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Thursday, 10 August 2017

Mitigation of Voltage and Current Variations Due To Three Phase Fault in a Single machine system Using Distributed Power Flow Controller

The Power quality issues like voltage variations and current variations presented in the electrical networks are due to the consumer’s utilities. Which are non – linear in nature. These non – linear loads inject increased flow of currents and reduced voltages with distortions. These voltage and current variations cause adverse effect on the consumer utilities. To overcome this problem we are using a modern Flexible Alternating Current Transmission System controller i.e. distributed power flow controller. This controller is also similar to any other series and shunt controllers like UPFC. In the present controller i.e. in DPFC, the common Dc link capacitor presented in UPFC is eliminated and three single phase converters are used in place of three phase series converter. In this paper we have implemented DPFC for a single machine connected to a three phase load under three phase fault environment. Observed the voltage and current variation suppression in a significant way. The control circuit is formulated using shunt currents and series referral voltages. The entire system is designed and analyzed using MATLAB/SIMULINK.

1.      UPFC
2.      DPFC
3.      Decreased Voltage
4.      Increased current
5.      Power Quality



Fig. 1. Fundamental circuit of DPFC


Fig. 2. Simulation results during three phase fault condition.

Fig 3 Voltage drop mitigated during 0.1 to 0.12 sec due to DPFC system

Fig. 4. Simulation results during fault (current swell) condition.

Fig. 5. Simulation results for mitigation of current swell between 0.1 to 0.12 sec using DPFC system.

Fig. 6. Simulation results for active and reactive powers.

Fig. 7. THD of load voltage without DPFC

Fig. 8. THD of load voltage with DPFC (pi controller)

In this paper we implemented a new concept for controlling power quality problems by Distributed Power Flow Controller device. The proposed concept of the DPFC approach is mathematically formulated and analyzed for voltage and current variations and their mitigations for a three phase source with linear load. The experimental results of DPFC shows the effectiveness of DPFC in power quality enhancement as compared to all other FACTS devices which are used for voltage drop mitigation process.

 [1] Y.-H. Song and A. Johns, ‘‘Flexible ac Transmission Systems (FACTS)’’, (IEE Power and Energy Series), vol. 30. London, U.K.: Institution of Electrical Engineers, 1999.
[2] N. G. Hingorani and L. Gyugyi, Understanding FACTS : Concepts and Technology of Flexible AC Transmission Systems. New York: IEEE Press, 2000.
[3] L. Gyugyi, C. D. Schauder, S. L.Williams, T. R. Rietman,D. R. Torgerson and A. Edris, ‘‘The unified power flow controller: Anewapproach to power transmission control,’’ IEEE Trans. Power Del., vol. 10, no. 2, pp. 1085---1097, Apr. 1995.
[4] A. A. Edris, ‘‘Proposed terms and definitions for flexible ac transmission system (facts),’’ IEEE Trans. Power Del., vol. 12, no. 4, pp. 1848---1853, Oct. 1997.
[5] K. K. Sen, ‘‘Sssc-static synchronous series compensator: Theory, modeling, and application,’’ IEEE Trans. Power Del., vol. 13, no. 1, pp. 241---246, Jan. 1998.