Partial discharge (PD) in electrical grids is a localised electrical discharge that only partially bridges the insulation between conductors, without causing a complete breakdown.
It typically occurs in high-voltage systems, such as power grids, transformers, cables, or switchgear, where the insulation is subjected to strong electric fields.
Javier Ortego, director of BlueBox Technology at Ampacimon, explains how PD can be detected:
Partial discharge monitoring can be applied to assets running at voltage of 1 kV or more can be applied at any stage of an asset’s life, even during commissioning.
However, it is particularly relevant to older assets that are at a higher risk of failure, especially those elements that are system-critical and which need to be rigorously monitored.
Key methods of monitoring
There are two ways of monitoring partial discharge events, off-line when the line is not energised, or online when the line is in use.
Off-line monitoring can take place during commissioning or if the line is de-energised when there is no load and therefore no noise.
Because the line is in use, online measurements can be more challenging as signal noise is generated that can interfere with the accuracy of any measurements.
For example, high-intensity noise can obscure the pulses derived from small partial discharge problems and make them difficult to detect.
In addition, it can make it harder to pinpoint the location of a particle discharge even if it is detected, the location is a key parameter to address any faults found.
There are also several possible monitoring strategies including punctual measurements that are performed at a specific time and usually last less than an hour, temporary measurements that can last perhaps hours or days and permanent measurements that monitor assets at all times and may be installed for months or years.
Finally, having obtained relevant data from the partial discharge monitoring, the interpretation of the signals is complicated and requires experienced personnel to derive actionable results.
This is the second part of Ortego's op-ed. Click here to read the last part.
How can we detect partial discharge in grids?
There are two ways of monitoring partial discharge events.
