A large power generation company in Eastern Africa requested ASI to complete a remote inspection and survey of five of their power stations. To complete the work for all facilities and significantly reduce the cost, ASI scheduled a single international mobilization. With a great deal of planning and packing, the ASI crew set off for the excursion. A crucial step in preparing for international travel is becoming familiar with the climate and environmental factors that could be encountered. Since ASI’s work takes place on rivers and reservoirs, some of the primary concerns were crocodiles and hippos.
The scope of work required several inspection operations at each station to assess many underwater structures, such as intake screens, stoplogs guides, long tunnels, drop shafts, and stilling basins. All of these assets are critical to the continued operation of the facilities that provide electricity to over 20 million people.
To complete all projects, ASI provided a customized Falcon ROV with an integrated sonar survey package and inertial navigation system (a configuration known for its reliability). To further ensure success, ASI prepared an extensive kit of spare parts and tools so that all equipment to keep the operation alive was onsite and accounted for. A truck crane was utilized to remove covers and stoplogs, as well as to launch the ROV into many of the access locations. The long boom allowed personnel to keep a distance from the water in case any hazards were lurking below. Fortunately, the ROV wasn’t enticing enough to be of interest.
The crew spent hour upon hour and day after day working to complete the inspections. Below the murky water surface, even the smallest of anomalies was captured. In such environments, skilled sonar operators are proven to be essential to generate informative assessments.
The bathymetric data was collected from a surface vessel, supplied by the client, and equipped with ASI technology. After review of several boats, it was determined that the standards for “seaworthiness” were not quite on par with the crew’s experience. After many repairs, using epoxy for fibreglass and an arc welder for steel, a suitable survey platform was assembled.
Once again, skillful operation was key to completing comprehensive surveys. Having a second nature understanding of the equipment and methods allowed the operators to give concern to other challenges, such as motor failures and crocs that kept coming to investigate. The survey data was used to construct 3D models of the facilities’ various water control structures. By reviewing this data in comparison with as-builts, a good understanding of the plants conditions was established.
Even some areas that would typically be considered inaccessible were surveyed, proving the portability of the multi-beam sonar system ASI provided. In one location, the configured vessel was lowered over 20 meters by crane to reach a basin surrounded by jungle. At the next location, the entire boat and survey gear was hand-carried 300 meters down rocky terrain to access the stilling basin requiring assessment.
All in all, a repeatable assessment was completed utilizing remote systems and acoustic inspection devices allowing for detection of anomalies and their change over time. ASI’s remote systems allowed inspection and survey operations in locations that are inaccessible or unsafe for personnel. This method also allowed for inspections without dewatering, which would have posed grave risks to the infrastructure.
All collected data was backed up and reviewed for reporting at ASI’s office. The editing of field data is a crucial step for delivering comprehensive reports to the client. As a result, the real client (millions of residents dependant on the energy produced), has an operator with a good understanding of their infrastructure. This makes proactive scheduling a reality and ensures greater reliability of the assets. The ASI crew’s takeaway was another successful trip and first-person discovery of many of the great creatures with which we share our planet.