Hello Sir / Friends,
We @ System Protection bring at your doorstep a break-through technology in detecting electrical insulation failures before they occur, this will not only ensure a reliable Power System but will help safeguard your Men, Machine and thus Production and Revenue.
Case Study of 11 kV Switchgear - Damage was found before it could turn into an accident (See the main Photo)!
85% of disruptive failures in HV/MV assets are related to Partial Discharge (PD) activity. The most advanced TEV + HFCT + AA Sensors coupled with intelligent ****ytics Tools accurately provide early warning against incipient faults in HV Networks.
What is Partial Discharge (PD) and why should we test for it?
PD is an electrical discharge that occurs across a localized area of the insulation between two conducting electrodes, without completely bridging the gap. It can be caused by discontinuities or imperfections in the insulation system.
PD testing gives an indication of deterioration of the insulation and is an indicator of incipient faults. In general, PD will occur in systems operating at voltages of 3000 V and above; it should be noted though that in some cases PD can also occur at lower voltages.
Where does PD occur?
PD can occur at various points in the insulation system, for ex: voids in the insulation medium, at the interface between insulation layers or in gas bubbles in liquid insulation.
PD activity can start under normal working conditions in high‑voltage equipment where the insulation condition has deteriorated with age or has been aged prematurely by thermal or electrical over-stressing, or due to improper installation
Causes of Partial Discharge:
Voids within the solid insulation.
Contamination by particles on the surface of the insulating material.
Irregularities (e.g. sharp points) on the surface of an insulating material.
Gas bubbles in liquid insulation.
Floating particles in gas insulation.
Discharges around an electrode in gas (corona activity).
Mechanical failure or damage to insulation materials.
Partial Discharge activity is also affected by environmental factors, including temperature and humidity.
Online Partial Discharge Testing:
PD testing of MV and HV plant gives an advance warning of pending insulation failure, allowing the team to take remedial maintenance action during planned outages. Our past projects have shown that in general the earlier the advance warning can be made, the cheaper the maintenance or intervention costs will be.
PD testing and monitoring give an accurate picture of the HV plant's health and performance under normal service conditions, including the effect of load, temperature, and humidity.
PD Testing is one such maintenance activity which is followed worldwide in plants. It is recommended for HV / MV Switchgear (Panels), Switchyard, Transformers, Cables, Motor and Generators whose running life is more than 5 years.
If PD Testing had been done at correct time, below breakdowns could have been avoided
Partial Discharge activity provides clear evidence that an asset is deteriorating in a way that is likely to lead to failure. For example, PD activity in voids in insulation causes erosion, which leads to increased PD activity.