Inspection | Cutting diver risk
Deep Trekker explains how remote operated vehicles can help improve diver safety during underwater inspections within the hydropower industry
Right: An ROV equipped with sonar identifying a discarded tire during an inspection
References
www.academia.edu/27691526/ SURVEY_AND_ANALYSIS_OF_ FATAL_ACCIDENTS_IN_THE_ COMMERCIAL_DIVING_SECTOR
FOR OVER A DECADE remote operated vehicle (ROV) manufacturer Deep Trekker has been specialising in underwater inspections with its line of portable and affordable battery-operated inspection robots. Based in Ontario, Canada, the company offers three different ROV models to perform a variety of hydropower plant inspections. Deep Trekker’s DTG3 is an effective tool for quick inspections through low current conditions and confined spaces, says the compant. This compact machine offers HD photo and video at an approachable price point for operations that are just beginning their work with submersible robotics. Deep Trekker also offers the PIVOT and REVOLUTION ROVs which provide superior power and stability through currents and their advanced stabilisation systems allow for the integration of a wide variety of sophisticated inspection equipment. The PIVOT and REVOLUTION are both equipped with six powerful, magnetically coupled thrusters which enable lateral and vertical movements, as well as tilting tool platforms for add-ons like positioning systems, dissolved oxygen sensors, or sonars. Integration with high quality multibeam imaging sonars like the M3000D allow the ROV to see even in zero visibility conditions.
What are the advantages of using ROVs
Below: A REVOLUTION ROV deploying into a confined space
in hydroelectric inspections? Traditionally, inspections of hydroelectric turbines or water passages would have required a dewatering process for safety and access. Dewatering and scaffolding are extremely expensive and costly in terms of time and resources. Deep Trekker ROVs’ compact yet rugged design allows them to navigate through complex confined spaces without putting divers at risk or stopping operations to dewater. ROVs from Deep
Trekker have been used by OPG, Duke Energy, Hydro Quebec, and TVA to safely inspect runners, penstocks, submerged pipes, and transmission lines without the burden of dewatering.
Optimise diver missions If initial inspection uncovers a potential issue, divers
may be required to enter the water. Even against best efforts and precautions, whenever humans enter the water, accidents can happen. According to a 2016 analysis of fatal accidents in the commercial diving sector [1], over the past 40 years there have been 577 recorded fatalities in commercial diving, occurring at a rate in the US of 181 per 100,000. Averaging over one death per month, this places commercial diving as the most dangerous industry during the time of study. Differential Water Pressure (Delta P) has become a
growing concern for dive teams in the hydropower space after it has been identified as the cause of death for one in four diving fatalities. Drowning, equipment malfunction, and becoming trapped or crushed are other common causes. Underwater ROVs can quickly and safely provide
real-time pre-dive checks to provide critical information relating to dangerous work environments. The vehicle can also be equipped with accessories for simple mechanical work, cleaning, or water analysis to minimise required diver tasks. Alternatively, an ROV can also quickly be deployed alongside a diver to monitor their status as a method of communication with the topside team or provide sonar imaging through turbid conditions.
Reservoir, intake, and trash rack An ROV equipped with multibeam imaging sonar
can be used to identify damage to reservoir walls, assess the size, and with an underwater positioning system you can easily navigate back to the precise
26 | July 2022 |
www.waterpowermagazine.com
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