EN
Transformer Earthing Measurement and Other Transformer Maintenance and Inspections
Transformer earthing measurement and general maintenance: neutral-body resistance tests, connection audits and mechanical-sensor service, reported.
Transformer earthing measurement and other transformer maintenance and inspections verifies the transformer earthing system (body, neutral, equipotential bar, support-console) through measurement, and runs the mechanical, hydraulic, sealing and sensing-electrical maintenance deemed necessary in an integrated manner. Earthing is both the life safety layer limiting touch voltage and the reference potential on which protection relays operate correctly — slippage in its measurement and maintenance makes the whole protection coordination suspect. Earth resistance grows over time due to soil moisture regime, electrode corrosion and mechanical damage; an annual trend reveals this rise earlier than a one-off measurement.
Earthing Measurement Items
- Resistance measurement: Neutral-to-earth (earth electrode resistance) and service earthing measured by fall-out-of-potential (3-point) or selective clamp; in multi-electrode networks step separation follows the selective method. Results are evaluated against the limits of the Earthing Regulation (particularly LV/MV service conditions and the short-circuit current-protection relation).
- Continuity: Milliohm measurement of body-earth conductor and metallic services-structure bonds to the equipotential bar; condition of the earth conductor cross-section-corrosion and its mechanical protection (crush-break scan).
- Structural: Support-anchor bolts and chassis pads, vibration damping elements; tightness and torsion traces at conservator-radiator connectors.
Maintenance and Control Items
- Mechanical: Bung-gasket leakage remediation, fan-pump bearing-lubrication, on-load tap changer (OLTC) inspection-oil service and counter reading; crack-expansion supports.
- Hydraulic-oil: Level topping, leak point repair, combining oil conditioning decisions with oil tests; regaining thermal performance via cooler circuit cleaning (General Cleaning).
- Sensor-protection: Function tests of thermometer, Buchholz relay, gauge-level-alarm relays; SCADA-automation signal dialogue and timestamp control.
- Electrical: Insulation (PI/DAR) and bushing tests, earthing connection terminals (Terminal Inspection) and secondary injection protection dialogue.
Period and Outcome
Earthing measurement ties to the Earthing Regulation tables per facility class (broadly annual in explosive-flammable sites, biennially elsewhere); maintenance is planned yearly-multiyearly per the manufacturer service calendar and risk analysis. Work runs under de-energised permits and LOTO; findings convert into prioritised work orders. In earthing measurement, correct placement of test electrodes and the seasonal variation of soil resistance are accounted for; a suspicious high reading is not adjudicated until remeasured in dry season. The outcome is presented as a signed periodic inspection report with the measurement record (device-calibration), maintenance list and non-compliance-rectification table, presented in insurance and audit files. This integrated service sits in our Transformer Tests and Analyses heading; for investment and commissioning works see our Medium Voltage Contracting Services page, or contact us for your inventory programme.
FAQ on Transformer Earthing and Other Maintenance
Continuity-low-resistance measurement (milliohm; joint tightness-corrosion) of body-neutral-base to the earth bar-terminal, earth electrode resistance-rod method or clamp, loop impedance, step-touch voltage risk, lightning-arrester-earthing integrity, screen-armour earth connections, LV-MV-panel neutral bar bonding-equipotential bonding with earth bar-cable-terminal-bolt state-torque (earthing control). Results are referenced to limit standards (TS EN 62305-IEC-Earthing Regulation).
The general measurement period is the yearly periodic control package; but it is repeated after an overcurrent-short-circuit event, suspected break at the earth bar, flood-excavation-vibration, direct lightning strike, new-commissioning-change-renovation. Explosive-chemical-humid-coastal environments and critical facilities shorten the period. Measurement results are evaluated as a trend against last year values.
Oil level-leak-thermometer-Buchholz-bushing-cooler fan-pump control, gasket-seal, paint-corrosion scanning, torque verification, joint-terminal thermal measurement, cooler fin-air-water direction-radiator cleaning, tap changer operation-mechanical wear, panel-control-heater-humidity-alarm, earthing-bonding-joint-screening-environment protection (wire fence-overflow), fire-evacuation-water drainage channel-step-handrail-fire extinguisher, documents-capacity plate-manual-plate.
The report carries measurement values (earthing-insulation-thermal-torque-trend), finding level, replaced consumable-part, the next control calendar and suggestion; it is prepared with competent engineer signature-seal. Within the frame of Law No. 6331, the Internal Electrical, Earthing and Work Equipment Regulations and distributor specifications; Energy Ministry communiques (acceptance-periodic control-authority certificate) are applied. Records stay in the OHS-energy-insurance file and are presented in audits.