Power grid infrastructure is the most developed field of application for mobile inspection robotics. The inspection tasks are standardised, they recur frequently, and a considerable share of them consists of measurements that are carried out with instruments anyway. Three particularities distinguish grid operation from other industries: safety distances to live parts, a demanding electromagnetic environment and the classification as critical infrastructure.
Why this application leads the way
Three developments coincide.
The asset base is growing. Grid expansion, the connection of renewable generation and new battery storage systems significantly increase the number of sites to be looked after – without maintenance staff becoming available to the same extent.
Qualified electricians are scarce. Inspections of electrical installations may only be carried out by suitably qualified personnel. This qualification cannot be built up at short notice.
Many sites are unmanned. Every inspection means a journey. In a grid area with dozens of substations, this adds up to considerable travel time for comparatively short inspection activities.
This is exactly where the economic leverage lies: not in replacing personnel, but in relieving existing specialist staff of routine rounds and shortening inspection intervals without generating additional journeys.
Types of installation and their suitability
| Type of installation | Suitability | Note |
|---|---|---|
| Outdoor switchgear | high | standard case; check ground and weather |
| Indoor switchgear | high | good navigation conditions, mind narrow aisles |
| Converter station | high | large inspection scope, often unmanned |
| Cable tunnels and routes | very high | manual walk-through involves particularly considerable effort |
| Battery storage | high | growing field, thermography central |
| Hydroelectric power plant | medium | humid environment, some confined structures |
| Local substation | low | too small for a stationed robot |
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Inspection tasks
The following list is based on the typical inspection scope of an inspection walk-through. Almost all of it can be captured optically or thermally.
Thermal inspection
- terminal points and bolted connections
- disconnectors, circuit breakers, busbars
- current and voltage transformers
- cable terminations
- transformers and reactors
- auxiliary power distribution boards and battery rooms
Thermographic inspection is the most productive single area, because heating is an early and unambiguous indicator of developing faults – and because a repeatable series of measurements says considerably more than a single image.
Transformers
- oil level at the conservator
- oil leaks and condition of the oil collection pan
- colour of the desiccant
- position of protective devices and indicators
- fan operation and noise anomalies
Gas-insulated switchgear
- pressure indicators of the insulating gas monitoring
- visual inspection of the bushings
General plant inspection
- reading meters, pressure gauges and indicators
- insulators: contamination, damage, flashover traces
- earthing connections, visible corrosion
- condition of paths, gates and fencing
- vegetation and keeping safety distances clear
- foreign objects and unauthorised access
Supplementary
- partial discharge detection using acoustic methods
- noise anomalies on rotating equipment
Sensors
| Inspection task | Sensors |
|---|---|
| Thermography on equipment | thermal imaging camera, radiometric |
| Indicators, meters, labels | optical camera with optical zoom |
| Partial discharge | acoustic localisation |
| Insulating gas monitoring | optical reading of the indicator |
| Documentation, access logging | camera with position data |
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Two requirements are more specific here than in other industries:
Radiometric thermal image data. A sound assessment requires temperature values for each pixel, not just a false-colour image. Only then can limit values be applied and series of measurements compared.
Optical zoom with sufficient focal length. Equipment in outdoor installations must be captured from the permissible distance – digital zoom is not sufficient for this.
Particularity 1: safety distances
The most important difference from all other fields of application.
When operating electrical installations, defined zones apply around live parts: a danger zone, which may only be entered under special conditions, and an approach zone beyond it. The distances are voltage-dependent and tabulated in the relevant operating regulations.
Practical consequences:
The distances belong in the navigation map. Not in the user instructions, not in training material – as exclusion zones in the map, against which the system plans its routes.
The tolerance of the localisation is a safety parameter. If the system knows its position to within ±30 cm, this value must be taken into account in the safety distance.
The behaviour on loss of localisation must be defined. A system that keeps moving when its position is unclear is not acceptable in switchgear.
The height of attachments counts as well. A raised mast or an extended sensor carrier changes the relevant geometry.
Particularity 2: electromagnetic environment
Switchgear is one of the most demanding electromagnetic environments of all. In addition to the permanent fields, switching operations cause steep transient events.
For equipment used in power stations and switchgear, there is a separate generic standard on immunity – with considerably higher requirements than the general industrial standard of the EN 61000-6 series.
This is a specific checkpoint when selecting a supplier. Ask which immunity standard the system was tested against. A test according to the general industrial standard is not automatically sufficient for switchgear.
The behaviour on loss of the radio link must also be clarified – switchgear is not an easy environment for radio links.
Particularity 3: critical infrastructure
Operators of energy supply networks are subject to particular requirements for IT security. For electricity and gas network operators, German energy industry law requires an information security management system, whose requirements the Bundesnetzagentur (Federal Network Agency) has set out in a separate catalogue.
A network-capable inspection robot therefore falls within the scope of this management system. It is not a tool that is simply plugged in on the side, but a component that must be assessed and documented within the management system.
Questions you should put to the supplier:
- Which network connections does the system establish, and to which destinations?
- Can operation be carried out entirely without an external connection?
- How are firmware updates signed and verified?
- What access does the manufacturer have during regular operation?
- Is there an independent security test report?
- How are access authentication and logging handled?
For systems from manufacturers in third countries, there is the additional question of data flow and the applicable legal system. It should be answered in writing and verified in the acceptance test – for example by capturing network traffic.
Connection to existing systems
An inspection robot generates data. Its benefit only arises through processing.
Control system. If a finding is to trigger an alert, a defined interface is needed, as is a clear rule on which finding generates which alert. False alarms are the quickest way to make a system unusable.
Maintenance system. Inspection results belong in the same history as manual findings. Otherwise two separate data sets are created.
Thermography analysis. Radiometric data should be available in a format that works with your existing analysis software.
Clarify the interfaces in the requirements specification. Integration after the fact regularly involves more effort than assumed.
Cost-effectiveness in grid operation
The most robust items in this industry:
Journeys no longer needed. At unmanned sites, the most reliable figure – travel time, kilometres, working time of a specialist.
Shorter inspection intervals. Weekly instead of monthly thermography without additional staff deployment changes early fault detection considerably.
Condition-based instead of interval-based maintenance. Continuous series of measurements are the prerequisite for aligning measures with the actual condition rather than the calendar.
Avoided outages. A fault on a piece of equipment detected in time may prevent a supply interruption. This item is the largest in economic terms and at the same time the hardest to substantiate – it should be shown as a range, not as a point value.
Typical pitfalls
The charging point must be within the installation. Substations are locked; a device that has to be brought along for every inspection round generates exactly the journey that is meant to be saved.
Qualified electrician status. Clarify early on what qualification the person needs who sets up and looks after the system and assesses the findings.
The operating instructions must be adapted. A system moving independently in an electrical installation is not provided for in existing operating instructions.
Winter operation. Cold reduces battery capacity considerably – the stated runtime applies to moderate temperatures.
Substation site assessment
- Safety distances taken from the operating instructions and marked on the site plan
- Charging point possible within the installation, power connection available
- Ground along the planned route assessed, gravel tested in trial operation
- Immunity standard of the system requested from the supplier
- Behaviour on loss of localisation and loss of radio link defined
- Zone-classified areas identified, in particular battery rooms
- Network connection assessed in the information security management system
- Interfaces to control and maintenance systems clarified
- Responsibility for set-up and assessment of findings assigned
This checklist will be offered as a download once the template exists.
Sources
- Energiewirtschaftsgesetz Bundesministerium der Justiz accessed 15 August 2026
- IT-Sicherheitskatalog für Strom- und Gasnetzbetreiber Bundesnetzagentur accessed 15 August 2026
- Technische Regeln für Betriebssicherheit Bundesanstalt für Arbeitsschutz und Arbeitsmedizin accessed 15 August 2026
Change log (1)
- 5 October 2026 Initial publication First publication of the English version.