Scope
- Contract and registration: registration of the operation responsibility contract with EMO and notification to the distribution company.
- Site checks: transformer (oil level and temperature, breather, leaks), MV switchgear, disconnectors and circuit breakers, protection relays, earthing connections; operation log entries.
- Switching and safety: written switching instructions, lock-out and tag-out arrangements, an up-to-date single-line diagram at the switchboard, checks of insulating equipment and personal protective equipment.
- Faults and outages: coordination with the distribution company and controlled re-energisation after a fault.
- Measurement plan: scheduling of earthing measurements, thermal imaging checks and transformer oil analyses.
- Changes to the installation: design and application processes for capacity increases and new transformers.
Method and instruments
Checks follow a standard checklist; every visit is entered in the operation log and findings are shared with photographs.
Hot spots at transformers, switchgear and connections are measured with the Bosch GTC 400 C thermal camera and earthing with the Kyoritsu KEW 6516BT.
For facilities using the Energy Monitoring Portal, demand and reactive ratios are updated every day from OSOS data and limit violations appear as alerts in the portal.
Regulations and standards
- Regulation on Heavy Current Electrical InstallationsOperation of HV installations and operation responsibility
- EMO Regulation on Operation Responsibility for High-Voltage InstallationsContract, registration and duties of the responsible engineer
- Regulation on Earthing in Electrical InstallationsMeasurement and inspection of earthing systems
- TS EN 50110-1Operation of electrical installations; safe working procedures
Deliverables
- Operation responsibility contract registered with EMO
- Visit reports and operation log entries
- Switching instructions and an up-to-date single-line diagram
- Annual summary: findings, corrected nonconformities, planned maintenance and measurements
Frequently asked questions
Who needs an HV operation responsible engineer?
Facilities connected to the distribution network above 1 kV with their own transformer substation. Distribution companies ask for the operation responsibility contract registered with EMO at the connection and energisation stage.
How often are site checks carried out?
The visit frequency depends on the capacity of the installation and the contract; the minimum conditions of the EMO regulation apply. We also attend faults and planned outages.
Who carries out switching operations?
Switching is carried out by trained and authorised personnel following written instructions. Critical operations such as planned outages, taking a transformer out of service and earthing are carried out under the supervision of the operation responsible engineer.