In the modern power system the reactive power compensation is one of the main issues, the transmission of active power requires a difference in angular phase between voltages at the sending and receiving points (which is feasible within wide limits), whereas the transmission of reactive power requires a difference in magnitude of these same voltages (which is feasible only within very narrow limits). The reactive power is consumed not only by most of the network elements, but also by most of the consumer loads, so it must be supplied somewhere. If we can't transmit it very easily, then it ought to be generated where it is needed." (Reference Edited by T. J. E. Miller, Forward Page ix).Thus we need to work on the efficient methods by which VAR compensation can be applied easily and we can optimize the modern power system. VAR control technique can provides appropriate placement of compensation devices by which a desirable voltage profile can be achieved and at the same time minimizing the power losses in the system. This report discusses the transmission line requirements for reactive power compensation. In this report thyristor switched capacitor is explained which is a static VAR compensator used for reactive power management in electrical systems. Seminar Topic For Electrical and Electronics Engineering (EEE)

2. kW: what we can use..
kVAr: loss..
kVA: the total capacity available

3. 1. The voltage regulation.
2. Increased system stability.
3. Better utilization of machines connected to the system.
4. Reducing losses associated with the system; and
5. To prevent voltage collapse as well as voltage sag.

4. 1. Thyristors switched capacitors (TSCs)
2. Thyristor controlled reactor (TCRs)
3. Combined TSC and TCR
4. Thyristor controlled series capacitor (TCSC)
1 3
2

5. 1. Capacitor bank
2. TSC reactor
3. Thyristor valve

6. 1
2

7. When the TSC is turned on….

9. a. TSC generates no harmonics.
b. No filtering is required.
c. SVCs have been built with only TSCs .
d. relatively cost-effective.
a) reactive power output can only be varied in steps.
b) For continuously variable reactive power output, a TCR is required.

10. TCS can balance the voltage and current to normal levels, as we know
that there is reactive power due to capacitive and inductive
elements in the grid which can make the current and voltage
phase difference, due to which the real power in the system reduces from
the ideal level, but after we introduce the compensation device, the
current and voltage waveforms have same phase, and due to this
compensation effect, power in the system achieves to the desired
value with stable voltage.

11. 1. Transmission system reactive power compensation , B. F. Wollenberg Minnesota Univ., Duluth, MN,
USA, Date of Conference: 2002 Page(s): 507 - 508 vol.1 Print ISBN:0-7803-7322-7, INSPEC Accession
Number: 7386352, DOI:10.1109/PESW.2002.985054 , Publisher: IEEE
2. T.J.E Miller, Reactive Power Control In Electrical Systems, John Willey & Sons, 1982
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