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The recent floods in Spain have brought a topic of concern to the forefront. pv magazine looks at recommendations and precautions to be taken into account, as exposure to water of electrical devices such as inverters or battery packs can have serious consequences.
The DANA meteorological phenomenon, which can produce intense storms and heavy rains in the Mediterranean, has caused significant flooding in both rooftop and large-scale photovoltaic systems in the Valencian Community and Castilla-La Mancha in Spain.
Exposure to water can have serious consequences for electrical devices such as inverters and batteries. It can cause short circuits, as water acts as a conductor that links circuits together. Even after drying, water residue can cause corrosion on sensitive electronic components.
Cable and component insulation can also be damaged by contact with water and abrasion from debris. This damage can reduce system performance or lead to total failure.
Additionally, water damage can compromise electrical protections, creating safety risks. It can also erode the soil around a structures anchor piles, reducing their grip on the ground.
Recommendations for roofs
Choosing the right installation location is crucial to prevent flood damage to rooftop PV installations. Never install inverters and batteries in flood-prone areas. Along with structural precautions, it is also advisable to implement technical safety measures. Special FI switches, or residual current circuit breakers, can automatically interrupt the power supply upon contact with water, minimising the risk of short circuits and electric shocks.
If the system has already come into contact with water, it is important not to walk through flooded areas where electrical equipment is located, as there is a risk of death from electric shock.
When there is a risk of flooding, it is advisable to shut down the photovoltaic system as a precaution. When it comes to checking it, it is advisable to inform a qualified electrician or the installer of your photovoltaic system. Only specialists should check the system and put it back into operation after a flood.
It is also recommended to photograph any damage for insurance purposes before beginning any cleanup.
Even though they are no longer in contact with water, all affected components must be thoroughly dried. If in doubt, professional drying is recommended.
After contact with water, all system components must be inspected by a specialist. Damaged parts must be repaired or replaced.
Finally, the system should not be put into operation until a specialist has confirmed its safety and functionality.
Plants in soil
In the case of plants on the ground, prevention is the best option, so the most important measure is to assess whether the location presents a risk of flooding and undertake the relevant civil works based on the hydrological study.
In Spain, the Ministry for Ecological Transition and Demographic Challenge has created the Flood Hazard and Risk Maps, which can be consulted here.
However, despite having chosen a low-risk site, it can happen that a DANA such as the one that recently hit Spain, the capacity of the soil to absorb and the drainage systems to move water is overwhelmed, causing a large amount of stagnant water.
To mitigate damage, Asier Ukar, Head of Kiwa PI Berlin in Spain, points out the great importance of environmental and hydrological studies. “In theory, PV plants should be located in low-risk areas. In fact, insurance companies are increasingly setting conditions to ensure coverage, as is the case with the impact of hail or snow, increasingly frequent extreme phenomena that have hitherto been common in other geographies such as the United States,” he told pv magazine.
However, when it comes to undertaking civil works, some consequences can be prevented, such as implementing a drainage system or elevating the substation and transformation centres. “Specifically, the piles, wiring or electronic devices of medium voltage power stations can be seriously affected,” explains Ukar.
There are additional measures that would imply an extra cost for areas where cold drops begin to be less exceptional and that, although they increase the CAPEX expense, may end up being worth it, such as building dams to divert the riverbed, raising the height of the ground modules, building the roads with a slope to the sides to evacuate the water, and raising the string boxes off the ground. “To raise the modules you have to dig deeper and use more material (steel), and apart from all that there is the civil work, which can end up being very expensive, but depending on the location, the cost could be worth it,” he says.
If flooding has already occurred, the first step is to "turn off everything as much as possible, call the insurance company and, once the installation is dry, gradually reconnect the affected areas according to the corrective action manuals, which should be defined by the O&M company and the plant owner in anticipation of these problems occurring," he explains.
Furthermore, in particularly serious situations, the plant may need to be inspected in its entirety following a scope similar to that given in the commissioning of a plant for the first time, with the main focus on electrical safety.
"If inspections are carried out properly and precautions are taken, it is possible for facilities affected by flooding to continue to operate without complications," concludes Asier Ukar. |
