As part of our ongoing mission to deliver innovative drone-based solutions to our clients, Silver Spectrum Solutions is investigating the use of drone technology for creating digital twins of physical plant equipment. Digital twinning is fast becoming a major new approach to design and maintenance in the 4th Industrial Revolution (4IR) and is assisting in connecting the physical world to the digital.
We have recently implemented technologies that integrate big-data processing, machine learning (ML) and remote sensing to create digital twins of high voltage transmission pylons. We intend using the digital twin to assist with predicting potential problems before they become critical and to generate automated notifications. This application for power line pylons is merely the first low-risk proof-of-concept project that we have completed. This project also allowed us to conduct an ‘as-built’ study for our client, which involved comparing the dimensions of the existing structure to its design. Our future plans include the digitisation of power generation plants with the aim of improving productivity and transforming the full product lifecycle thereof.
THE PROOF-OF-CONCEPT PROJECT
For this project, we investigated the complexities of digitising a 275 kV metal lattice structure (shown in Figure 1). A three dimensional (3-D) model of the structure was generated using a technique called digital photogrammetry. Our client has permitted us to release some basic information relating to the study.
Figure 1: The structure that was investigated
A total of 70 images of the structure were taken from different oblique angles around the structure (see Figure 2). Our software was used to recreate the digital software model of the structure (shown in Figure 3). The imagery was captured at various altitudes and a final ground sample distance (GSD) of 2.74cm/px was achieved.
Figure 2: Flight path around the structure showing locations where images were taken
PYLON STRUCTURE ANALYSIS
Several analyses were conducted using the digital twin. Figure 3 shows the resultant 3-D model. Having the structure represented in 3-D space allows for accurate measurements taking into account sag due to the weight of the conductors etc. The model is available in many popular computer-aided design (CAD) model formats including OSGB, PLY, OBJ and LAS.
Figure 3: Software model of the pylon
The scan data was further augmented and its accuracy improved by setting out ground control points around the structure. Since the model was adjusted for precise location in 3D space, we were able to use our software to measure various parameters such as midspan clearance, conductor bundle sag, insulator connecting length, lightning shielding angle, phase-to-phase distance, clearance to earth wire and pylon leg spacings, amongst other parameters. Figure 4 shows the measurement of the insulator connecting length.
Figure 4: Insulator Connecting Length
A manual correlation showed that the connecting length was as per the design. The level of detail obtained from the images allows for the ability to count the number of individual insulators used. Figure 5, shows the measurement of the phase-to-phase spacing. Our measurement indicated that this was as per the client’s design.
Figure 5: The phase to phase distance measurement
The aerial data was also used to calculate other basic parameters such as the pylon leg spacing distance.
Figure 6: The pylon leg spacing
The imagery data was also used to generate a point cloud. Figure 7, shows the resultant point cloud model.
Figure 7: Point cloud model
The point cloud data provided a more accurate solution for finer elements such as shield wire detection. Using this data and basic trigonometric calculations, the shielding angle was verified for our client. This was possible as we were able to measure the offset between the phase bundle and the shield wire in both the horizontal and vertical axes.
This initial proof-of-concept was a success and shows yet another use case for drones in the 4th Industrial Revolution.
Silver Spectrum Solutions can assist you in conducting similar digital twinning digitisation using drone technology. For more information on this or any of our other projects contact Akshar Rampath on (cell) +27 83 554 9197.