Technological progress in MV grid automation was forced by the legislator, introducing progressively more restrictive regulations concerning allowable duration of interruptions in power supplied to customers.
The obligation to publish MAFI, SAIFI and SAIDI indicators has caused the need of increased expenditures on MV grid automation.
- SAIDI - system average interruption duration index (for long and very long interruptions)
- SAIFI - system average interruption frequency index (for long and very long interruptions)
- MAIFI - momentary average interruption frequency index (for momentary interruptions)
Average times for locating faults on MV overhead lines
- Without switch disconnectors with a remote control system: about 3.5 hours,
- Switch disconnectors with a remote control system: about 30 minutes,
- Switch disconnectors with a remote control system and short-circuit indicators: about 15 minutes,
- Reclosers operated by radio control with protection automation: approx. 5–8 minutes,
- Reclosers operated by radio control with full protection automation, operating with radio control switch disconnectors with protection automation < 3 minutes.