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Using Partial Discharge Activity Data

Partial Discharge measurement is a useful technique for assessing the condition of individual assets, but it is of far greater value when applied to groups of assets – for example a substation or an entire network.

Condition data based on Partial Discharge measurement may be applied at several levels:


Basic Partial Discharge detection and measurement instruments are used to indicate the presence and severity of Partial Discharge activity in multiple assets. This is often a valuable basis for more intensive surveys and data gathering.


More sophisticated instruments are employed to locate precisely, measure and record PD activity in multiple assets. The data collected from such surveys are interpreted by experts to provide valuable management reports.

This is the foundation of true condition based asset management, providing the information needed to develop registers of assets, including:

  • Current condition and ‘health indices’ for each asset
  • Timeline predictions of likely failure
  • The ability to prioritise and schedule maintenance and replacement


PD activity inevitably changes over time and as a result of changes in environmental conditions, including temperature and humidity.

Partial Discharge monitoring systems are employed, either temporarily or permanently, to provide the most detailed assessments of the condition of assets – particularly those where there are histories of problems, or where failure would have unacceptable consequences. Again, expert interpretation of the data gathered provides the most valuable management information.

PD Activity Data
Accurate measurement of Partial Discharge Activity can be one of the most valuable keys to understanding the true condition of assets

Partial Discharge Data Interpretation

Measurement of Partial Discharge activity can be interpreted in several ways:

  • Expert training is available to help operators use Partial Discharge measuring instruments and interpret Partial Discharge activity readings.
  • More advanced instruments for measuring and monitoring PD activity are bundled with analytical software, which automatically provides operators with reports and recommendations on asset condition.
  • Remote monitoring, analysis and reporting services are available on a contract basis from specialists, who will provide detailed interpretation of PD monitoring results.

Condition Based Risk Management (CBRM)

The ability to assess the condition of live assets by measuring Partial Discharge activity is one of the principal foundations of Condition Based Risk Management (CBRM).

CBRM takes condition-based asset management to the ‘next level’ by factoring in risk i.e. both the probability and consequences of asset failure. It is a comprehensive management methodology, which enables operators to optimise the management of their entire asset portfolio and make more intelligent investment decisions on asset replacement, based on actual condition.

CBRM uses condition data to develop health indices for
assets and calculate the probability of their failure.