Changes in Fault current Levels at distribution network

8/10/2019 Changes in Fault current Levels at distribution network

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Outline

IntroductionBackground InformationMethodologySimulation Results

ConclusionReferences


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Introduction

Renewable embedded generation is known to createreverse power flow issues in a distribution network.Using MATLAB/Simulink, simulations could be madeto determine the effect of reverse power flow on faultcurrent levels in a distribution network.


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Background InformationGrowing demand for renewable energy.Reason:

Increase in cost of generating energyRenewable energy sources getting cheaper and easilyaccessible

Introduction of feed-in tariff by the governmentRenewed interest in embedded generation


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Embedded generation or distributed generation :Generation units with a maximum capacity of 50 to100 MW, usually connected to the distribution

network and neither centrally planned nor dispatched.Integral part of early power system networks when DCpower supply is still used.Phased out with the introduction of AC supply,centralized grid and generation in bulk


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In Malaysia, climate condition makes it ideal for PVSolar.Solar Irradiation: 800 1000 W/m 2

Ambient temperature: up to 40 CHowever, with a tropical climate of uncertain rain andcloud, shadows on PV Solar panels creates a significantdrop in PV Solar output.

Frequent fluctuations and unreliable supply.


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Disadvantages of embedded generation:Reverse power flowDisruption in the coordination of protection system

Voltage swellSystem Islanding


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Current sources of the load block


10/21Calculation blocks for the current sources


11/21Test system model


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Simulation ResultTest system is simulated for a period of 24 hours.

Faults are created at 6 different times:6 a.m.9 a.m.12 p.m.

3 p.m.6 p.m.9 p.m.


13/21Power flow graph


14/21Current magnitude without PV


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Current magnitude with PV


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Test system model is expanded to 5 loads and 2 PVs.System is fitted with overcurrent relay protection toobserve tripping time of each relay.

Fault is located at Load E.Simulation is done for 20 seconds with the faultstarting at 5 seconds after the simulation starts.Test system is equivalent to the system at 12 p.m.


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Expanded test system network


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Overcurrent relay tripping time for ground fault


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Overcurrent relay tripping time for high

impedance fault


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Conclusion

Reverse power flow causes significant drop in faultcurrent flowing through a section of the line.

Overcurrent relays will not work properly in the eventof a high impedance fault.There is a need to revise current protection systems toinclude protection during reverse power flowconditions when supporting systems with highpenetration of PV.


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References[1] Driesen, J., Belmans, R., "Distributed Generation: Challenges and Possible Solutions," Power Engineering

Society General Meeting, vol. IEEE, p. 8, 2006.[2] Rahman, H. A., K. M. Nor, M. Y. Hassan, S. Thanakodi, M. S. Majid, F. Hussin, "Modeling and simulation of

grid connected Photovoltaic System for Malaysian climate using Matlab/Simulink," Power and Energy (PECon),

2010 IEEE International Conference, vol. IEEE, pp. 935-940, 2010.[3] Phimmasone, V.; Kondo, Y.; Kamejima, T.; Miyatake, M., "Evaluation of extracted energy from PV with PSO-

based MPPT against various types of solar irradiation changes," Electrical Machines and Systems (ICEMS), 2010International Conference on, p. 2010, 487-492.

[4] Kai Yang, Walid, A., "Outage-storage tradeoff in smart grid networks with renewable energy sources," 2012International Conference on Computing, Networking and Communication, 2012.

[5] Cipcigan, L.M., Taylor, P.C., "Investigation of the reverse power flow requirements of high penetration of small-

scale embedded generation," IET Journal of Renewable Power Generation, vol. 1, no. 3, 2007.[6] M. Geidl, "Protection of Power Systems with Distributed Generation: State of the Art," Swiss Federal Institute

of Technology (ETH) Zurich, 20 July 2005.[7] M. T. Doyle, "Reviewing the impacts of distributed generation on distribution system protection," Power

Engineering Society Summer Meeting, vol. 1, no. IEEE, pp. 103-105, 2002.

[8] Girgis, Adly, and Sukumar Brahma, "Effect of distributed generation on protective device coordination indistribution system," Power Engineering, 2001, LESCOPE'01, 2001 Large ENgineering Systems COnference, vol.

IEEE, pp. 115-119, 2001.[9] Boljevic, S.; Conlon, M. F., "Fault Current Level Issues for Urban Distribution Network with High Penetration

of Distributed Generation," Energy Market, 2009. EEM 2009. 6th International Conference on the European,pp. 1-6, 2009.

[10] Massoud, A.M.; Ahmed, S.; Finney, S.J.; Williams, B.W., "Inverter-Based Versus Synchronous-Based DistributedGeneration; Fault Current Limitation and Protection Issues," Energy Conversion Congress and Exposition(ECCE), 2010 IEEE, pp. 58-63, 2010.

[11] Network Protection & Automation Guide, Levallois-Perret: ALSTOM, 2002.

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Changes in Fault current Levels at distribution network