Overview & Testing Scope
Electrical testing and commissioning is the vital bridge between equipment installation and safe, reliable system energization. At VOLTCORE Engineering Solutions, our field testing engineers utilize calibrated, precision laboratory-grade instruments to evaluate every electrical asset under realistic and simulated fault conditions.
Whether commissioning a newly constructed 33/11kV or 11/0.415kV industrial substation, retrofitting existing switchgear, or conducting routine statutory compliance audits, our systematic testing protocols detect manufacturing defects, insulation deterioration, installation errors, and wiring discrepancies before electrical power is applied.
Core Equipment Diagnostic & Testing Capabilities
Our on-site field testing services cover the entire power distribution chain with dedicated test procedures:
1. Power & Distribution Transformer Testing
Conducted strictly in compliance with IEC 60076 and BDS-1081 standards:
- Insulation Resistance (Megger Test): HV to LV, HV to Earth, and LV to Earth using calibrated 2.5kV/5kV digital insulation testers.
- Transformer Turns Ratio (TTR): Precision ratio verification across all tap positions to ensure correct voltage transformation and detect winding short-circuits.
- Winding Resistance Measurement: Four-wire Kelvin bridge measurement to detect loose internal connections, broken strands, or high-resistance joints.
- Insulation Oil Breakdown Voltage (BDV): Dielectric strength test conforming to IEC 60156 standards (minimum 40kV to 60kV threshold).
- Magnetic Balance & Magnetizing Current: Assessment of magnetic core symmetry and detection of inter-turn insulation faults.
- Vector Group Verification: Confirming phase displacement (e.g. Dyn11) for parallel operation compatibility.
2. HT & LT Switchgear / Circuit Breaker Testing
Ensuring reliable fault clearing and mechanical endurance for Vacuum Circuit Breakers (VCB) and Air Circuit Breakers (ACB):
- Contact Resistance (Micro-Ohm Test): High-current DC injection (100A+) to verify primary contact resistance and detect pitting or oxidation.
- Breaker Timing & Synchronization Test: Measuring close, open, and close-open operating times and pole discrepancy.
- Vacuum Bottle Integrity Test (Hipot): High-voltage AC withstand test across open vacuum interrupter contacts to verify vacuum retention.
- Insulation Resistance of Busbars & Cubicles: Phase-to-phase and phase-to-ground dielectric integrity check.
3. Protective Relay Calibration & Secondary Injection
Protecting multimillion-taka industrial assets from catastrophic short-circuits:
- Secondary Current Injection Testing: Testing pickup thresholds, operating time curves (IDMT / Definite Time), and instantaneous elements.
- Protection Schemes Verified: Overcurrent (50/51), Earth Fault (50N/51N), Differential (87T), Master Trip (86), and Undervoltage/Overvoltage (27/59).
- Instrument Transformer (CT & PT) Testing: Ratio test, polarity / vector check, winding resistance, and excitation knee-point curve verification.
4. Power Cable Testing & Earth Resistance Auditing
Validating underground and riser cables and grounding networks:
- VLF Hipot & Insulation Resistance: Very Low Frequency (0.1Hz) AC Hipot test for 11kV & 33kV XLPE cables to verify dielectric strength after trench pulling.
- Phase Sequence & Continuity: Validating end-to-end cable phase identification and armor grounding.
- Earth Electrode Resistance (Fall-of-Potential): Measuring individual earth pit values and combined substation mesh ground grid resistance (< 1.0 Ohm target).
Regulatory Standards & Utility Approvals
All testing methodologies adhere strictly to national and international engineering benchmarks:
Documentation & Client Deliverables
Upon completion of field testing, clients receive a comprehensive engineering handover package:
- Certified Test Reports: Detailed asset-by-asset test sheets signed and stamped by certified electrical engineers.
- Relay Setting Schedules: Documented coordination curves, pickup values, and time multipliers.
- Punch List Resolution: Identification and remediation of pre-energization non-conformances.
- Utility Clearance Support: Direct technical coordination with distribution utility inspection teams for final energization approval.