attempt to cover as many problems associated with the use of series capacitors as possible emphasizing some important points, and briefly explaining others. One other thing which interested the author in this subject is that in his country, Turkey, natural resources available for obtaining electric energy are located long distances from load centers thus making the transmission of large amounts of power over long distances necessary. Furthermore, in Turkey large industrial and residential lighting loads are both concentrated in big cities raising the problem of voltage regulation. Since series capacitors prove useful and economical both in voltage regulation and In transmission of large blocks of power over long distances, the author found this subject worthy of serious study. In this survey type of thesis the author tried to present some of the important principles explained in different articles with some minor contributions of his own"--Introduction, pages 1-4.
Lovett, I. H.
Electrical and Computer Engineering
M.S. in Electrical Engineering
Missouri School of Mines and Metallurgy
v, 61 pages
© 1951 Emcet Bilgeer, All rights reserved.
Thesis - Open Access
Electric power distribution -- Mathematical models
Electric power systems -- Equipment and supplies
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Bilgeer, Emcet, "Series capacitors" (1951). Masters Theses. 3021.