- Photovoltaic
- PVT110 (S/N: TF21-UP)
- PVT115 (S/N: TF51-UP)
- PVT117 (S/N: TF71-UP)
- PVT120 (S/N: GH81-UP; TF81-UP)
- PVT115 (S/N: TF51-UP)
Introduction
Cat® PVT110, PVT115, PVT117, and PVT120 PhotoVoltaic Modules are frameless and do not require cleaning as installed. Installed modules may collect a light layer of dust and/or dirt over time. For many installations, rainfall should be sufficient to remove any lighter soiling. In locations with heavy soiling, properly timed module cleaning can improve energy yields.
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.
Safety Section
Cleaning activities create risk of damage to the modules and array components, as well as the potential for electric shock
Only properly trained personnel who understand the risks of applying water to electrical components should clean modules. Trained personnel shall wear appropriate electrically insulating Personal Protective Equipment (PPE) during cleaning, inspection operations, or when working near modules.
Professional cleaning services trained to work on live electrical systems are available for hire.
The module encapsulating material and glass provide protection from electrical shock hazard when intact. However, when cracked or chipped, the module’s integrity is compromised (i.e., potential loss of electrical insulating properties,) thereby creating an electrical shock hazard.
Note: Cracked or broken modules represent a shock hazard due to leakage currents, and the risk of shock is increased when modules are wet. Before cleaning, thoroughly inspect modules for cracks, damage, and loose connections.
Note: The voltage and current present in an array during daylight hours are sufficient to cause a lethal electrical shock.
Acceptable module cleaning methods include spraying the modules with low-pressure water that is closely matched in temperature to the temperature of the module or to use a dry brushing technique. The following guidelines minimize impact to plant power generation, reduce safety hazards, and minimize risk of module damage.
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Contact with loose connectors can result in electrical shock and may cause injury or death. |
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Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility. |
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Before servicing/performing maintenance on the machine, electrical power must be physically disconnected; battery plugs must be disconnected from the batteries, or the trailing cable must be unplugged, and warning tags and padlocks shall be applied by a certified electrician. Certified electricians shall perform or direct any electrical work, including any energized testing, repair work in controllers, motors, or other approved compartments, and shall insure that all compartments are properly closed and inspected prior to re-energization. All applicable lock out and tag out procedures must be followed. |
General Cleaning Techniques for All Module Types
- Clean modules only when in open circuit and when modules are locked out from the load. The recommended time to clean modules is from dusk to dawn when production is not affected and risk of electrical shock hazard is minimized.
- To ensure warranty coverage, Cat must review and approve:
- Automated or motorized cleaning tools and methods.
- Cleaning fixtures or tools which are supported by or rest on modules.
- The ideal time for cleaning modules is during low light conditions when production is lowest.
Cleaning Techniques for Uncoated Modules
Wet Cleaning
- Fresh water (Total Dissolved Solids < 1500 mg/L) may be used to clean the modules. If needed, a mild, non-abrasive, non-caustic detergent with a final fresh water and detergent solution mix between 6.5 < pH < 8.5 at 25°C may be used.
- Water must be free of floating oil or other immiscible liquids, floating debris, excessive turbidity, and objectionable odors.
- When using water, Reverse Osmosis (RO) water provides the best results. When "RO" water is not available, tap water with low mineral content (total hardness < 75 mg/L) or deionized water may be used. Calcium should not exceed: 75 mg/ml.
- When using hard water (75 mg/L < total hardness < 180 mg/L), the water must be squeegeed off to prevent scale buildup.
- Chlorides should not exceed 250 mg/ml and water electrical conductivity should be < 250 mS/cm.
- Do not use abrasive cleaners or de-greasers on the module. Do not use cleaning solutions containing hydrochloric acid, D-Limonene, benzene, nitro-thinners, ammonia, or sodium hydroxide.
- Water pressure must not exceed
35 bar (508 psi) at the nozzle. Do not apply water that is more than 20°C warmer or colder than module surface temperature. - Do not spray pressurized water directly at sealed interfaces of module (junction box, edge seal, connectors). Do not brush or clean backside of module to avoid accidental stress to lead wires or junction box.
Dry or Brush Cleaning
- If excessive soiling is present, a non-conductive nylon or similar material brush, sponge, or other mild agitating method may be used with caution.
- Ensure brushes or agitating tools are not abrasive to glass, EPDM, silicone, aluminum, or steel.
- Ensure any brushes or agitating tools are constructed with non-conductive materials to minimize risk of electric shock.
Cleaning Techniques for Anti-Reflective Coated Modules
Wet Cleaning
- The wet spray cleaning techniques for uncoated modules detailed above may be used for anti-reflective coated modules.
- Wet contact cleaning, which includes any simultaneous combination of water and scrubbing/wiping the modules is prohibited for anti-reflective coated modules.
- Excessively soiled spots on modules (i.e. bird droppings) may be spot-cleaned with soft cloth or mop and water if necessary for localized cleaning only.
Dry Cleaning
- Dry cleaning of anti-reflective coated modules with soft cloths or mops is allowed up to six times annually. Examples of soft cloths or mops are shown in Illustration 1.
- Dry cleaning with anything other than soft cloths or mops is prohibited (i.e. bristle brushes, sponges, or squeegees).
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| Illustration 1 | g06360892 |
Module Shading
When module cell areas are shaded by cleaning devices of certain geometries, the modules cells may experience damages driven by localized areas or reverse bias (negative voltage / positive current). While there exist countless ways to shade a module, a few typical field scenarios that pertain to module cleaning can be divided into high, medium and no risk. To minimize the risk of module shading damage please follow the Module Shading Field Guide Special Instruction , M0099721.
Module shading may result in warranty coverage being voided. The following types of High Risk Shading listed below are particularly problematic and related to module cleaning activities.
High Risk (Prohibited) Shading
- Resting or adhering slender objects (tools, brooms, clothing, wires, tape) on sunny side of operating modules, or within inches above operating modules, especially when shadow oriented parallel to cells. An example is shown in Illustration 2.
- Fixed objects within five to seven feet above operating modules that cast a shadow over the long dimension of the cell should be avoided. Close objects like posts, ropes, signs, fences, or equipment can begin to increase risk of partial shading of full cells when nearer than five to seven feet from the sunny-side of operating module.
- Working continuously with outstretched arms or tools over operating modules.
- A support frame or mounting method on the short edge(s) of modules that fully shades the entire length of a cell (either partially or completely).
- Cleaning apparatuses, including cleaning robots and other mechanisms that traverse the module repeatedly while the system is operating (unless evaluated and approved by Cat).
Note: The customer, project owner, O&M provider, or entity responsible for the project site is responsible for determining the extent to which any cleaning method is suitable for use on modules and use in an outdoor environment.
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| Illustration 2 | g06360893 |
Cat does not provide Warranty on modules that are deemed damaged by the cleaning methods used.
Cat warrants its modules according to the Cat PVT 110 and PVT 110 ARC Module Warranty Terms & Conditions provided the modules are installed, operated and serviced as described in the Cat PVT 110 and PVT 110 ARC User Guide and in the System Design and Application document.
For additional question regarding cleaning methods or approvals of mechanical cleaning methods, please contact the Cat Technical Services team at cat.com.