This paper presents the comparative improvement of the voltage profile of the distributed power system using a Dynamic Voltage Restorer (DVR) and a Distributed Static Synchronous Compensator (D-STATCOM). The IEEE benchmark 13-bus distributed power system is used to present the distributed power grid. A proposed DVR is connected in series with bus 632 while a D-STATCOM is connected in parallel with bus 632. Comparative simulation results of the system with DVR and D-STATCOM are performed by using commercial MATLAB software. It can be concluded from the simulation results that DVR is suitable to mitigate the voltage sag of the load side while D-STATCOM can enhance the voltage stability margin of the buses that are located near the connected bus of the proposed D-STATCOM in the distributed grid.
1. Distributed Power System
2. Dynamic Voltage Restorer (DVR)
3. Distributed Static Synchronous Compensator (D-STATCOM)
4. Voltage Quality.
DVR AND STATCOM MODELS:
Figure 1. Basic DVR Model
Figure 2. Basic D-STATCOM Model
EXPECTED SIMULATION RESULTS:
a. Voltage at bus 633 without DVRlD-STATCOM
b. Voltage at bus 646 with D-STATCOM
c. Voltage at bus 633 with D-STATCOM
d. Voltage at bus 684 with D-STATCOM
e. Voltage at bus 646 with DVR
f. Voltage at bus 633 with DVR
g. Voltage at bus 684 with DVR
Figure 3. Simulation results of the studied system when a three-phase short-circuit fault happened at bus 633.
In this paper, the voltage stability improvement of an IEEE I3-bus distributed power system has been presented. A DVR and a D-STATCOM have been proposed and integrated to the studied system. Based on the results from the simulation, it can be concluded that the proposed DSTATCOM is better than DVR for improving the voltage quality of the distributed power system under a severe fault happened.
 M. Bollen, "Understanding Power Quality Problems - Voltage Sags and Interruptions", IEEE Press Series on Power Engineering – John Wiley and Sons, Piscataway, USA, 2000.
 Math H.J. Bollen, Understanding power quality problems: voltage sags and interruptions, IEEE Press, New York, 2000.
 FACTS controllers in power transmission and distribution by K. R. Padiyar ISBN: 978-81-224-2541-3.
 B. Singh, A. Adya, A. P. Mittal and J. R. P. Gupta, "Modeling, Design and Analysis of Different Controllers for DSTATCOM," 2008 Joint International Conference on Power System Technology and IEEE Power india Conference, New Delhi, 2008, pp. 1-8.
 Devaraju, V. C. Reddy and M. Vijaya Kumar, "Performance of DVR under different voltage sag and swell conditions", ARPN Journal of Engineering and Applied Sciences, Vol. 5, No. 10,2010, pp. 56-64.