- The DANA weather phenomenon, which can produce intense storms and heavy rain in the Mediterranean, has caused significant flooding of both rooftop and utility-scale PV systems in the Valencian Community and Castilla-La Mancha in Spain.
Water exposure can lead to serious consequences for electrical devices such as inverters and batteries. It can cause short circuits, as water acts as a conductor that bridges circuits. Even after drying, water residues can lead to corrosion in sensitive electronic components.
The insulation of cables and components can also be damaged by water contact and abrasion caused by debris. This damage can reduce system performance or result in complete failure.
In addition, water damage can compromise electrical protections, creating safety risks. Furthermore, it can erode the soil around a structure’s anchoring piles, reducing their grip on the ground.
Rooftop recommendations
Choosing the right installation site is crucial to prevent damage from flooding in rooftop PV installations. Never install inverters and batteries in areas prone to flooding. Along with structural precautions, implementing technical safety measures is also advisable. Special FI switches, or residual current circuit breakers, can automatically interrupt the power supply upon water contact, minimizing the risk of short circuits and electric shocks.
Image: Geração Própria
If a system has already come into contact with water, avoid walking through flooded areas with electrical equipment due to the risk of electric shock. When flooding is imminent, shut down PV systems as a precaution. Qualified electricians or installers should inspect systems after floods. It is also wise to photograph any damages for insurance purposes before cleaning begins.
Thoroughly dry all affected components, even if they are no longer in contact with water, and consider professional drying if there is any doubt. A specialist must inspect all system components after water exposure, and any damaged parts should be repaired or replaced. Systems should not be reactivated until specialists confirm their safety and functionality.
Ground-mounted systems
Prevention is crucial for ground-mounted PV plants, so it is important to assess locations for flood risk and carry out necessary civil works based on hydrological studies.
In Spain, the Ministry for Ecological Transition and Demographic Challenge has created flood-risk maps for reference.
Even if a low-risk site is selected, severe weather phenomena such as DANA can overwhelm the absorption capacity of soil and drainage systems, leading to the accumulation of stagnant water.
Asier Ukar, head of Kiwa PI Berlin in Spain, noted the importance of conducting environmental and hydrological studies to mitigate damage.
“In theory, PV plants should be located in low-risk areas,” Ukar told pv magazine. “In fact, insurance companies are increasingly setting conditions to ensure coverage, as is the case with the impact of hail or snow, extreme phenomena that are increasingly common in other geographies such as the United States.”
Civil works, including the installation of drainage systems and the elevation of substations and transformation centers, can prevent significant issues.
“If all this is ignored, the disaster can be huge,” said Ukar. “Specifically, the piles, the wiring or the electronic devices of the medium voltage stations can be seriously affected.”
Additional measures may involve extra costs in areas where cold snaps are frequent. Although these measures drive up capital expenses, they can be worthwhile. Such measures include building dams to divert riverbeds, raising the height of ground modules, constructing roads with side slopes to facilitate water evacuation, and elevating string boxes off the ground.
“To raise the modules, you have to dig deeper and use more material, and apart from all that there is the civil work, which can be very expensive, but depending on the location, the cost could be worth it,” said Ukar.
He added that it is important to turn off all equipment if a flood has already occurred and to contact one’s insurance company. After an installation dries, one should gradually reconnect the affected areas following the corrective action manuals established by the operations and maintenance (O&M) company and the plant owner.
In particularly serious situations, it is likely that a plant will need to be inspected in its entirety, with a focus on electrical safety.
“If the inspections are done well and precautions have been taken, it is possible that installations affected by flooding continue to operate without complications,” said Ukar.
Author: Pilar Sánchez Molina
This article was originally published in pv magazine and is republished with permission.
