CONDITION MONITORING SERVICES
Thermography - ONLINE
Non-contact, non-destructive online method detection on invisible infrared thermal radiation of objects. Any thermal anomaly may result in failures. Anomaly is based on detection of temperature difference of standard guide, phaseto-phase temperature differences and operating temperature signatures.
Insulation Resistance - OFFLINE
The insulation resistance test provides useful indicator of contamination and moisture on the insulation surfaces of the winding, especially when there are cracks, pinholes or fissures in the insulation.
Turns Ratio - OFFLINE
The winding turns ratio test is useful to determine whether or not there are any shorted turns or open winding circuits in the transformers.
Winding Resistance - OFFLINE
The winding resistance measurement allow the detection of the subtle changes in conductor resistance caused by various types of damage, i.e. high resistance joints, corrosion, fractures or dimensional reductions in the cross sectional area of conductors. With time in service, the mechanical vibration of operation can lead to failure or partial failure of conductors. Insulating blocks can also vibrate and wear away part of the cross section of copper conductors.
Excitation Current - OFFLINE
Excitation current measurements provide means of detection of extensive core problems, like shorted lamination or winding problems, partial or high resistance short circuit between turns, poor joints or contact etc
Insulation Power Factor (Dielectric dissipation factor / Tan Delta Measurement) - OFFLINE
The dielectric power factor is a property of the electrical insulation system and a measure of the electrical losses in the insulation. Measurements are made on each winding to ground and each winding to all other windings in the transformer. Current leakage through the insulation is measured and the power factor calculated as the ratio of the watts-loss to the apparent power input. The measurement is of value in diagnosing degradation and deterioration of the insulation system.
Frequency Response Analysis - OFFLINE
Frequency Response Analysis is a diagnostic tool that is used to help identify possible deformations and movements in the transformer’s core and coil assembly and other internal faults. The movement or distortion of the winding or lead structure of power transformer can take place due to short circuit forces, or loss of rigidity and tightness associated with shrinking caused by ageing of insulation. This can result in a transformer fault that will cause damage to the transformer and may result in explosive failure of the transformer.
On-load TAP Changer Diagnostic - ONLINE / OFFLINE
Using combined vibro acoustic and motor current measurement, condition of tap changer in operation can be monitor and diagnose. The vibration and the arching can be measured synchronously to detect most of common OLTC malfunctions – contact wear, arcing in diverter, arcing in selector, synchronism problem, drive mechanism problem, brake failure etc. Measurement can be conducted during online and offline non destructively.
Frequency Domain Spectroscopy / Dielectric Frequency Response (DFR/FDS) - OFFLINE
Measurement of the transformer frequency domain spectroscopy was performed on each winding to ground and each winding to all other windings in the transformer. The current leakage through the insulation is measured and the dissipation power factor over a broad range of frequencies from a low to higher frequencies is plotted to evaluate the condition of the insulation system.