Benefit of PD Measurement
  Failure rate minimization  

◎ Table I  Collected failure rate of different equipments

* : Data is collected from industries served by PDS, and on-line PDM was taken as a routine test since 2004.

  Cost of risk reduction  

◎ Table II  Benefit of risk reduction by on-line PDM

* : average amount of industries served by PDS.
** : minima production loss informed by customers.
*** : described in Table I 

  Life extension  

By time-based maintenance (TBM), the equipment would be replaced at the end of its lifetime expectancy regardless of its insulation condition. Once the insulation aging is slower than expectation (orange line in Fig. 1), the equipment is still replaced beyond its real poor insulation condition. By condition-based maintenance (CBM), the equipment would be replaced only if its insulation condition lowers than acceptance level. On-line PDM is one approach to implement CBM.

Fig. 1  Insulation aging v.s. different maintenance strategies