INSPECTIONS

 

VIADUCTS

In the United States there are more than 600 thousand bridges, many of which – 10 percent – are classified as obsolete and to be kept under constant control. In Italy the numbers are lower, but a technology like this could still intensify monitoring, lower costs and allow more timely interventions. Also to avoid the repetition of tragedies like that of Genoa.

The recent collapse of the Morandi bridge, in its gravity, has highlighted a problem that has been known for some time concerning the monitoring and maintenance of Italian civil works.
The issue does not only concern bridges or the motorway network but all civil works relevant to safety and the economy. Surely the bodies in charge will improve the monitoring of the status of the civil works, for example by setting up databases relating to the bridges that highlight any structural deficit as is already the case in the USA: https://www.artbabridgereport.org

The monitoring activities take place in different ways; from visual to instrumental checks. Based on the findings, the technicians can identify any critical issues that require further checks in order to determine the necessary interventions.

A valid support to the various monitoring activities are the drones.
Existing practices must exploit the opportunity offered by drone technology and put operators at risk only when all other options have been exhausted.
An advantage of the use of drones is the visual controls, which can be performed more frequently and in a timely manner, at lower costs, avoiding that technicians have to operate in intrinsically dangerous environments by using complex structures to reach the various structural elements.

Use of drones in critical environments
Drones can also be used in environments that are critical due to electromagnetic interference or limited accessibility to places.
The latest generation of drones are equipped with:

  • Redundant electronic systems for flight and safe positioning
  • Shields to avoid interference due to electro-magnetic fields
  • Precise positioning systems with double on-board antenna, ground beacon and double satellite system
  • Presence of transponders on board to avoid interfering with other aircraft
 

STRUCTURES

In a 2016 report called Bridging Global Infrastructure Gaps, the McKinsey Global Institute estimated a global gap of $ 350 billion between annual infrastructure investments and what is needed to support expected growth rates. Unless companies can fill this gap, communities will be hit by dangerous and congested transport systems, inefficient telecommunications networks and an expensive and unreliable power grid. The current model for addressing this problem is to put pressure on governments to make the difference on their own or create laws that further encourage private investment. Although this model should be pursued, companies in the sector should turn to new technologies to reduce the gap through efficiency improvements.

Considering this investment gap and the potential to improve our urban environments through smarter maintenance and infrastructure construction, DJI has applied its drone technology to meet the needs of the industry. This new line of corporate drones has been built from the ground up to assist in critical infrastructure and energy projects. For those unfamiliar with the application of drone technology, it focuses on capturing geo-referenced data from a wide range of sensors that not only drive efficiency gains in current methods, but also allow the development of new high methodologies data intensity. Furthermore, many inspections require engineers to resize tall structures. These methods require not only time due to the necessary safety preparations, but are also inherently dangerous. Existing practices must exploit the opportunities offered by drone technology and put workers at risk only when all other options have been exhausted.

With a completely redesigned design, this model is the most robust and adaptable platform on the market. With new flight planning and operations management software, users can now accurately view projects faster than ever. The fully integrated platform allows teams to focus on project management rather than on the tool.

Maintenance of obsolete infrastructure networks

In the United States, as in many other developed economies, communities have made major infrastructure investments decades ago and now these networks are aging rapidly. This can cause economic inefficiencies and even risk one’s life when bridges fail. The American Road & Transportation Builders Association, in Bridge Report 2017, found that “there are 185 million daily crossings on almost 56,000 structurally deficient US bridges”. With these numbers only to increase, teams need a way to prioritize maintenance and increase efficiency with the teams they have.

With this model, pilots can configure a zoom camera like Zenmuse Z30 above or below the drone to fully view a bridge, allowing civil engineers to quickly understand where the bridge is structurally weak and plan maintenance further. Without a model like this pilot to constantly find problems, communities pay considerably more for less frequent and detailed inspection. Furthermore, since the current methods struggle to document the site from all angles, maintenance workers called after the inspection may often not have the complete picture, leading to repeated visits to completely resolve all maintenance requests.

In addition to assisting with bridge inspections, we can also keep energy facilities at peak efficiency through more detailed inspections. Inspectors can configure the drone to acquire visual and thermal information in tandem, allowing inspection teams to cover more ground in a single day. The payload options are also sufficiently powerful, with the ability to reach a resolution of less than a millimeter at distances up to 50 meters and a half degree thermal sensitivity.
This technology is particularly important for renewable energy resources and telecommunications networks, where companies often place wind turbines, solar panels and cell towers in remote areas. With the online operating portal DJI FlightHub, pilots can immediately transmit inspections to a team of off-site engineers, allowing teams to collaborate remotely when facing areas of interest. This allows operators to manage existing infrastructure resources more efficiently and to focus on investing in new projects.

Reduction of maintenance and construction costs for new projects

The aforementioned report from the McKinsey Global Institute found that emerging economies account for 60% of the annual investment needed in infrastructure, which represents a unique opportunity to integrate technology at the beginning. Because the BIM and VDC processes are becoming common practice in long-term construction projects, drones are a key component in realizing the full potential of digital workflows as they provide data on demand to compare progress with plans. Data acquired from drones amplify efficiency gains throughout the project life cycle, from design to maintenance decades later. For example, with an X4S camera it is possible to provide daily data to quickly generate a georeferenced orthomosaic of the project that can be held to track progress and verify the work done by contractors. This works to quickly resolve any conflicts between subcontractors and allows managers to easily keep track of project timelines by minimizing the time needed to respond to RFI.

As economies continue to develop, we are seeing strong increases in per capita energy consumption. This means that countries must keep pace with the growing demand by investing in new energy facilities and power line networks to ensure stable and affordable energy. We are able to increase the efficiency and the rate of return on these sites, significantly reducing maintenance costs, effectively increasing the investment offer for these projects. For example, previous versions of drones for aerial technology were able to reduce data collection times for visual and thermal solar panel inspections at 8 sites from 4 days to 1 and a half. With this new technology, flight times would have been halved because the pilots could have mounted both a visual and a thermal camera. In addition, interested site managers may have immediately reviewed and processed the data from this site and many others, if distributed on a large scale, with FlightHub, simplifying the current inspection workflow.

An additional limit to growth for emerging countries is the ability to properly maintain and integrate the electricity grids that were erected decades earlier. Many of these networks were poorly documented, leaving gaps in maintenance records. With this improved and robust design, energy companies can send inspectors to assess the structural integrity of insulators and measure cable temperatures to identify damaged lines with little concern for weather conditions that previously could delay a project of days or even weeks. With a detailed view of these extended networks, utilities can properly plan how to update these networks and efficiently maintain those that cannot update immediately.

 

ELECTRIC LINES

Electric power distribution lines for high voltage power lines, consisting of cables and pylons, are not without problems relating to maintenance and those caused by the deterioration of materials. In particular, to ensure the continuity of the service it is essential to know the status of the conductors, supports, insulators, pole-mounted transformers and other components.

Performing the inspection activity in this area can be dangerous for people who usually have to go near the lines. furthermore the costs can be significant and it is often necessary to interrupt the supply of electricity in the section concerned for obvious safety reasons.

To remedy and mitigate most of these problems, it is interesting to use industrial APR (Remote Piloting Aircraft) for the inspection of power lines.

1) Mitigate the risk for control personnel, who usually travels near high-voltage lines
2) Mitigate the costs of preventive, planned or extraordinary inspection
3) Mitigate the time needed to identify the problem
4) Provide real-time feedback regarding the maintenance status and conditions of use of the pylons and their critical components
5) Checks with high detail every single electrical part, joints, insulators, state of the materials, weeds or other undesired situations
6) Keep at a safe distance by operating with a stabilized 30x optical zoom, providing completely stable and high definition videos, from which you can also obtain individual frames
7) Check the maintenance status of the conductors, supports, insulators and transformers on trusses
8) Guarantee the continuity of the electricity service provided

This type of control takes place with live electric lines, that is without resorting to any interruption of the service and therefore without any inconvenience to the customers.

DOUBLE CAMERA

A thermal imaging camera for the purpose of identifying the presence of any “hot” points, such as for example the contacts of the isolators, the electrical terminal blocks at the connection points between the overhead line and those in cable, etc. These points obviously represent an anomaly in the correct operation of the component being measured, which in many cases results in a possible loss of electrical energy or worse still in a possible interruption of electrical connection, should the component be damaged further.

A camera with 30x optical and 6x digital zoom (180x overall) for an analysis of the state of the line, such as the deterioration of the isolators, poles, armament, ground, protection devices against overvoltages as well as the conditions of the pole transformers, conditions outside of the cabins, presence of plants near the line.

The customers and professional technicians of the Electricity Supplier are provided with geolocated photo-frames related to both compliant and non-compliant details as well as certified thermographic analyzes which, through evaluations and estimates, can plan any interventions to be implemented.

THE ELECTRODUCT: BRIEF HISTORY

The power line in electrical engineering is a network infrastructure designed to transport high voltage electricity. They have strongly variable characteristics, depending on the operating voltage and if the transmitted current is in direct or alternating current.

The overhead power lines are made up of lattice or tubular supports made of metal, designed to keep the conductor in tension (the metal cords) at a height from the ground sufficiently high to ensure electrical insulation and to respect the limit values ​​of the electromagnetic fields to soil.

The height of the lattice depends on the operating voltage, the medium voltage power lines usually have lighter supports and reduced height.

An overhead power line is composed of a series of elements that can be globally divided into “supports”, “conductors” and “equipment” (isolators, terminal blocks, horns and / or spark-gap rings, anti-vibration devices), which are constantly stressed, which is why it is important to always know the state to guarantee continuity of service.

SUPPORTS

For low and medium voltage lines the supports consist of simple poles in wood, steel or centrifuged reinforced concrete. The pylons are used in the high and very high voltage lines.

The trusses are reticular structures made with galvanized steel sections with L or T sections. This type of structure allows the quantity of metal used to be reduced to a minimum, offering low wind resistance and reducing the visual impact of the structure.

The part of the energy conductor between two supports is defined as “span”.

Each support consists of:

  • foundations: underground part in steel and concrete;
  • trunk or trunk: vertical part;
  • shelves: parts of the support that project transversely with respect to the shaft, to which the conductors are connected (through the interposition of the insulators);
  • cimino (or cimini): upper vertical protrusions, made to connect the guard rope to the support high enough to shield the conductors from direct lightning.

THE CONDUCTOR

The conductor is that metallic rope present between one support / trellis and the other. The greater the current to be transported, the greater the cross-section of the conductor, which is why aluminum is used as a material which, although it has a lower electrical conductivity than copper, is also characterized by lower density and cost.

Furthermore, less weight would guarantee less effort for the isolator and the support itself.

The weight of the spans (the stretches of conductor suspended as a catenary between two successive supports), generally between 200 and 1,000 meters, gives rise to pitches of several tons in the conductors, therefore the conductors are almost always made of bimetallic cords composed of wires of steel. The use of a bimetal rope allows to enjoy the high conductivity of aluminum and the high mechanical strength of steel.

THE GUARD ROPES

The guard ropes act as lightning rods for the underlying energy conductors and are mechanically and electrically connected to the supports, which are in turn singularly grounded. The guard ropes therefore, in addition to constituting a direct protection from lightning strikes, they put in parallel the electric supports of the power line, reducing the overall earth resistance of the line.

OUR PAST EXPERIENCE

More than 25 years in the use of industrial sensors and recently (last 5 years) sensors mounted on the drone, in collaboration with RINA.

Many of the power lines to be inspected can be quite simple, thanks to the possibility of approaching near the tower and taking off without difficulty from the ground but a lot depends on the context of the mission (difficulty of reaching or approaching the area of operations) and the need to request any NOTAM.

OUR CURRENT EXPERIENCE

Recently we use UAV DJI Matrice 210 RTK for the possibilities that this means during inspections of the pylons. Thanks to the easy integration of multiple payloads, such as thermal imaging camera and optical camera with both stabilized zooms, it is possible to obtain a high definition image while maintaining a safety distance of 15 meters from the tower. Its compactness allows it to be carried in a practical suitcase, with everything inside it (radio control, batteries, rooms, etc.)

Moreover, thanks to the various proximity sensors and the precision of the telemetric data it will be impossible to impact against any obstacle.

HOW WE CARRY OUT THE OPERATIONS

Take-off usually takes place in an area free of obstacles in order to reach the pylon that must be at a maximum distance of 500 meters. Position the drone in hovering with the diagonal bow to the truss so that all the components can be seen in detail on the sky and without the pylon disturbing the image too much and can confuse any anomalies. After that, with the thermal chamber, the presence of any hot spots is checked to indicate any anomaly to the insulators. With the use of zoom optics, a visual inspection of any rusting, breakage, etc. is then carried out. of every single component, such as bolts, condition of the pylon material, possible nests, etc.

CONTACT US FOR A QUOTE

TEL. +39.039.59.69.8.62
FAX. +39.039.92 20.984
EMAIL: contact@sky53.com