Chandima Gomes, PhD Professor of HV Engineering University of the Witwatersrand Chandima.gomes@wits.ac.za

PVpanel

Junc,onbox

InverterTransformer Grid

!  PV installation without external LPS

!  PV installation with external LPS when separation distance is kept

!  PV installation with external LPS when separation distance is not kept

Surge Protection of Photovoltaic Systems

!  PV installation without external LPS

1 SPD as required according to MS IEC 62305-4:20072 SPD Class II 3 SPD PV Class II 4 SPD PV Class II

!  PV installation with external LPS when separation distance is kept

1 SPD as required according to MS IEC 62305-4:20072 SPD Class II 3 SPD PV Class II 4 SPD PV Class II 5 Separation distance is kept or isolated LPS6 Air termination system7 Down conductor

!  PV installation with external LPS when separation distance is not kept

1 SPD as required according to MS IEC 62305-4:20072 SPD Class I3 SPD PV Class I 4 SPD PV Class I 5 Equipotential bounding (separation distance is not kept = Non-isolated LPS)6 Air termination system7 Down conductor

WorkbyHongKongPolytechnicUniversityGroup

Heat dissipated in a shaded cell caused the module to crack.

1/200μs@100kA

Induced voltage between negative/positive cables and the ground terminal.

SPDswithUpvalueof2.2kV

Thepeakvoltageacrosstheposi,veandnega,veterminalsofthePVpaneloutputwasincreasedby40%-60%

xx

Theinducedvoltagewasdroppedto5%-7%oftheearliervalue

For roof top PV systems where the panel frame is connectedseparatelytoadifferentground.

Eg.Steelreinforcementstructureofthebuilding

The voltage across the posi,ve and nega,ve terminals could be100kV–200kVbasedonthegroundresistanceoftheLPS

SelecttheUpappropriately

Insertaline-to-lineSPDaswell

Largecableloopduetotheinterconnec,oncablesleavingtheJ-Boxesandconnec,ngtothepowerinverter

Reduc,onofthecableloopduetotheinterconnec,oncablesconnec,ngtothepowerinverterbyrou,ngprecau,ons

Interconnection cables connecting to the power inverter by using shielded cables bonded at both ends to the same equipotential bonding bar

Reduction of the cable loop due to the interconnection cables connected to the power inverter by the adoption of SPDs

ItisrecommendedtoconductthermalimagingofthepanelaVeraknownlightningstrikeintothesite

Thanks