Overhead power lines are critical components of electrical infrastructure, connecting power generation, transmission, and distribution networks across different locations. Because these lines operate in open environments and may extend across large areas, accurate information about their position, height, clearance, condition, and surrounding environment is important for planning, inspection, maintenance, and infrastructure development.
An OHL survey, or Overhead Line Survey, helps collect and document important information about overhead power lines using surveying and inspection technologies.
In the UAE, where infrastructure development and utility networks continue to expand across urban, industrial, and remote areas, reliable survey data can support safer planning and better decision-making.
What Is an OHL Survey?
An OHL survey is a specialised survey carried out to identify and map the location and characteristics of overhead power lines.
The survey involves observing overhead lines, determining their locations, and measuring relevant distances and levels. The collected information can then be analysed and presented through detailed reports and mapping.
Depending on the project requirements, an OHL survey may provide information such as:
- Power line location
- Line levels
- Sag measurements
- Height and clearance
- Temperature-related information
- Voltage details
- Spatial positioning
- Other project-specific survey information
The exact scope depends on the requirements of the power infrastructure project.
Why Is an Overhead Power Line Survey Important?
Overhead power lines can pass through areas containing roads, buildings, industrial facilities, construction sites and other infrastructure.
Accurate information about their location and clearance can therefore be important when planning work around existing electrical infrastructure.
An OHL survey can help project teams understand:
- Where overhead lines are located
- Their relationship to surrounding infrastructure
- Available vertical clearances
- Line levels and geometry
- Potential constraints affecting development
- Existing conditions that need to be considered during planning
Having accurate survey information before work begins can help engineers and project teams make decisions based on measured site conditions rather than assumptions.
What Information Can an OHL Survey Provide?
The information collected during an OHL survey depends on the project’s scope and required deliverables.
Accurate Survey Engineering’s OHL survey service includes reports covering sag, temperature, level, height clearance and voltage details.
Sag Information
The sag of an overhead conductor refers to the vertical curve formed by the line between its supporting points.
Understanding sag can be important when evaluating the position and clearance of overhead lines.
Height and Clearance
Clearance information can help establish the relationship between overhead lines and the ground, roads, structures, or other nearby elements.
This can be particularly relevant when planning construction or infrastructure work near existing power lines.
Level Information
Surveyed level information provides additional spatial information about the overhead line and surrounding site conditions.
Temperature Information
Temperature data can be included as part of the OHL reporting requirements where relevant to the project.
Voltage Details
Voltage information can also form part of the OHL survey report, depending on the project scope.
How Is an OHL Survey Conducted?
An OHL survey can involve several technologies and surveying methods depending on the site and project requirements.
Accurate Survey Engineering states that its OHL surveys are carried out using drone inspection, GPS, and thermal imaging technology.
A typical project may include the following stages.
1. Understanding the Project Requirements
The survey team first establishes the survey area, overhead line network, required measurements, expected deliverables and site conditions.
2. Site Assessment
The survey area is assessed to understand access conditions, surrounding infrastructure and potential safety considerations.
This is particularly important when the work takes place near high-voltage electrical infrastructure.
3. Data Collection
Survey and inspection technologies can then be used to collect the required information.
Depending on the project, this can include aerial data, positioning information and thermal imagery.
4. Data Processing
The collected information is processed and analysed to identify the required measurements and characteristics of the overhead lines.
5. Report Preparation
The final information is organised into a survey report containing the relevant measurements and project-specific details.
What Technologies Are Used in OHL Surveys?
Modern OHL surveys can combine several technologies to improve the collection of information.
Drone Inspection
Drones can provide aerial imagery and data from areas that may be difficult or inefficient to inspect from the ground.
They can be particularly useful when overhead infrastructure extends across large or difficult-to-access areas.
Accurate Survey Engineering also provides dedicated drone inspection services for infrastructure and assets.
GPS Surveying
GPS technology can be used to establish accurate positioning information for the survey.
This helps connect the observed overhead infrastructure with its geographic location.
Thermal Imaging
Thermal imaging can provide temperature-related information and help capture thermal data from infrastructure where required by the project.
Combining different technologies can provide a more comprehensive view of the surveyed overhead line system.
What Are the Challenges of Surveying Overhead Power Lines?
Overhead power line surveys can present several practical challenges.
Working Near High-Voltage Infrastructure
Safety remains one of the primary considerations.
Survey teams may need to work in proximity to high-voltage power lines, making appropriate safety procedures and planning essential.
Accurate Survey Engineering specifically notes that its OHL survey work involves high safety measures due to the proximity to high-voltage power lines.
Difficult or Restricted Access
Some overhead lines may cross remote, elevated, industrial, or otherwise difficult-to-access areas.
Traditional ground-based surveying methods may not always provide convenient access to every location.
Large Survey Areas
Power line networks can extend over considerable distances, creating a need for efficient data collection and processing.
Complex Surrounding Infrastructure
Urban and industrial environments may contain buildings, roads, towers, utilities and other structures close to overhead lines.
Accurate spatial information is therefore important when assessing the relationship between the power lines and surrounding assets.
When Do You Need an OHL Survey?
The exact requirement depends on the project, but an OHL survey can be useful when accurate information about existing overhead power lines is required.
Potential applications include:
- Infrastructure planning
- Construction planning
- Utility mapping
- Power infrastructure assessment
- Clearance assessment
- Engineering surveys
- Site development
- Infrastructure inspection
- Existing-condition documentation
For projects involving construction or development near overhead electrical infrastructure, survey information can provide engineers and project teams with important existing-site data.
OHL Survey for Construction and Infrastructure Projects
Construction projects may encounter overhead power lines within or around the project area.
Before construction activities begin, project teams may need to understand the location and clearance of these lines so that the existing electrical infrastructure can be considered during planning.
An OHL survey can provide measured information that can support:
- Site planning
- Engineering design
- Construction coordination
- Utility identification
- Clearance assessment
- Infrastructure documentation
The survey data should be considered alongside the project’s engineering requirements and applicable safety procedures.
What Should You Consider When Choosing an OHL Survey Company in the UAE?
Selecting a survey provider involves more than checking whether they offer OHL surveys.
Consider the following factors.
Experience With Specialised Surveys
OHL surveys involve different requirements from conventional land surveys. Look for a provider with experience in specialised infrastructure surveying.
Survey Technology
Ask what technologies are available for the project.
Depending on the scope, this may include:
- GPS
- Drone inspection
- Thermal imaging
- Other appropriate surveying equipment
Safety Procedures
Safety should be a fundamental consideration when survey teams work near high-voltage infrastructure.
Ask how the survey team approaches site safety, access and data collection.
Reporting Requirements
Before starting the project, clarify what information needs to be included in the final report.
This could include:
- Sag
- Levels
- Height
- Clearance
- Temperature
- Voltage details
Project-Specific Approach
Every OHL survey site is different. The survey methodology should therefore be established according to the site conditions and project requirements.
How Drone Technology Can Support OHL Surveys
Drone technology has changed the way aerial inspection and data collection can be approached.
Instead of relying entirely on ground-based observations, drones can capture aerial imagery and information from different viewpoints.
Potential advantages include:
- Access to difficult areas
- Aerial perspective
- Efficient visual data collection
- Reduced need for physical access to certain locations
- Support for large-area infrastructure inspection
However, drone operations around electrical infrastructure still require appropriate planning, safety controls, permissions and qualified personnel.
Drone technology should therefore be considered as part of a broader survey methodology rather than as a replacement for professional surveying expertise.
OHL Survey vs. General Land Survey
An OHL survey and a general land survey serve different purposes.
A land survey may focus on property boundaries, topographic information, levels, coordinates, structures and other site features.
An OHL survey is specifically concerned with overhead power line infrastructure and the information required to understand its location, geometry, clearance and related characteristics.
For projects involving overhead electrical infrastructure, a specialised OHL survey may therefore be required in addition to other types of engineering surveys.
What Does an OHL Survey Report Include?
The final deliverables may vary based on the project requirements.
An OHL survey report may include relevant information such as:
- Surveyed line locations
- Sag information
- Levels
- Height measurements
- Clearance information
- Temperature data
- Voltage details
- Supporting survey information
- Maps or visual documentation
Before starting the survey, it is useful to confirm the required deliverables with the survey provider so that the data collected aligns with the project’s engineering requirements.
Why Accurate Survey Engineering for OHL Surveys?
At Accurate Survey Engineering, we provide specialised OHL survey services focused on accurately identifying and mapping overhead power line infrastructure.
Our OHL survey service uses drone inspection, GPS, and thermal imaging technology to collect relevant information for project-specific reporting. Our reports can include details such as sag, temperature, levels, height clearance and voltage, depending on the requirements of the survey.
Because OHL surveys can involve working close to high-voltage power lines, safety is an important part of the survey process. Our team follows safety measures while carrying out these specialised surveys.
If your project requires reliable information about existing overhead power lines, our team can assess the survey requirements and provide an appropriate approach based on the site and project scope.
Need OHL Survey Services in the UAE?
Accurate information is essential when working around existing overhead power line infrastructure. An OHL survey can provide project teams with important information about line locations, levels, sag, height, clearance and other relevant characteristics.
Accurate Survey Engineering provides specialised OHL survey services using drone inspection, GPS and thermal imaging technology, with reporting tailored to project requirements.
If you are planning an infrastructure, construction or engineering project that requires an OHL survey in the UAE, contact Accurate Survey Engineering to discuss your survey requirements.