Utility companies are discovering that drones can be a valuable asset for power line inspections. Approximately 20% of unexpected power outages are due to trees and other vegetation growing too close to power lines. This poses a threat not only to the electrical equipment that can be damaged by short-circuits or other issues, but also to people and animals nearby and to the forest itself.
When trees are too close to power lines, they can allow electricity to reach the ground, increasing the risk of electrocution. Additionally, they can be a fire hazard, particularly during drought or dry weather when strong winds can blow debris onto the power lines.
Monitoring power lines is crucial to ensure their safety and prevent potential hazards. Both healthy and unhealthy vegetation can pose a threat to power lines, and identifying these hazards is essential for minimizing risks.
Traditional methods of inspecting power lines, such as by helicopter or on foot, can be costly and time-consuming, especially in remote or difficult-to-access areas.
Advantages of Using Drones for Power Line Inspections
Using drones in power line inspection speeds up the proces roughly 10 times faster than the traditional ground-based inspections. Drones can easily inspect power lines in challenging environments such as marshes, wetlands, bogs, and thick forests.
- Minimize the dangers and health risks
- Collect in-depth and detailed inspection data, providing a more accurate and comprehensive view of the power line infrastructure
- Drones can be quickly deployed or launched, making them a time-efficient option for inspections
- Flexibility, as they can be used for a wide range of power line grid inspections
- Data collected by drones is easily shareable, allowing for quick and efficient collaboration
- Access difficult to reach and hazardous areas, providing a safer alternative to traditional inspection methods
- Lower insurance costs
The use of UAV platforms for power line and substation inspections can increase productivity and reduce cost compared to traditional inspection methods.
By using drones with high-resolution cameras and sensors it is possible to create detailed 3D models of power lines and surrounding terrain. Utility companies can improve the safety and reliability of their power grid while also saving time and money.
Drone applications for Power line Inspection
By providing a bird’s eye view of the power lines and their surroundings, drones make it easier to identify any potential issues that may arise. Having the ability to carry various sensors and high-resolution cameras drones are assisting in:
Inspection of Powerline Corridors
Drones equipped with high-resolution cameras can capture images of power lines and towers, providing a detailed view of the infrastructure's condition. The captured data can be used to identify any defects, such as broken wires, rusted components, or chipped insulators. Drones can also be used to inspect hard-to-reach areas, such as transmission towers, which are often challenging to access using traditional inspection methods.
Power outages can be caused by a variety of factors, such as equipment failure, weather events, or wildlife interference. Drones can be used to inspect power lines and identify faults, enabling power utilities to take corrective action quickly. Drones equipped with thermal cameras can detect hotspots caused by damaged components, allowing power utilities to prioritize repairs and prevent power outages.
Management of vegetation
One of the most critical aspects of power line inspection is vegetation management. Overgrown vegetation near power lines can cause power outages and even wildfires, making it essential to monitor and manage vegetation growth regularly. Drones equipped with LiDAR (Light Detection and Ranging) sensors can provide accurate and detailed 3D maps of the surrounding vegetation, allowing power utilities to identify and manage overgrown vegetation before it becomes a problem.
Wildfires are a significant risk to power utilities, and drones can be used to inspect power lines and identify potential fire hazards. Drones equipped with thermal cameras can detect hotspots in the surrounding vegetation, allowing power utilities to identify potential fire hazards and take corrective action. Drones can also be used to inspect power lines after a wildfire to identify any damage and prioritize repairs.
Drones can be used to assess the risk of power line failures in different areas, allowing for targeted maintenance and reducing the overall risk of outages.
Different Types of Drone Data Analysis Used in Power Line Inspections
Power grid operators rely on drone data analysis to detect defects that may be difficult to identify with the naked eye. Unlike traditional on-foot inspection teams, drones can provide closer and more detailed views of power poles and use different sensors for data collection.
The data collected during inspections is uploaded to drone inspection software , where drone data analysis can be conducted. Software allows users to conduct inspections using different inputs such as RGB drone data analysis, Multispectar, LiDAR and infrared drone data analysis.
The impressive results produced by these tools are a result of the high resolution of sensors and an advanced algorithms that allows for the accurate identification of power lines.
Sensors can be radiometrically calibrated for time-based analysis of vegetation changes, providing insight into changes in vegetation over time (such as seasonal or quarterly changes).
RGB data analysis
RGB cameras are designed to measure the red, green, and blue wavebands, which are the same wavebands that our eyes detect. This makes the images produced by RGB cameras intuitive for humans to interpret.
RGB data analysis is a critical component of power line inspections, utilizing photos taken by drones during the data collection phase. Both distribution system operators (DSOs) and transmission system operators (TSOs) use RGB photos to identify defects that would be difficult to detect from the ground.
Drones provide a top-down view of power poles and lines, allowing inspection teams to obtain a comprehensive overview of the asset's condition. In addition, drones enable inspection teams to get close to the top of the poles or towers and take high-resolution images.
Multispectral data analysis
Multispectral sensors are capable of detecting up to 15 different wavebands, including those beyond the visible spectrum and into the near-infrared spectrum. This allows for differentiation between objects that may appear similar in an RGB image. Additionally, multi-spectral sensing can provide valuable information about the properties of an object, making it a powerful tool for a variety of applications.
The high-resolution multispectral data from the sensors can be used to detect encroaching vegetation and other hazards, and various indices and composites can be used to identify areas that require further investigation.
Plants reflect different amounts of light depending on their species, health, and other factors, and multispectral sensors can provide additional data that can be used to identify specific hazards, such as:
- fungal or disease activity
- moisture loss
- insect damage
- species identification
Using drones with multispectral sensors is a cost-effective and efficient method for small or large-scale projects.
LiDAR drone data analysis
LiDAR is a remote measuring method that uses pulsed laser beams to measure distances between the LiDAR apparatus and the ground. During the mapping process, every reflected laser beam creates a point with a calculated height, allowing for the creation of point maps and 3D models of the mapped area.
LiDAR data is extremely accurate and allows for precise measurements to be used for mapping and analyzing the inspected area. Grid operators can use LiDAR data to detect overgrown vegetation and sagging power lines, allowing them to take preemptive actions and prevent disruptions to the power supply.
Infrared data analysis
Infrared images are commonly used in power line inspection data analysis to detect overheating elements and the corona effect. Thermal cameras mounted on drones are used to collect the infrared data. Overheating elements are a clear indication of a possible future breakdown and must be fixed urgently to avoid blackouts and grid downtime. Analyzing the infrared data can easily detect overheating elements as they appear much hotter than surrounding parts and glow brightly in the thermal images.
Common Drone Deliverables for POWER-LINE inspection
Power line inspection drones can generate various types of maps that can be used to identify issues with power lines and other linear infrastructure. The three most common types of maps that can be generated by power line inspection drones are:
A 3D model is a digital representation of a physical object. In the case of power line inspection drones, a 3D model can be generated by taking oblique imagery of power lines and then using third-party tools to composite the images into a 3D model. This type of map can be useful for identifying issues with power lines that may not be visible from a two-dimensional perspective.
3D point cloud
A 3D point cloud is a collection of points in three-dimensional space. In the case of power line inspection drones, a LiDAR drone can be used to acquire the spatial coordinates of each sampled point on the surface of an object, which is then used to generate a collection of points called a “Point Cloud”. This type of map can be useful for identifying issues with power lines that may not be visible from a two-dimensional perspective.
A thermal map is a type of map that shows the temperature distribution of an object or area. In the case of power line inspection drones, thermal cameras mounted on drones can be used to generate thermal maps of power lines. This type of map can be useful for identifying issues with power lines that may not be visible to the naked eye.
Types of drone PLATFORMS used for power line inspections
When it comes to professional drone inspections, there is no single best drone model that fits all scenarios. Instead, there are several different drone models that are suitable for specific circumstances and environments in which inspections are to be conducted.
DJI Matrice series
The DJI Matrice series drones are widely used in power line inspections and are considered the workhorses of the industry. These drones are equipped to capture RGB, thermal, and LiDAR data in low, middle, and high voltage lines, making them one of the best-performing drones for power line inspection. With a maximum takeoff weight of 9kg, the Matrice series drones can be equipped with a wide range of sensors.
The Matrice 300 is DJI's latest addition to their line of professional inspection drones. This drone is compatible with a range of payloads, including high-quality cameras with exceptional zoom functionality through DJI's Zenmuse camera series. As such, the DJI Matrice 300 is currently considered the industry standard for external inspection needs, providing a reliable and versatile solution for various applications.
Autel Robotics Evo II Series drones are a lesser-known but excellent alternative for power line inspections. These drones support video resolutions up to 6K and have a hyper-light feature designed for shooting in low-light conditions, making them a powerful tool for inspections.
The EVO II series is a direct competitor to the Mavic drones and offers a flexible drone for power line inspections with an even greater focus on picture quality. Due to their small size, it is recommended to keep a few sets of spare batteries on hand when conducting drone power line inspections with the EVO II series, similar to the DJI Mavic drones.
Let's try to explain the general overview and process for power line inspection using drones. The work is combined with data collection and data analysis using specialized software like Pix4D.
The raw data collected is processed using surveying software and the Automatic Power Lines Detection tool, which generates a detailed 3D model of the power line corridor. This model includes a 3D polyline for each individual wire, providing a comprehensive view of the power line infrastructure. This allows for a more efficient and accurate inspection process, as the 3D model provides all the necessary information in a single, easy-to-use format.
Using 3D mesh and vegetation index data, problem areas can be easily identified and visualized. The 3D mesh provides a detailed view of the terrain, while the vegetation index shows the health and density of the surrounding vegetation. This combination of data allows for a comprehensive assessment of the power line corridor and any potential issues that may be present. This can help identify areas that require further inspection or maintenance, improving the efficiency and accuracy of the inspection process.
Viewing the 3D mesh provides a quick and easy way to identify vegetation height and the location of poles and other structures within the corridor exclusion zone. In addition, viewing the imagery in different vegetation indices, such as the CIR index, can provide additional information about the health and density of the surrounding vegetation. This allows for a more thorough assessment of the power line corridor and any potential issues that may be present, improving the efficiency and accuracy of the inspection process.
Reviewing imagery in aligned indices and composites beyond just RGB can help identify areas that may require further inspection or maintenance. By looking at the data in different ways, such as through vegetation indices or composited images, it is possible to gain a more comprehensive understanding of the power line corridor and any potential issues that may be present. This can help to identify specific areas that may require further attention, improving the efficiency and accuracy of the inspection process.
Using vegetation indices such as NDVI with a soil filter applied, it is possible to quickly and easily review imagery for vegetation encroachment. This allows for a more efficient and accurate assessment of the power line corridor, as the vegetation indices provide a more detailed view of the surrounding vegetation and the soil filter helps to eliminate false positives.
By using this approach, problem areas can be identified and addressed more quickly, improving the overall efficiency of the inspection process.
While traditional on-foot inspection teams depend on what they see from the ground, drones enable inspection teams to both get a closer look at the power poles and use different sensors for data collection. Using drones for powerline inspection brings significant improvement to Transmission Network Inspection processes.
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