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Tests and Analyses
Transformer and breaker tests, oil analyses, LVD electrical safety tests and rack static calculation. Measurement-based engineering reporting.
Our testing and analysis services cover engineering works in which the condition of electrical equipment and load-bearing structures is quantified through measurement and testing. Complementary to periodic inspections, these analyses generate numerical data for pre-failure warning, preventive maintenance planning and investment decisions.
Main Headings
- Tests and Analyses of Transformers and Transformer Circuit Breakers — dielectric strength, acidity, moisture and dissolved gas analysis of insulating oil; relay and contact examinations; cell tests.
- PL Analysis and LVD Tests — insulation, high voltage, leakage voltage and earth continuity tests of machinery and electrical equipment.
- Rack Static Calculation Analysis — determination of the load capacity of existing racking systems through calculation and measurement.
Why Tests and Analyses?
Visual examination reveals the visible condition of equipment; however, ageing of insulation paper, rising moisture in oil or loosening of connections becomes visible only through measurement. Polarisation index (PI) and dielectric absorption ratio (DAR) determinations quantify the moisture/contamination status of windings, while dissolved gas analysis (DGA) flags internal fault types (discharge, overheating, arcing) at an early stage. Thus the maintenance to be performed in planned shutdowns is scheduled before a failure occurs. For racking systems, the static calculation analysis exposes the risk of collapse due to design error or overload in a calculation-based manner.
Measurement and Testing Methods Used
The main methods we apply in the field and in accredited laboratory environments: megger (insulation resistance) and PI/DAR tests, dielectric breakdown voltage measurement, moisture determination (Karl Fischer), acidity (titration), DGA (gas chromatography), secondary injection tests of protection relays, earth resistance (fall-out-of-potential) measurement, contact resistance (micro-ohmmeter) measurement, thermographic scanning and ultrasonic leak/partial discharge listening. All results are compared against the acceptance limits of the relevant standard and coded as compliant/non-compliant in the report.
To decide which analysis set your facility requires and to schedule the measurement periods, you may consult our expert team via our contact page.
Analysis Frequency and Evaluation Criteria
The period of tests and analyses is determined by the criticality of the equipment, the operating regime (continuous or intermittent), ambient conditions and historical measurement trends. While gas analysis of critical oil-filled transformers is typically repeated at 6-12 month intervals, the same trend data also forms an input for maintenance budgeting. In the evaluation, the rate of change between consecutive measurements is used as the basis rather than a single reading; a falling trend in insulation resistance, rising moisture or increasing contact resistance is interpreted as a failure precursor.
In the final report, every parameter is presented together with the measured value, standard reference, threshold and compliance code, enabling facility decision-makers to build budget and shutdown planning on data. This trend-based approach is the foundation of predictive maintenance programmes: intervention before a failure occurs defers unplanned downtime costs and premature replacement investment. When the results are interpreted together with the findings of our periodic inspection services, a holistic equipment health picture of the facility emerges.
FAQ on Tests and Analyses
Tests and analyses of transformers and transformer breakers (oil dielectric strength, dissolved gas analysis, moisture, acidity, density, viscosity, particle count, Buchholz relay, thermometers, bushing and insulation checks, winding and contact resistance), electrical installation tests (earthing measurement, residual-current device trials, thermal camera) and electrical device tests under the Low Voltage Directive (isolation, high voltage, leakage voltage, earth continuity). Rack static calculation analyses also sit in this heading.
Periodic inspection is the compliance surveillance mandated by law: it verifies with documents that the equipment works within safe limits. Tests and analyses are diagnostic measurements revealing the electrical and chemical condition of the equipment — producing trend and fault risk. They complete each other: oil and gas analysis flags a transformer fault before it happens while the annual inspection carries the conformity record; a healthy OHS regime runs both together.
Dissolved gas analysis (DGA) separates partial discharge, overheating and arcing faults from gas fingerprints such as H2, CH4, C2H2, C2H4 and is interpreted with the IEC 60599 classification; dielectric strength and moisture show the insulation margin while acidity shows oil ageing. Besides the annual routine sample, re-sampling after a fault, relay trip or abnormal operation is recommended. Results must be evaluated as a time-series trend, not a single snapshot.
Yes. Every measurement is recorded together with its limit values and reference standard; findings are classed normal-caution-urgent and the corrective action suggestion (oil change, drying, torque-tap maintenance, part replacement) enters the report. First test values form the reference baseline for later analyses. On request, an annual test-analysis calendar is set up per your equipment inventory and coordinated with the periodic inspection regime.