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Photovoltaic Overview

SURGE PROTECTION FOR PHOTOVOLTAIC INSTALLATIONS

Photovoltaic plants are often fastidious and cost intensive projects,

with a life duration expected for several decades.

Many manufacturers of Photovoltaic (PV) modules used to guarantee

them a life expectancy greater than 20 years, costs and investment

are calculated on this long period.

However these systems are often very exposed to lightning phenomena

which could drastically reduce the long operating duration required.

Several points must be considered in order to analyze the risk :

1. The larger the ﬁ eld of PV modules, the higher the risk to be

disturbed by lightning.

2. Direct effect (strike on the PV modules) and indirect effects (surge

voltages on PV modules and on the converters).

3. When the PV system is located in large industrial areas,

disturbances by switching surge voltages must be also considered.

4. The risk is in direct relation with the lightning strike density of the

area. Some calculations show that the life duration of the PV panels

will be lower than 8 years.

EFFICIENT LIGHTNING & SURGE PROTECTION

A professional approach to lightning and surge protection will

guarantee your Photovoltaic systems a long life. Some basic but

important points must be addressed in order to provide a high level of

reliability to your PV system.

Earthing and Bonding

All the metallic frames of the systems must be grounded in order to

achieve a global equipotentiality of the installation.

AC Distribution Panel

Protects all loads connected to the

facility’s main distribution panel

against transients originating

from the AC utility grid or internal

switching equipment.

Inverter : AC Output

Local protection in front of the

inverter to protect against threats

from the AC utility and generated

internally within the facility.

Inverter : Communications Output

Protects inverter, communication

equipment and PC workstations

against lightning induced

transients entering the system

via exposed sensor and

communication lines.

Inverter : DC input

Local protection in front of the

inverter to protect against lightning

induced transients originating

from the solar PV array.

Surge protection of PV modules

Protects PV modules, power

tracking and blocking diodes from

physical damage resulting from

lightning induced transients.

SURGE PROTECTION FOR SOLAR PV SYSTEM

Underground ducts

If possible, the connection line between PV modules and inverter

must be underground to limit the direct strike and coupling risks.

AC and DC Surge Protection

Surge Protection of both AC and DC lines must be provided.

In case of direct lightning exposure, the SPDs must be able to partially

conduct the lightning currents : Type 1 selection.

On the other hand, the SPD must operate on surge voltages (Type 2).

Do not forget

In order to achieve the best efﬁ ciency, surge protection on the other

types of conductors such as rotating motor power supply, probes,

transmission lines...must be considered.

SURGE PROTECTION FOR PV SYSTEM

SPDs must be ﬁ rst applied to protect the PV inverter, on its AC and

DC sides. Extra SPDs must also be used on the AC Distribution Panel

and close by the PV modules, especially if these ones are far from

the inverter.

The AC side of the installation must be protected by Type 1 or Type 2

AC power SPDs.

Because the DC side of the PV installation is speciﬁ c by its high DC

voltages (up to 1000 Vdc) and its low short-circuit, the SPDs used

must be especially designed for this application : CITEL DC surge

protectors are in compliance with the relevant test standards as

prEN50539-11 (Europe) or UTE C61-740-51 (France).

SPDs for DC side are available for Type 1+2 (DS60VGPV) and Type 2

(DS50VGPV and DS50PV) application. Operating voltages up to 1000

Vdc.

The VG versions allows total suppression of operating and leakage

current as well as improved life expectancy.

>10 m

KWh

SPD

Data

KWh

SPD

Data

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