Clemson University Electric Power Research Association CHANDANA BOMMAREDDY CLEMSON UNIVERSITY DG VOLTAGE CONTROL IN AN ISLANDING MODE OF OPERATION

Presentation Outline Purpose of the presentation Purpose of the presentation Distributed Generation and the increasing interest in distributed resources Distributed Generation and the increasing interest in distributed resources Grid-connected and stand-alone modes of operation Grid-connected and stand-alone modes of operation Simulation of an IEEE bus feeder using PSCAD Simulation of an IEEE bus feeder using PSCAD Simulation of synchronous generator using PSCAD Simulation of synchronous generator using PSCAD Simulation of induction generator using PSCAD Simulation of induction generator using PSCAD To study their impact on the voltage in both the modes and compare the results To study their impact on the voltage in both the modes and compare the results Conclusion and future work Conclusion and future work Clemson University Electric Power Research Association

Operation of distributed generation systems (DGS) in a standalone AC power supply Operation of distributed generation systems (DGS) in a standalone AC power supply Voltage fluctuations due to many reasons Voltage fluctuations due to many reasons Distribution networks and voltage stability Distribution networks and voltage stability Control voltage and frequency to the improvement of the power quality Control voltage and frequency to the improvement of the power quality Clemson University Electric Power Research Association Purpose of the Presentation

Distributed Generation Why is Distributed Generation so popular ? Speed & mobility Higher efficiencies than centralized generation Reliability of power Flexibility & choice to consumers Reduction of transmission and distribution costs Suited for small-scale generation in the commercial and industrial sectors Clemson University Electric Power Research Association

Distributed Generation Technologies Considering only the electrical characteristics there are three different DG types: Synchronous generator Asynchronous generator Photo Voltaic Other Clemson University Electric Power Research Association

Different modes of operation The utility is used as reference for voltage and frequency. DG is assumed to be disconnected from the grid in this mode of operation. Stand-alone mode The DG is disconnected from the grid and is its in maximum mode of operation GRIDDG LOAD 4.16 / 0.48 kV 4.16 kV480V, 1.5 MW Grid-connected mode Clemson University Electric Power Research Association DG is assumed to be connected and operating in parallel with the grid in this mode of operation. Grid and DG connected mode

Modeling of power system components IEEE 13 Node Test Feeder Clemson University Electric Power Research Association

Simulation of synchronous generator Clemson University Electric Power Research Association

Simulation of induction generator

Results and Discussions Clemson University Electric Power Research Association Grid-connected mode with and without capacitors

Synchronous Generator with and without capacitor Clemson University Electric Power Research Association Grid and DG mode

Induction Generator with and without capacitor Clemson University Electric Power Research Association

Stand-alone mode Clemson University Electric Power Research Association Synchronous Generator Induction Generator

CONCLUSIONS The steady state models developed, simulate the operation of synchronous generator and induction generator in the stand-alone and grid-connected modes. The steady state models developed, simulate the operation of synchronous generator and induction generator in the stand-alone and grid-connected modes. Both the models were used to study the comparison of voltage magnitudes in the two different modes of operation of the DG. Both the models were used to study the comparison of voltage magnitudes in the two different modes of operation of the DG. Results show the voltage magnitudes dropped significantly in the stand- alone mode. Results show the voltage magnitudes dropped significantly in the stand- alone mode. Capacitors connected at selected buses improved the voltage magnitudes by 3 - 6% which is a considerable increase. Capacitors connected at selected buses improved the voltage magnitudes by 3 - 6% which is a considerable increase. Original capacitors in the grid-connected mode may not help the islanding mode of operation. Original capacitors in the grid-connected mode may not help the islanding mode of operation. Clemson University Electric Power Research Association

FUTURE WORK I. Develop the following control mechanisms to control the voltage in the stand-alone mode of operation at 60 Hz : a) Synchronous Condenser b) Static VAR Compensator c) Tap Changing Transformers d) Voltage Regulator e) Other II. Develop detailed models of some DG control methods that are described in Part I to control harmonics due : a) Non linear loads b) DG model Clemson University Electric Power Research Association

QUESTIONS ? THANK YOU Clemson University Electric Power Research Association