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IEC06000595 V1 EN-US
Figure 90: Thyristor switched series capacitor
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IEC06000596 V1 EN-US
Figure 91: Thyristor controlled series capacitor
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Line current
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Current through the thyristor
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Voltage over the series capacitor
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Rated reactance of the series capacitor
A thyristor controlled series capacitor (TCSC) allows continuous control of the series capacitor
reactance. This is achieved by adding current through the capacitor via the parallel thyristor
. The main circuit of the TCSC consists of a capacitor bank and a
thyristor controlled inductive branch connected in parallel. The capacitor bank may have a
value of for example, 10...30 Ω/phase and a rated continuous current of 1500...3000 A. The
capacitor bank for each phase is mounted on a platform providing full insulation towards
earth. The thyristor valve contains a string of series connected high power thyristors with a
maximum total blocking voltage in the range of hundreds of kV. The inductor is an air-core
reactor with a few mH inductance. The wave forms of a TCSC in capacitive boost mode are
shown in figure
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IEC06000597 V1 EN-US
Figure 92: TCSC wave forms presented in capacitive boost mode for a typical 50Hz
system
Section 7
1MRK 505 343-UEN B
Impedance protection
162
Application manual
Summary of Contents for Relion 670 series
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