Hipot testing is primarily performed to make sure that high voltage insulation will hold up during service. Many equipment and plant owners share concerns regarding the possibility for causing damage or premature deterioration of insulation by performing hipot testing on their assets.
Although hipot testing is mandatory for generators by manufacturers, once the system is in place, generator owners have delayed testing the voltage to avoid possible breakdowns. Many companies have no issue with checking brand new machines and coils using the hipot test process, as this quality assurance in new equipment enables easy acceptance by the purchaser. However, for existing machinery and electrical equipment, there is a school of thought that other tests like insulation resistance and polarization index testing should be completed to detect system flaws before using high potential test procedures.
The truth is that hipot tests conducted for general maintenance are designed to stress the insulation relative to it's specified operating characteristics. The insulation of energized electrical system components are designed to withstand a measure of electrical stresses. High Potential testing, especially when combined with Tan Delta or Partial Discharge test equipment, can be used as a predictive or diagnostic tool. By doing so, considerations can be given to the the timing of maintenance or replacement of specific assets.
Insulation testing is by definition a method of minimizing electrical failures and unplanned outages. Routine electrical maintenance measures the health of electrical insulation and helps to keep equipment running smoothly. Additionally, it is designed to safely diagnose and identify conditions that could potentially threaten the safety for operators and the life of the electrical equipment.
Related electrical test equipment available for rent from Protec:
Editor’s Note: This post was originally published August, 2011 and has been updated freshness, accuracy and comprehensiveness.