At first glance, over-head powerline maintenance inspections appear to be identical all over the world. A closer look reveals numerous variants, which derive from local contexts and regulations, “heritage” practices, economical, labour and environmental concerns. Nevertheless, there is one common desired feature: integration of multiple inspections in one single pass for the benefit of analysis insight as well as operational cost savings. This paper describes the issues encountered while analysing client requests and wish-lists in order to devise integrated inspection solutions that fit individual grid contexts in different countries.
This paper focuses on medium voltage (> 1kV) and higher voltage over-head line (OHL) inspections, considering both ground inspections and airborne inspections with emphasis on the latter. Inspection needs depend on the influence of regulators and markets, grid size and density, average energy consumption or revenue per client. As a consequence, inspection reporting requirements may include a wide range of data, from qualitative evaluation of assets to geographic information system databases updated in near real-time. The needs for visual, thermography, corona effect inspections are addressed and operational conditions associated to each sensor are mentioned. A special emphasis is put on track clearance (= right of way) and environmental assessment. For the sake of efficiency, the whole inspection work flow is considered: upstream (planning and inspection optimisation) and downstream (data processing, database integration, feeding data to field teams).
Compromises arise during design definition and justification of a new solution for OHL inspections, beginning with the economical competitiveness criterion. Furthermore, the migration or upgrade from older systems already in operation imposes compromises between optimal performance and convenience. The integration of multiple features in one inspection and the flexibility to operate in different scenarios adds further constraints. Finally, safety, reliability and confidence of the inspection personnel are required to ensure efficient operation.
These constraints are evident on design requirements made by operators from four different continents and shape the inspection solutions proposed for Brazil, Spain and Portugal. In spite of technical, economical and cultural affinities, differences are apparent and illustrate the need to encompass local requirements to find unique optima for each client.