- 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
This Special Instruction provides supplemental information about response of Cat® PVT 110 and PVT 110 ARC Photovoltaic Module due to partial module surface area shading.
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.
Safety Section
Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs.
A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly.
Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.
Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. Ensure that any tool, procedure, work method, or operating technique you use that is not recommended by Caterpillar is safe.
Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or repair procedures used.
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. |
Failure to follow all safety guidelines prescribed in this document and by governing authorities and regulatory agencies may result in severe injury or death of personnel or machine damage. |
When removing a major component or attachment, ensure that it is properly blocked or secured before removing mounting hardware. An assembly that is disconnected without proper blocking may shift or fall, resulting in serious injury or death of personnel or machine damage. |
Personal injury or death can result from improper maintenance procedures. To avoid injury or death, follow the procedures exactly as stated below. |
Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any chemical that is used. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of chemicals. |
Climbing equipment may be required to access this service point. Refer to the Operation and Maintenance Manual, "Mounting and Dismounting" topic for safety information. |
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. |
Do not operate the machine if any guards or covers are missing or inadequately secured. Personnel could be seriously injured or machine damage may occur. |
Observe the safe working load limits of all lifting and blocking devices and keep a safe distance from suspended/blocked loads. Personnel may be seriously injured or killed by falling loads. |
Module Characterization Response of Photovoltaic Modules to Partial Shading
Purpose
The information contained in this document provides supplemental information about the response of CAT PVT 110 and PVT 110 ARC due to partial module surface area shading and its dependence on the orientation of the shading. The data is intended to support the proper design of systems using these CAT PVT 110 and PVT 110 ARC modules as well as the development of more accurate models for energy prediction. The data is representative of all power bins of CAT PVT 110 and PVT 110 ARC Modules, although some variation among the modules is normal and to be expected.
Shading Parallel to Cells
Illustration 1 | g06361104 |
Shaded along |
Illustration 2 | g06361108 |
I(V) Characteristic, Partially shaded Cat PVT 110 and PVT 110 ARC module with entire cells shaded. |
Illustration 2 shows how the IV curve of a single Cat PVT 110 and PVT 110 ARC module changes as entire cells are shaded. In this case, shading occurred along the
Illustration 3 | g06361110 |
P(V) Characteristic, Partially shaded Cat PVT 110 and PVT 110 ARC module with entire cells shaded. |
This effect is also evident in Illustration 3, which shows P(V) curves corresponding to the I(V) curves shown in Illustration 2. Response of the relative module power output to shading percentage is shown in Illustration 7, which indicates that the module ceases producing power when more than half of the cells are entirely shaded.
Shading Perpendicular to Cells
Illustration 4 | g06361105 |
Shaded along |
Illustration 5 | g06361115 |
Partially shaded Cat PVT 110 and PVT 110 ARC module with equal portions of all cells shaded. |
Illustration 6 | g06361116 |
Partially shaded Cat PVT 110 and PVT 110 ARC module with equal portions of all cells shaded. |
Illustration 7 | g06361117 |
Relative power output vs shaded portion of module. |
The response of the module to shading along the
The maximum power current IMP varies directly with un-shaded (active) cell area. Since this dependence is linear, and since the VMP response is only weakly dependent upon shaded area, the resulting dependence of module power is nearly linear with shaded area percentage. This behavior is clearly shown in Illustration 7. A linear fit to the relative power versus shading percentage in the
Conclusion
Cat PVT 110 and PVT 110 ARC module respond differently to partial shading depending on shading orientation. If the shading occurs along the
If the module is shaded along the
Based on these behaviors, module power loss due to shading will be minimized when shading can be restricted to occur along the