Page 35 - Energize March 2021

TECHNICAL

DEHN protects wind and

PV installations

To address the environmental damage done by burning fossil fuels to generate electricity, a steady shift
towards more environmentally friendly and sustainable methods of generation is taking place. DEHN
provides new technology to protect these installations from lightning strikes.

he world’s reliance on fossil fuels for Plainly stated, the financial consequences of not having a lightning and surge protection
energy has had major geopolitical solution far outweigh the cost of completing a risk assessment and getting the right protection.
Timplications since humans first Since the investment outlay is high, operators need to maintain permanent system
started burning coal thousands of years availability to ensure profitability of the plant. As an industry expert for power distribution
ago. The amount of carbon dioxide (CO ) grids, DEHN offers special protection solutions, ranging from power generation to power
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in the atmosphere reached record levels in distribution with a focus on PV systems and wind turbines. Our interaction starts off with a
2020, hitting 417 parts per million in May. comprehensive risk assessment to determine the level of risk, informing how much external
Fortunately, developments in lightning protection is required.
technology have allowed us to start The lightning-related risk is calculated according to the The South African National
leveraging on smarter, cleaner energy Standard PV lightning standard (IEC/SANS 61643-32), which is the norm to be observed
sources to power our homes and for protecting PV systems in the event of a lightning strike. The standard states that surge
businesses. Solar and wind energy have arresters are mandatory, along with an external Lightning Protection System (LPS) for
been areas of increasing interest for PV installations. This risk analysis completed by DEHN provides the basis for planning a
countries across the globe. comprehensive lightning protection solution. This is all done with the goal of protecting the
The favourable weather conditions in workers on the plant, the assets as well as the actual panels along with all the components, all
many countries across the African continent while ensuring high system availability.
make the usage of solar and wind energy
viable. Traditionally reliant on hydropower A lightning protection system for free field systems and solar parks typically has two main goals:
and coal, the continent is steadily turning • Protection of the power plant area from lightning-related damage of the modules,
to solar photovoltaics (PV) to bolster inverters, and
energy security to facilitate rapid economic • Monitoring systems from the effects of electromagnetic impulses
growth in a sustainable manner. Setting up
a solar park is extremely capital intensive; A suitable lightning protection system consists of external and internal lightning protection.
therefore, investors need to ensure that their External lightning protection includes air-termination systems and down conductors
financial interests are protected, so that which discharge the lightning current via defined paths to the ground. To ensure internal
they can shorten the time to profitability. protection, it is recommended to use surge protective devices (SPDs) in all areas that are
PV systems, by nature, are extremely deemed to be at risk.
exposed and therefore especially For a more proactive approach, DEHNdetect can reliably detect lightning events,
vulnerable to direct and indirect damage preventing losses resulting from system downtime and expensive repair work, specifically on
from lightning strikes. Climate change wind turbines.
has also brought about new challenges: The revised standard IEC 61400-24 (July 2019) Wind turbines Part 24: Lightning protection
warmer conditions have contributed to recommends the installation of measuring systems which can also measure long stroke
a global increase in the lightning flash currents to determine the intensity of lightning strikes. Damage resulting from a lightning
density, making it even more vital to strike is not always evident and does not necessarily lead to the immediate failure of a turbine.
invest in Lightning Protection Systems. In As a result, lightning events often remain undetected.
fact, South Africa has a particularly high Especially in the case of upward flashes the initial long stroke current flowing is a few
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lightning density (strikes/km ). hundred Ampere and can be the main cause of melting, e.g., on the receptors of rotor blades.
Lightning strikes and surges often lead The resulting subsequent damage may be severe.
to the destruction of system parts such as DEHNdetect is a lightning current measuring system for detecting lightning events.
modules, inverters, and monitoring systems, It has been designed to register these long stroke currents on wind turbines, as well as
which are costly to repair, and even more impulse current, to prevent the need for expensive maintenance work and long downtimes.
costly to replace. Lightning is a common DEHNdetect can also be equipped with optional rotor blade detection.
cause of failures in PV and wind-electric The system keeps you informed about what is going in your wind turbines, whether this is
systems. A damaging surge can occur for an individual turbine or an entire wind park, giving you continual data on the condition of
from lightning that strikes a long distance your components. This includes the option of setting up push messages that would be sent
from the system, or even between clouds. directly to your smartphone or tablet. The system allows you to invest in availability and make
But most lightning damage is preventable. your wind turbines a reliable source of power, both now and in the future. n

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