EN
Medium Voltage Systems Testing and Commissioning
MV testing and commissioning: equipment diagnostics, relay injection settings, interlock scenarios, energisation procedure and distributor acceptance.
Medium voltage systems testing and commissioning is the end-to-end verification of the installed MV facility — cells, transformers, cable routes, protection relays and control circuits — before energisation and its controlled handover to operation. Commissioning is a risk management procedure, not a checklist: the first energisation is the design's first exam against fault current, and if protection is not set correctly the system closes the exam with damage. KYF Test runs diagnostics, setting verification, scenario testing and the stepped voltage application discipline under single responsibility.
Test Cascade
- Equipment diagnostics: Type-character tests per unit — contact resistance, insulation (IR-PI-tan delta), TTR-DGR, timing; oil-DGA analysis and mechanical locking-function checks (our cell test and transformer test pages).
- Instrument transformer chain: CT-PT polarity-ratio-saturation with secondary circuit continuity-burden verification — the spine between metering and protection.
- Relay injection: Overcurrent, thermal capacity, earth-fault, neutral and differential stages verified against the setting list in phase-phase and phase-earth fault models (IEC 60255 curves); sequence-of-operations (SoO) testing covers breaker trip-close and auto-reclose restraints.
- Control and SCADA: Remote control-locking priority matrix, telemetry correctness, alarm-log continuity and NTP synchronisation.
Energisation Scenario
The order of applying energy manages risk: earthing and overvoltage protection with bonding continuity are confirmed first; unloaded cable-transformer sections are taken under voltage stepwise (percentage of nominal), magnetising current-voltage compatibility and phase rotation checked; in parallel transformers vector group and ratio difference (IEC 60076) are verified before loading. At load step transitions, the protection-metering chain is finally verified by primary injection. Every step progresses on signed records and a stop-root-cause rule applies on deviation.
Acceptance File and Corporate Process
The commissioning output is the acceptance package of single-line diagram, setting list, test protocols, cold-hot thermal photos, oil analysis, scenario records and the as-built file. Conformity to the distributor-approved design (project acceptance approval), provisional acceptance and operating licence steps run on this file. Periodic inspections are built on these reference values.
Legal Basis and Outcome
The process runs under Law No. 6331, the six safety rules and work permits of the High Current Installations Regulation, the Electricity Market Connection-System Usage regulations; technically TS EN 62271-100/-200, IEC 60255 (relays), TS EN 60076 and TS HD 633 S2. Dead-working security is held with lockout-tagout (LOTO) and switching instructions. Demand energisation safety for your MV field: contact page; this service sits under MV Contracting.
FAQ on MV Systems Testing and Commissioning
The first energisation is the plant\s first exam against fault current: if protection is not set right, the system closes the exam with damage. The service runs diagnostics (cell-transformer-cable tests), CT-PT spine verification, relay injection and control scenarios under single responsibility, step by step with signed records. Every phase has a written exit criterion; on deviation the stop-root-cause rule applies.
With an injection kit in phase-phase and phase-earth fault models, the overcurrent, thermal capacity, earth fault and differential stages are verified against the setting list using IEC 60255 curves. Sequence-of-operations (SoO) testing covers trip-close, locking-priority matrix, auto-reclose restraints and SCADA-telemetry-alarm-log integrity. The final verification at load steps runs by primary injection.
The order manages risk: first surge protection and earthing-bonding continuity (earthing control) are confirmed; unloaded cable and transformer sections are taken under voltage stepwise, magnetising current-voltage compatibility and phase rotation checked; in parallel transformers vector group-ratio difference verified before loading. Progress happens on signed steps under switching instruction, LOTO and the six safety rules regime.
The acceptance package of single-line diagram, setting list, test protocols (including cold-hot thermal photos), oil analysis, scenario minutes and the as-built file is the ground of conformity to the distributor-approved design (project acceptance approval), provisional acceptance and operating licence steps. Periodic inspections build on these reference values; the file is kept as the technical passport of the facility.