**ABSTRACT:**

This paper deals with a new design dynamic model of synchronous-reference- frame (SRF)-based control in three phase system under different load considerations to improve power quality by using power conditioner with multi converters. The proposed MCUPQC system can regulate the load voltages/bus voltages on Parallel power distribution systems under balanced and distorted load conditions and obtain the state space model for MC-UPQC. The simulation results to support the SRF-based control method presented in this paper is done using Matlab/Simulink.

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**KEYWORDS:**

- Power quality (PQ)
- Active power filter (APF)
- Synchronous reference frame (SRF) and multi converter
- Unified power-quality conditioner (MC-UPQC)

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**SOFTWARE:** MATLAB/SIMULINK

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**BLOCK DIAGRAM:**

Fig.1.The single line diagram of conventional MC-UPQC

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** ****EXPECTED SIMULATION RESULTS:**

Fig. 2.a and b. the phase bus voltage, VS1 and load voltage VL1

Fig. 3.c and d. the phase bus voltage, VS2 and load voltage VL2

Fig.4.a & b. the phase Source Current, IS1 and Load CurrentIL1

Fig. 5 and 6 .a, b and c. The phase bus voltage, injected voltage and load Voltages

Fig. 7.a, b and c. The phase Source Currents (IS1), load Currents (IL1) and DC Capacitor Voltage(VDC).

Fig. 8.a, b, c, d, e and f. the phase bus voltage (VS1), load Voltages (VL1), load Voltages (VL2), the phase source currents (IS1), load Currents (IL1) and DC Capacitor Voltage (VDC).

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**CONCLUSION:**

In this paper the SRF Based control MC-UPQC for regulates of load voltage and load current in adjacent parallel feeder has been proposed and compared to a conventional MC-UPQC, the proposed control topology is capable of fully protecting critical and sensitive loads against sudden changing loads, voltage sag/ swells, and fault interruption in two-feeder distribution systems. The performance of the SRF based MC-UPQC is tested under various disturbance conditions.

**REFERENCES:**

- G. Hingorani “Introducing custom power,”
*IEEE spectrum*, vol.32, June 1995, pp. 41-48. - Ray Arnold “Solutions to Power Quality Problems” power engineering Journal, Volume 15; Issue: 2 April 2001, pp: 65-73.
- John Stones and Alan Collision “Introduction to Power Quality” power engineering journal, Volume 15; Issue 2, April 2001, pp: 58- 64.
- Fujita and H. Akagi, “The unified power quality conditioner: The integration of series and shunt active filter,”
*IEEE Trans. Power Electron.*, vol. 13, no. 2, pp. 315–322, Mar. 1998.. - Gyugyi, C. D. Schauder, S. L. Williams, T. R. Rietman, D. R. To rjerson, and A. Edris, “The unified power flow controller: A new approach to power transmission control,”
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