design and implementation of thyristor switched shunt capacitors a ...

Figure 3.4 Discharge reactor connection diagram (a) parallel to each capacitor,
(b) across two phases. . . . . . . . . . . . . . . . . . . . . . 53
Figure 3.5 Capacitor internal structure. . . . . . . . . . . . . . . . . . . 54
Figure 3.6 Double-star connection for unbalance protection. . . . . . . . 55
Figure 3.7 PSCAD model of the (a) TSC circuit, (b) harmonic extraction. 57
Figure 3.8 Frequency characteristics of TSC and the passive filter located
in TKİ, Orhaneli/Bursa. The passive filters are tuned to 5th (240 Hz)
and 7 th (340 Hz) harmonics. . . . . . . . . . . . . . . . . . . . . . . 58
Figure 3.9 Thyristor gate triggering. . . . . . . . . . . . . . . . . . . . . 60
Figure 3.10 Equivalent circuit for snubber design for TSC. . . . . . . . . 61
Figure 3.11 Thyristor turn-off waveforms, [43]. . . . . . . . . . . . . . . . 62
Figure 3.12 Heatsink profile for the reduction of junction temperature. . 64
Figure 3.13 The current distribution of back-to-back connected thyristors
in the steady state. . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Figure 3.14 Block diagram of TSC control scheme. . . . . . . . . . . . . . 66
Figure 3.15 The view of EU control card designed for TSC. . . . . . . . . 68
Figure 3.16 The connection scheme of the microcontroller, type PIC16F877. 69
Figure 4.1 Laboratory prototype of Thyristor and Contactor switched
shunt filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Figure 4.2 Circuit representations of four different switching scheme. . . 77
Figure 4.3 Resultant Waveforms of the turn-on transient with contactor
when the capacitors are initially charged. . . . . . . . . . . . . . . . 80
Figure 4.4 Resultant line-to-line voltage and phase current of the turn-on
transient with contactor when the capacitors are initially discharged. 81
Figure 4.5 Resultant 3φ phase current waveform, the response time and
the settling time of the turn-on transient with contactor. . . . . . . 83
Figure 4.6 Resultant Waveforms of the turn-off transient with contactor. 84
Figure 4.7 Resultant Waveforms of the turn-on transient with contactor
when the capacitors are initially charged. . . . . . . . . . . . . . . . 86
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