CONTROL OF DYNAMIC VOLTAGE RESTORER FOR VOLTAGE SAG MITIGATION by uee19558

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									CONTROL OF DYNAMIC VOLTAGE RESTORER
FOR VOLTAGE SAG MITIGATION




                                  ICTS 2008
        Glanny M Ch Mangindaan
               M Ashari
             Mauridhi H P
DYNAMIC VOLTAGE RESTORER
 Voltage sags are usually caused by a
 short circuit current flowing into a
 fault on a transmission or distribution
 line, where the magnitude and phase
 of the faulted voltage usag during the
 sag at the point of common coupling
 (PCC) are determined by the fault
 and supply impedances using the
 equation:

                     Zf
      usag = E
                  Z f + Zs

 DVR installed on a critical load,
 restores the line voltage to its
 nominal value within the response
 time of a few millisecond thus
 avoiding any power disruption to the
 load
VARIATION VOLTAGE MAGNITUDES
AND DURATION IEEE 1159




                              Transient
                                                              Swell                 Overvoltage
                      110%

                                                              Normal operating voltage
    Event magnitude


                       90 %
                              Notch/transient


                                                            Voltage Sag                  Undervoltage



                       10 %
                                                  Momentary Temporary Sustianed interuption
                                                0.5 cycle       3 sec        1 min
                                                                        Event duration
POWER SYSTEM WITH DVR
VOLTAGE REGULATOR
SIMULATION WITH PI
CONTROLLER
SIMULATION WITH FL
CONTROLLER
SIMULATION WITH CPNN
CONTROLLER
RESULTS
 When compensate the voltage sag at the critical
 load, DVR produce a harmonics distortion fed
 from series transformer as an injection voltage
 to the critical load. Using the FFT analysis to
 analyze the THD for the voltage signal, result
 that the fuzzy logic (0.82%) are better than PI
 (1.44%), and the counterpropagation neural
 network (0.79%) slightly better than fuzzy logic
 for the THD at the one phase with the same
 fault.
CONCLUSION
 This paper has presented result from DVR simulation at
 the low voltage (0.38 kV) distribution line. The DVR is
 designed to protect the critical load against voltage sag
 from 0.9-p.u. up to 0.1-p.u. remain voltage.
 Counterpropagation neural network control and fuzzy
 logic control provides good voltage regulation
 capabilities than a PI controller, that the control
 parameters are fixing.
 Both artificial intelligent results a good performance to
 mitigate the voltage sags. The hybrid method of
 artificial intelligent to be applied is the interesting field
 for future research.
END OF PRESENTATION

								
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