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© 2016 DEHN + SÖHNE / protected by ISO 16016

Risk Mitigation

through Lightning Protection


Risk Mitigation through Protection

Agenda

Damages to PV Systems

Standards and Norms

Lightning Protection Concepts

Video: Isolated Lightning Protection System

Questions & Answers



PV Modules Damage

Combiner Box Damage

Inverter Damage

Communication System Damage

Sensitive Equipment Damage (Trackers, Security Systems)

Damage Statistics



PV Modules Damage

source: Solarzentrum Oberland GmbH

Arcing/Short-circuiting of PV Modules due to lightning



PV Modules Damage

Broken glasses, Burned/Melted DC Cables and Combiner Box

Defective bypass diodes



Combiner Box Damage

source: R. Schüngel, Munich

Melted Combiner Boxes and DC Cables

due to Short-Circuit currents

Breakdown of sensitive and or monitoring

components inside Combiner Box



Inverter Damage

Internal component failure inside an Inverter (Central & String)



Communication System Damage

Holes in the Cable insulation

Data cables causing failure of Switches, PLC’s etc…



Reasons why a LPS is required by Owners/Insurers

SAPVIA - Risk Mitigation through Protection 9

DETAIL DESCRIPTION

Investment (Capital) > R Millions/Billions

Life time of the plant and equipment > 20 years

Return on Investment (Business Model) Linked to kWh output

Downtime due to damaged components > Time (hrs/days)

Insurance Access payable with every claim > R 500 k

Insurance premium hikes due to claims TBD

Breakdown of equipment due to inherent effects > R xxx

Degradation of equipment and components > R xxx

Lightning and surge protection measures are essential!



Damage Statistics – Comparison (Frequency of Occurence)

Causes of damage (2003-2013)

Evaluation Mannheimer Versicherung

Causes of damage (2005-2014)

Evaluation Bayerischer Versicherungsverband

source: Bayerischer Versicherungsverband 2014 source: Mannheimer Versicherung 2014

South Africa has on average 10 times more lightning density (strikes/km2)



Damage Statistics – Damages Costs

source: Bayerischer Versicherungsverband 2014

Costs of Damages (2005-2014)

Evaluation Bayerischer Versicherungsverband



Frequency of the risk of a Lightning Strike in South Africa


ITEM DETAIL

Output (MWp) 75

Modules > 600k

Area (km2) 3

Lightning Density (strikes/km2) 5.8

Total Direct Lightning (year) 17.4

Rain Season (months) 5 – 6

Total Strikes in Rain Season (p/month) 3 – 3.5

Total Cost of the Plant R 2 Bil

Total Loss as a result of Lightning

(year) without Protection

R 20 Mil

Lightning and surge protection measures are essential!


Standards & Norms

SANS 10313: 2012

SANS (IEC) 62305: 2010-12

EN 62305: 2009-10 (VDE 0185-305: 2012)

SANS 10142 – Part 1 (Coming soon)


Standards and Norms

SANS 10313:2012 & SANS (IEC) 62305:2010-12


Standards and Norms

EN 62305: 2009-10 (VDE 0185-305: 2012)


Standards and Norms

DIN EN 62305-3, suppl. 5 (VDE 0185-305-3 suppl. 5):2009-10

(translation)

The required class of LPS (I-IV) is determined by means of a risk analysis

according to DIN EN 62305-2 (VDE 0185-305-2). The class of LPS can

also be defined in consultation with the planner, owner and/or user.

Regulatory requirements frequently call for lightning protection

measures for this type of structure to prevent fire and/or to protect

persons.

If possible, a lightning protection system should be preferred which is

not directly connected to the photovoltaic power supply system and

where adequate separation distances are kept.


Standards and Norms

IEC 62305:2010-2012, Part 1

A lightning protection system consists of an external and internal lightning protection system.

Functions of an external lightning protection system:

Interception of direct lightning strikes by means of an air-termination system

Conducting the lightning current to earth by means of a down conductor

Distribution of the lightning current in the earth by means of an earth-termination system

Functions of an internal lightning protection system:

Prevention of dangerous sparking in the structure by establishing equipotential bonding or keeping a separation distance between the components of the lightning protection system and other conductive elements in the structure.


Standards and Norms

DIN EN 62305-3 suppl. 5 (VDE 0185-305-3 suppl. 5):2009-10

(translation)

5.2 External lightning protection

Based on the DIN EN 62305-3 (VDE 0185-305-3) lightning protection

standard, roof-mounted photovoltaic power supply systems should be

protected against direct lightning strikes by means of isolated air-

termination systems, as far as practicable.

NOTE If a photovoltaic power supply system is newly installed

on a structure, the existing electrical installation may have

to be adapted.


Standards and Norms


(translation)

5.3 Down-conductor systems

5.3.1 General

NOTE 2 The installation of as many down-conductors as possible, at

equal spacing around the perimeter interconnected by ring conductors,

reduces the probability of dangerous sparking and facilitates the

protection of internal installations (see IEC 62305-4).

This condition is fulfilled in metal framework structures and in reinforced

concrete structures in which the interconnected steel is electrically

continuous.

Typical values of the preferred distance between down-conductors are

given in Table 4.


Standards and Norms

IEC 62305:2010-2012, Part 3

5.4 Earth-termination system

5.4.1 General

When dealing with the dispersion of the lightning current (high

frequency behaviour) into the ground, whilst minimizing any potentially

dangerous overvoltages, the shape and dimensions of the earth-

termination system are the important criteria.

From the viewpoint of lightning protection, a single integrated structure

earth-termination system is preferable and is suitable for all purposes

In general, a low earthing resistance is recommended. Earth-termination

shall be bonded in accordance with the requirements of 6.2.


Standards and Norms


(translation)

4.4 Lightning current distribution in a ground-mounted PV system

Depending on the relevant class of LPS, the type of earth-termination system

and the soil resistivity, SPDs with a lightning current discharge capacity of a

some kA are sufficient for ground-mounted PV systems.

The sample calculations are based on a mesh size of 20 m x 20 m. In case of

larger mesh sizes, it is to be expected that higher partial lightning currents flow

via the d.c. SPDs.


Standards and Norms


(translation)

5.6 Selection of surge protective devices

5.6.2 Type 1 surge protective device, lightning current carrying capability

It is recommended to use Type 1 surge protective devices on the d.c.

side of photovoltaic power supply systems, if

an external lightning protection system is installed and

the required separation distance from elements of the

photovoltaic power supply system is not kept.


Standards and Norms


(translation)

5.6 Selection of surge protective devices

5.6.1 General

Surge protective devices for the d.c. side must be chosen in such a way

that they enter a safe state even in case of a short-circuit without

presenting a risk of fire resulting from overload and arc formation.

The manufacturer of the surge protective devices provides evidence that

the switching device integrated in the surge protective device has the

switching capacity required for the conditions at the place of installation.


…enter a safe state even in case of a short-circuit without

presenting a risk of fire

with Short-Circuit Interrupt without Short-Circuit Interrupt

Video “Disconnection without SCI“


Lightning Protection Concepts

PV Systems with BONDED lightning protection

PV Systems with ISOLATED lightning protection


LIGHTNING PROTECTION CONCEPTS

PV system with BONDED external lightning protection system

`


Derated Type1+2

Type 1+2



PV system with BONDED external lightning protection system


Type 1+2



PV system with ISOLATED external lightning protection system


Type 2

Type 2



PV system with ISOLATED external lightning protection system


Type 2

© 2016 DEHN + SÖHNE / protected by ISO 16016 SAPVIA - Risk Mitigation through Protection

DEHNconcept

Risk Assessments

Detailed Design of LPS & Earthing Systems


PV system with

ISOLATED external LPS



Questions

SAPVIA - Risk Mitigation through Protection

ALEXIS. W. BARWISE

Managing Director (B. Eng)

DEHN AFRICA (Pty) Ltd.

Tel. +27 11 704 1487

[email protected]

www.dehn-africa.com

32

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