anti islanding technology(passive)

3/31/20171

ELECTRICAL AND ELECTRONICS

DEPARTMENT

AMRITA SCHOOL OF ENGINEERING,

ETTIMADAIPRESENTED BY:

MINU YACOB-RET16010

Anti-islanding Detection for Grid

Connected Solar Photovoltaic system

GUIDED BY,

Dr A

VIJAYAKUMARI

ISLANDING

The continued operation of a Distributed generator (DG)

even when the electric utility is absent,

- Unintentional islanding

- Intentional islanding

Effect of Islanding

- hazard for utility line-workers.

- DG being a limited capacity source – entire utility

load come on it - The DG protection will be triggered

- Reclosing into an island may result in damaging

the DG equipment, because of out of-phase

closure.3/31/20172

ANTI-ISLANDING GRID

STANDARDS

IEEE 1547-2003: 4.4.1-For an unintentional island in

which the DR energizes a portion of the Area EPS through

the PCC, the DR interconnection system shall detect the

island and cease to energize the Area EPS within two

seconds of the formation of an island. [1]

The IEEE Std. 1547 and UL 1741 provide thresholds on

the amount of acceptable voltage and frequency deviation.

Thresholds on voltage deviations are in the range of 88% to

110% of the nominal voltage value [2].

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ANTI-ISLANDING TECHNIQUES

3/31/20174 source-[4]

FIG:1

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COMPARISON OF ANTI-ISLANDING

TECHNIQUES• DETECTION TIME

• PARAMETERS TO BE MONITORED

• NON DETECTION ZONE

The NDZ is the range of local loads for which the

islanding prevention method can be made to fail to detect

islanding.

When the utility disconnects, if Pload =PDG, change in the

amplitude or frequency of voltage will be insufficient to

activate any of the standard over/under voltage or

frequency protection devices.

PASSIVE ANTI ISLANDING DETECTION

• Active power is directly proportional to the

voltage.

• When PDG > Pload there is an increase of the

amplitude of the voltage

• if PDG < Pload there is a decrease of the

amplitude of voltage

Pload =PDG+∆P

Qload = QDG +∆Q

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Source-[5]FIG-2

OVER-UNDER VOLTAGE DETECTION

METHOD

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IMPLEMENTATION OF OVER-UNDER VOLTAGE

DETECTION METHOD

CASE 1- 5kW Load(PDG>Pload)

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Power rating of pv system-59.5 kW

Power rating of the load-5kW

Circuit Breaker opening time-.6s to .8s

CASE 1- ACTIVE POWER FLOW

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VOLTAGE AND CURRENT AT PCC

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Case 2-120kW LOAD(PDG<Pload)

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Power rating of pv system-59.5 kW

Power rating of the load-120kW

Circuit Breaker opening time-.6s to .8s

CASE 2-ACTIVE POWER FLOW

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Case 2– VOLTAGE AND CURRENT

AT PCC

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59.2 kW LOAD – VOLTAGE AND

CURRENT AT PCC

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CONCLUSION

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OV/UV passive islanding detection method failed to

detect islanding when the Pload matches the PDG.

The chances of detection of islanding using OV

method is less compared to UV because the change in

voltage during islanding is less.

REFERENCE [1] IEEE Std 1547-2003, Standard for Interconnecting

Distributed Resources with Electric Power Systems,

IEEE, 2003.

[2] Static inverter and charge controllers for use in

photovoltaic systems , UL 1741, Underwriters

Laboratories, Inc., 2001, Std. UL . stems

[3] Francesco De Mango', Marco Liserre, Antonio

Dell'Aquila and Alberto Pigazo Overview of Anti-

Islanding Algorithms for PV Systems. Part I: Passive

Methods. 2006 IEEE.

[4] K. O. Samaroo, “Methodology of Selection, Setting

and Analysis ofAnti-Islanding Protection for

Distribution Generation System,”University Of

Guyana, Department of Electrical Engineering, 2012.3/31/201716

3/31/201717

[5] M. Hanif, M. Basu ,K.Gaughan ‘A Discussion

of Anti-islanding Protection Schemes

Incorporated in a Inverter Based DG’ 2011 IEEE