Hurricane loss prevention for solar PV installations

When a hurricane is likely to occur effective preparations can mitigate damage, prevent loss, and limit downtime. Hartford Steam Boiler (HSB) recommends that the following steps be taken prior to a hurricane event:

  • Store modules. All tracking systems should be stored in a safe, neutral position to reduce wind drag. Follow all racking manufacturers’ recommendations for stowing and securing modules.
  • Take plant off-line. To reduce loss potential during and following a hurricane it’s safe practice to de-energize the plant as much as possible. Electrical separation between components via breakers and disconnects may help prevent electrical losses from compounding. Shutting off all breakers at inverters, trackers, and combiner boxes will provide separation between these components. Remove the plant from the grid at the point of interconnect or in the switchyard. This will help to mitigate losses caused by grid disruptions that will happen during the hurricane.
  • Ensure watertight integrity of components. Hurricane winds will blow rain into every possible crack or opening. Ensure that all components and cabinets are shut and well-sealed. Doors to all electrical cabinets should be watertight and locked to maintain their integrity during the storm.
  • Tighten fasteners and clamps. Any loose fasteners, clamps, or wiring should be secured before the storm arrives. This is especially important in areas of the plant that are undergoing maintenance or repairs and may be compromised.
  • Check surroundings for any loose objects. Strong winds will pick up loose objects and cause damages. Tools, buckets, spare modules or other parts should be well secured or removed from the site. Loose pallets, wood, tree limbs, and other moveable materials should be removed or secured. If loose materials can’t be removed or secured then moving them to the downwind side of the facility will help to prevent losses from occurring.
  • Check drainage ditches. Ensure drainage systems are free of debris and growth to effectively remove water from the plant. If time permits, construct flood barriers with sandbags or other materials. Even if these do not hold back floodwaters, they may resist flood currents sufficiently to prevent undermining and erosion of racking system footings. De-energize all electrical circuits prior to flooding.

When a storm is imminent

“Personnel before property” is the rule when a storm is about to strike. Never yield to the temptation to continue preparatory work if there is a possibility that anyone could be jeopardized by the arrival of the storm. Once a hurricane arrives, unpredictable dangers will happen. All personnel should obey evacuation orders and move to safety in advance of the storm and prior to the rise of any floodwater.

In the aftermath

Remember, modules will produce power when exposed to sunlight even when disconnected. If modules or wiring are sitting in water there is a heightened risk of electrocution. For machinery and equipment, there is usually a significant opportunity to minimize damage at this stage. Proper cleaning and drying will often avoid serious damage and help to restore the premises to operation more quickly and at a lower cost.


The risk does not recede with the water

If your equipment, machinery or electrical systems have been exposed to flood waters, you risk their loss even when the water level has dropped. Equipment and machinery may have water, silt or other contaminants within them. Your equipment could be damaged or destroyed if you attempt to start or test it without adequate cleaning and preparation for operation. DO NOT ATTEMPT TO OPERATE OR TEST YOUR EQUIPMENT WITHOUT PROPERLY RESTORING IT. Even when your equipment’s exterior appears normal, residual moisture and contaminants can lead to permanent damage.

Dry and clean before using

The following summarizes the steps to prepare your equipment for operation. Most actions involve careful draining, drying, and cleaning of equipment before attempting to start or energize it. Taking these precautions now can help you to avoid a major equipment failure and enable you to restore vital operations sooner.

Electrical equipment

DO NOT ENERGIZE equipment that has been flooded until properly inspected, cleaned, dried out, and insulation has been tested. This includes enclosures, bus ducts, conduit, and cables. Application of power to wet circuits will usually result in serious damage that will require repair or replacement. It is usually better to spend the necessary drying time than to risk destruction of the equipment.

  • Windings in electric machinery should not be dried at temperatures exceeding the rating of its insulation system. In general, a maximum temperature of 194 degrees F or 90 degrees C may be used. Check with the manufacturer for equipment specific information and recommendations.
  • Dry type transformers should be cleaned and thoroughly dried as described for windings.
  • Oil filled transformers should be thoroughly inspected for damage including the insulation bushing and oil samples should be drawn from the tank’s top and bottom for analysis. Examine the sample for free moisture in the form of moisture droplets or a cloudy appearance. The laboratory should be instructed to include a Karl Fischer test for dissolved water content. Maximum water content for equipment rated >= 69kv is 25 ppm and equipment rated at <69kv is 35 ppm. If water is found in the oil, the oil charge must be dehydrated by a competent service firm.
  • Circuit boards that have been immersed can sometimes be salvaged, if they were not energized at the time of immersion, and further provided that water sensitive components are not mounted to them. This can be done by carefully washing the individual boards in pure water and thoroughly drying before energizing. Other components, especially those affected by salt or brackish water, may also benefit from a freshwater rinse and cleaning. Never use high-pressure water for this purpose.

It is our hope that you can quickly recover from a hurricane event with no loss to property and with as little downtime as possible. HSB has professional resources to help if you have any questions during this time. Please ensure that all personnel remains safe during and after the storm.


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© 2021 The Hartford Steam Boiler Inspection and Insurance Company. All rights reserved. This article is for informational purposes only and is not intended to convey or constitute legal advice. HSB makes no warranties or representations as to the accuracy or completeness of the content herein. Under no circumstances shall HSB or any party involved in creating or delivering this article be liable to you for any loss or damage that results from the use of the information contained herein. Except as otherwise expressly permitted by HSB in writing, no portion of this article may be reproduced, copied, or distributed in any way. This article does not modify or invalidate any of the provisions, exclusions, terms or conditions of the applicable policy and endorsements. For specific terms and conditions, please refer to the applicable endorsement form.

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