4 ways to share defect locations at solar power plants using drone surveying

In solar power plants, the areas that need inspection tend to be extensive, including panels, mounting structures, graded surfaces, drainage facilities, fences, access roads, and slopes. Even if a defect is found on site, if the way its location is communicated is vague, repair personnel may have to search for the same spot again, and there may be misunderstandings among stakeholders. This is especially true at large-scale plants, where expressions like "the far north side," "near the drainage ditch," or "around which row" alone can easily cause confusion on site.

One useful method is sharing fault locations using aerial images, orthomosaic images, three-dimensional data, and geolocation obtained from drone surveying. Drone surveying of solar power plants can be used not only to record current conditions, but also to create materials that allow stakeholders to confirm on the same map where and what kinds of faults may be occurring.

This article explains four tips for clearly sharing defect locations for practitioners searching for information on "solar power plant drone surveying." It is organized from a practical perspective to make it easy to use for on-site inspections, maintenance management, repair instructions, and report preparation.

Table of Contents

• Why drone surveying is useful for sharing fault locations at solar power plants

• Technique 1 Organize defect locations on the orthophoto image

• Tip 2 Convey information by combining coordinates and on-site landmarks

• Measure 3: Link defect types and priorities to location information

• Tip 4: Compile shared materials so stakeholders do not get confused

• Precautions when using drone surveying for defect management

• Summary

Why drone surveying is useful for sharing fault locations at solar power plants

In the operation and maintenance of solar power plants, it is important to accurately share defects discovered on site. These defects are not limited to dirt or damage on panel surfaces; they cover a wide range of issues such as tilting of mounting structures, ground subsidence, poor drainage, sediment runoff, fence deformation, ruts in maintenance roads, slope failures, overgrowth of weeds, and abnormalities around cables. Some of these relate directly to the power generation equipment itself, while others concern site management and safety management.

On-site work commonly involves the person in charge walking the site, taking photos, and leaving notes. This method is effective for checking details, but it can be time-consuming to organize the photos afterward and determine where on a large site each photo was taken. When a photo folder contains many similar scenes, it can take time just to recall the shooting locations. Also, descriptions that make sense to people who know the site well may be hard for other staff, subcontractors, or clients to understand.

By using drone surveying, you can create images that provide an aerial overview of the entire power plant and orthophotos that are as easy to use as maps. An orthophoto is an image in which distortions caused by terrain and camera angle have been corrected, making it easier to understand positional relationships. By overlaying defect locations on it, it becomes easier to visually share exactly where the problem is on site. The arrangement of panel rows, service roads, drainage channels, retention basins, slopes, fences, and so on can be confirmed on a single image, so stakeholders can more easily discuss matters from the same premise.

Also, a strength of the data produced by drone surveys is that it not only provides point locations but also makes it easy to simultaneously grasp the surrounding conditions. For example, when sharing the location of a puddle, you can confirm not just that “there is a puddle” but also the surrounding slope, where the water drains to, nearby rows of panels, and its relationship to maintenance roads. In the case of slope deformation, it becomes easier to examine the extent of any collapse and the potential impact downstream. In the case of weed overgrowth, you can also check how shadows fall and the relationship with inspection routes.

At solar power plants, multiple stakeholders handle information, including on-site personnel, maintenance managers, design staff, construction companies, repair contractors, and power plant operators. Because each may not be able to visit the site frequently, having materials that can accurately share locations makes it easier to make decisions and plan work. Using drone survey results for defect management can reduce the need for repeated on-site checks, mistakes in identifying locations, and ambiguity in repair instructions.

However, conducting drone surveys does not automatically ensure effective sharing of defects. Simply handing over the captured images often results in materials where it is unclear what to look at. To make them easy to share, you need to be deliberate about how you indicate defect locations, how you use coordinates and reference points, how you sort by priority, and how you organize the documentation.

Technique 1 Organize defect locations on orthophotos

The first task when sharing defect locations is to organize the defective points on an orthomosaic image created by a drone survey. An orthomosaic can be treated like an overhead map of the entire solar power plant, making it a useful resource for conveying spatial relationships to stakeholders who are not familiar with the site.

When you try to share defects using only on-site photos, you may be able to see details of what appears in the photo but find it difficult to determine where on the overall site it is. This is especially true at solar power plants, where similar rows of panels extend across large areas, making it difficult in many cases to pinpoint the location from photos alone. If you overlay the defect location on an orthophoto, you can immediately confirm its positional relationship with panel rows, access paths, drainage facilities, fences, slopes, and other features.

When organizing defect locations, rather than simply marking points, it's more practical in the field to consider how large an area is affected. For example, some issues can be shown as points, such as damage to a single panel, while others—like poor drainage, sediment accumulation, or heavy weed growth—are easier to understand when represented as areas. Ruts in access roads or clogged drainage channels may be more effectively conveyed when shown as lines.

By distinguishing between points, lines, and areas, the nature of defects becomes easier to convey. When shown as a point, it indicates the center of the relevant location or an inspection point. When shown as a line, it represents the range where abnormalities continue or the route that needs to be inspected. When shown as an area, it represents the affected area or the area subject to repair. This helps people working on site understand not only "where to go" but also "what area to check."

Also, assigning defect numbers on the orthophoto makes management easier. For example, assign a management number to each defect and organize the number, description, inspection date, photo number, and response status in a separate sheet or list. Although tables are not used in the main text, it is convenient to list them in practical management documents. By using numbers, stakeholders can refer to “Defect No. 3” instead of “the location of poor drainage,” enabling more specific communication.

When using orthophotos, attention must be paid to the image orientation and scale. If a document does not make clear whether the top is north or the direction of the site entrance, viewers may interpret it differently. Including a north arrow, a legend, major reference features, site boundaries, and access/maintenance roads makes on-site cross-checking easier. If the power plant has block or area names, overlaying those as well is even more practical.

When sharing defect information for solar power plants, it is important to combine detailed on-site photographs with orthoimages. Showing the overall location with an orthoimage and confirming the condition of the defect with on-site photographs improves the clarity of the documentation. Because some details are difficult to see from above, supplement with ground-level or close-up photos as needed. Being aware that drone surveys are strong for overall situational awareness while ground inspections are strong for detailed checks will improve the accuracy of defect sharing.

Using orthophotos to organize information also helps with before-and-after comparisons of repairs. Record defect locations before repairs and check the same locations afterward to make it easier to track which areas have been addressed. Maintenance of a power plant is not a one-time task but an ongoing process, so by accumulating location information you can identify spots prone to recurrence and areas that require attention.

Tip 2: Communicate by Combining Coordinates and On-site Landmarks

To accurately share the location of a defect, it is important to convey it not only with an orthophoto image but also by combining coordinates and on-site landmarks. Drone survey outputs can include location information, but people working in the field do not necessarily act based solely on coordinates. Conversely, relying only on on-site landmarks can make the depiction of the location ambiguous. Therefore, it is effective to use both numerically verifiable information and information that can be seen on site.

The advantage of using coordinates is that they make it easy to indicate positions objectively. Latitude and longitude, plane rectangular coordinates, site-specific coordinates, and so on — management methods vary by project, but if you clarify which coordinate system to use, it becomes easier for stakeholders to reproduce locations. Especially at large solar power plants, relying solely on landmarks can lead to confusing similar-looking spots. With coordinates, repair personnel can more easily move around while confirming positions with mobile devices or surveying equipment.

On the other hand, sharing only coordinates can be difficult for personnel with limited field experience or stakeholders who are not familiar with drawings to understand. Therefore, in addition to coordinates, we include landmarks that can be verified on site. For example, use easily found on-site features as reference points, such as junctions of access roads, fence corners, ends of panel rows, drainage ditches, detention basins, small benches on slopes, areas around electrical equipment, and site entrances.

However, when using landmarks, it's important to choose ones that are unlikely to change over time. Temporary structures, work vehicles, storage areas, and the condition of weeds can change as time passes, so they are not suitable for long-term location sharing. Using relatively stable features—such as access roads, structures, drainage facilities, fences, and plot names—as reference makes it easier to convey the location when reviewing it later.

Descriptions of defect locations become more practical for field use if made specific. "Near the drainage ditch on the south side" is too broad, so express it including direction of travel and reference points, for example: "the drainage ditch along the south maintenance road, near the third cross drain as seen from the entrance." However, because overly long sentences become hard to read, it is important to organize information by combining the number on the ortho image, coordinates, and on-site landmarks.

Care must also be taken regarding coordinate accuracy. Positional accuracy in drone surveying varies depending on imaging conditions, the placement of control points, processing methods, and the positioning techniques used. The required accuracy differs depending on whether the purpose of sharing the defect location is for on-site inspection and repair instructions or for use as precise surveying results. If the material is intended to help repair personnel locate the site, combining it with nearby landmarks may be sufficient. On the other hand, for applications such as comparing against boundaries or design values, separate accuracy verification and clarification of surveying conditions are necessary.

In solar power plants, pay attention to mixing coordinate systems. If the coordinate systems used in design drawings, construction drawings, survey results, and maintenance documents differ, discrepancies can occur even though they are intended to indicate the same location. For shared documents, it is safer to clearly state which coordinate system is being used and which result the coordinate values are based on. When using local coordinates, confirm with stakeholders the concept/definition of reference points and the origin.

Also, for materials used on-site, it's useful to include not only coordinates but also easily navigable routes. In a large power plant, even when you know the location of a fault, it's important to know which access road is best to enter from, how close you can get by vehicle, and which direction to proceed on foot. Using drone survey imagery gives an overview of the layout of access roads and walkways, making it easier to plan the order of on-site inspections and patrol routes.

Combining coordinates with on-site markers not only prevents misidentification of defects but also shortens work time. If stakeholders can confirm the same location without hesitation, the need for re-inspections and confirmation calls is reduced. Especially when inspecting multiple defects at once, insufficient organization of location information leads to increased wasted movement. By utilizing drone survey results as maps and organizing coordinates and markers, it becomes easier to improve the efficiency of on-site responses.

Approach 3: Associate defect types and priorities with location information

When sharing the location of an issue, it is important to link not only the place but also the type of issue and its priority to the location information. Even if the position is known, if it is unclear what should be checked and in what order responses should be carried out, on-site work will be difficult to advance. In solar power plants, urgency and the responsible personnel differ depending on the nature of the issue, so it is necessary to organize location information and content information together.

For example, dirt on panel surfaces, weeds around the mounting racks, sediment buildup in drainage channels, small scouring on slopes, and partial deformation of fences can all qualify as defects to be managed. However, items that require immediate safety measures, those that can be addressed through planned repairs, and those suitable for monitoring have different priorities for response. Listing only location information makes it difficult for stakeholders to determine where to start addressing them.

It's easier to organize types of defects if you establish classification rules in advance. Classify them according to the power plant's actual management situation, such as equipment-related, civil-works-related, drainage-related, perimeter-management-related, vegetation-management-related, and safety-management-related categories. Having classifications makes it easier to allocate issues to the responsible departments and partner companies. For example, defects related to drainage facilities can be assigned to civil engineering, defects related to panels and mounting structures to the equipment department, and defects related to fences and access roads to maintenance management, which makes the response workflow easier to organize.

When assigning priorities, it is important not to judge only by apparent size. Even a small erosion can expand if it is located where rainwater concentrates. Even minor fence damage can lead to unauthorized entry or animal intrusion. Weeds around rows of panels should also be considered in terms of their impact on power generation, safety, ease of inspection, and likelihood of regrowth. While viewing surrounding conditions from drone survey images, it is important to consider the impact on the entire site rather than treating defects in isolation.

Associating priorities with location information makes it easier to determine the order of on-site inspections. By separating locations that require urgent checks, those to be checked on the next patrol, and those to be monitored during routine inspections, you can respond efficiently within limited time. In large-scale solar power plants, it can be difficult to inspect all faults to the same depth on the same day. Organizing priorities makes it less likely to overlook important areas while reducing the burden on the site.

When sharing the condition of a defect, the discovery date and the date of confirmation are also important. Images produced by drone surveys record the condition at that point in time. If heavy rain, strong winds, land development work, vegetation clearing, or repair work have occurred after the capture, the on-site condition may have changed. Therefore, link location information to the capture date, confirmation date, and document creation date to make clear which point in time the condition represents.

It is also important to determine whether defects are recurring in the same locations. Conducting regular drone surveys makes it easier to compare past images with current ones. You can identify trends such as recurring drainage failures at the same spot, spreading scour on parts of slopes, deepening ruts in maintenance roads, and an expanding extent of weed growth. Keeping a history of location information enables not only one-off repairs but also consideration of fundamental improvement measures.

When recording defects, it is also important to standardize expressions. If each person in charge uses words differently—such as "broken," "deformed," "abnormal," or "needs checking"—it becomes difficult to judge the severity of the condition later. If possible, decide in advance how to classify defects, the condition, suspected cause, recommended action, and response deadline. You do not need to define everything in detail, but even having minimum recording rules will stabilize the quality of shared documents.

Drone survey results have the advantage of capturing a wide area at once, making it easier to identify biases in defects. If defects are concentrated in a particular drainage direction, if there is heavy sediment accumulation at the lower parts of certain slopes, or if there are many deformations along the perimeter fence, observing the distribution makes it easier to form hypotheses about the causes. This can be difficult to notice when looking only at individual on-site photos.

By linking the type of defect and its priority to location data, a mere discovery record is transformed into management information that enables actual follow-up actions. If you want to leverage drone surveys of solar power plants for defect sharing, it's important not to stop at "where it is" but to connect through to "what is happening," "how important it is," and "who will check it and when."

Tip 4: Compile shared materials that prevent stakeholders from getting confused

Even if you organize defect locations from drone surveys, if the way to create shared documents is hard to understand you won’t be able to fully use them for on-site responses. To make documents that stakeholders won’t get confused by, you need to standardize the viewing order, how locations are indicated, correspondence with photos, and the method for confirming response status. In managing defects at photovoltaic power plants, the people who read the documents are not necessarily only the on-site personnel. It is important to compile materials assuming that people in different positions—power plant operators, maintenance management companies, construction companies, repair contractors, design personnel, and others—will be looking at the same documents.

In shared documents, it is more practical to use a structure that first shows an overall view and then allows checking the details for each defect location. If only detailed photos are lined up from the start, it becomes difficult to tell where in the whole they are occurring. By labeling the overall orthophoto with defect numbers and then presenting detailed descriptions and photos for each number, viewers are less likely to get lost.

At the beginning of the document, concisely state the subject power plant, date of capture, scope of inspection, survey data used, and any notes. For example, whether this document covers the entire site or only certain areas will affect how readers interpret it. If there are areas excluded from the scope, explicitly state that to avoid misunderstandings. Also, if there are locations that cannot be seen in the drone survey images or areas that require ground verification, it is safer to note these in the document.

When creating a detailed page for each defect, organizing them in the same format makes comparison easier. Record the number, location, classification, condition, inspection date, photos, recommended actions, notes, etc., in the same order every time. When the document format is standardized, it reduces the burden on the reader when reviewing multiple defects. Conversely, if the writing differs from page to page, it takes longer to find important information.

When attaching on-site photos, match the numbers on the orthophoto with the photo numbers. Rather than just lining up photos, make clear which numbered defect each photo depicts. If the shooting direction is important, indicate which way the photo was taken to make it easier to understand. For example, slope deformations and drainage paths can look different depending on the shooting direction, so whether a photo was taken from the upstream side or the downstream side can be important.

In shared documents, consider how colors and symbols are used. It can be helpful to visually distinguish urgent items, items under observation, and items that have been handled, but relying on color alone can lead to oversights or misunderstandings. It is safer to accompany color with numbers, category names, or textual status information. Make sure they can be distinguished when printed or shown in black and white so they are easier to use in the field.

When sharing with stakeholders, version control of documents is also important. Defect management documents are updated through on-site inspections, repairs, and re-inspections. If old and new documents coexist, there is a risk of reissuing instructions for items that have already been addressed or overlooking items that have not been handled. Including the creation date or version number in the document name and keeping a revision history makes it easier to determine which document is the latest.

Also, shared materials need to be created with on-site use in mind. Even if they are easy to read on a large office screen, when checked on site while looking at a mobile device or printed materials, text can be too small and the spatial relationships in images can be hard to discern. To make them easy for personnel to use on site, consider measures such as separating overall plans and detail drawings, displaying important numbers prominently, and including reference points like entrances and access roads.

When sharing defect information, it's important not to stop at simply handing over the documents. At the initial sharing, aligning stakeholders on how to interpret the materials, the meaning of the numbering, how to determine priorities, and how to proceed with on-site checks will make subsequent communications smoother. In particular, when multiple partner companies are involved, using the same numbering system and location information can reduce miscommunication.

The results of drone surveying provide a convenient resource that offers an overview of the entire power plant, but their value increases when they are organized in a way that enables stakeholders to take action. By creating materials that link overview maps, detailed photos, location data, classifications, priority levels, and response status, it becomes easier to manage the workflow from defect detection through repair and reinspection.

Considerations When Using Drone Surveying for Defect Management

When using drone surveying to share fault locations at solar power plants, there are several points to note. First, you cannot determine all faults from drone survey images alone. Some faults are visible from above, while others can only be confirmed by getting closer. The backs of panels, joints of mounting structures, fine details of cables, the interiors of drainage ditches, and ground surfaces hidden by vegetation can be difficult to assess from drone images alone.

Therefore, it is realistic to use drone surveying for gaining a broad overview and sharing locations, and to supplement it with on-site verification where necessary. By using drone images to identify places that may have abnormalities and then conducting detailed checks on site, the efficiency of inspections carried out on foot can be increased. Conversely, drawing conclusions about causes or safety based solely on drone images can lead to oversights or incorrect judgments.

Attention must also be paid to shooting conditions. In solar power plants, appearances vary due to panel reflections, shadows, backlighting, grass height, terrain undulation, and weather. If the time of day, altitude, overlap rate, or camera orientation are not appropriate, the quality and interpretability of orthophotos can be reduced. When the purpose is to share defect locations, it is important not merely to take pretty images but to choose conditions that make on-site conditions easy to interpret.

Positional accuracy should also be verified according to the intended purpose. Materials used by maintenance personnel to locate positions on site and materials used for strict cross-checking against design drawings and boundary information require different levels of accuracy. The extent to which control points are established and coordinates are managed should be determined based on the intended use. Results with insufficient positional accuracy should not be treated as if they were precise survey results.

In addition, safety management for flights and coordination with stakeholders are essential. Solar power plants include electrical equipment, service roads, workers, surrounding private land, and restricted-entry zones. When drawing up a flight plan, organize in advance the local safety conditions, notification to stakeholders, takeoff and landing sites, emergency response, and weather assessment. Operations should be conducted only after ensuring safety in accordance with laws and on-site rules regarding unmanned aircraft.

Careful data management is also necessary. Documents that indicate defect locations may contain information that should not be shared carelessly with parties outside those involved, such as the power plant layout, equipment status, and management issues. It is important to decide the scope of sharing, storage locations, access permissions, and rules for taking data off-site. In particular, when sharing with external partner companies, consider providing materials only to the extent necessary.

Furthermore, it is important to decide on update operations after creating the documentation. Defect management does not end when an issue is discovered. Statuses change — for example, in progress, resolved, awaiting recheck, or under observation. Documentation that is not updated quickly becomes outdated and difficult to use as a basis for on-site decision-making. Deciding who will update documents, when they should be updated, and how past versions will be stored makes them easier to use continuously.

Drone surveying of solar power plants is a useful means of sharing fault locations, but it is not a cure-all. By combining considerations of image appearance, positional accuracy, on-site verification, data management, and safety management in operations, it becomes shared documentation that can withstand practical use.

Summary

To share defect locations at a solar power plant using drone surveying, simply using images taken from above is not sufficient. It is necessary to devise methods of organizing the information so that stakeholders correctly identify the same locations and can proceed with on-site verification and repair.

First, organizing defect locations on an orthoimage makes it easier to visually convey where problems are located within the entire power plant. By using points, lines, and areas and assigning defect numbers, it also becomes easier to correlate with on-site photographs and response records. Next, combining coordinates with on-site landmarks allows you to balance the objectivity of the location with ease of finding it in the field. In practice, using both—rather than relying on coordinates alone or landmarks alone—is effective.

Furthermore, by linking the types of defects and their priorities to location information, you can transform mere location sharing into management information for driving follow-up actions. If you separate locations that require urgent inspection, those to be addressed through planned work, and those to be monitored over time, you can conduct checks efficiently even in large power plants. Finally, by compiling shared materials that prevent stakeholders from becoming confused, you can help streamline the flow of detection, confirmation, repair, and reinspection.

Drone surveying is an effective method for obtaining an aerial overview of the extensive grounds of a solar power plant and for sharing the locations and distribution of faults. However, it is important not to make all judgments based on images alone and to combine them with ground inspections, on-site safety management, and data management. By continuously accumulating records, locations prone to recurrence and areas that require focused management become easier to identify.

If you want to manage faults at a solar power plant more clearly and efficiently, it is important to combine drone surveys that provide an overview of on-site conditions with an easy-to-use method for sharing location information. By organizing the condition across a large plant and establishing a system to accurately share defect locations among stakeholders, you can reduce the need for repeat site visits and rework during inspections and repairs.