Partial Discharge Surveys - Level II

Once a potential insulation issue has been discovered during the Level I PD survey, further level II analysis is necessary to ensure that the “suspect” signals are not caused by external noise. It is also desirable to locate the source of the partial discharge activity and to quantify and assess the severity of the problem. We utilized several types of equipment to accomplish this.

The Partial Discharge Locator (PDL) utilizes a combination of sensors and signal processing to provide accurate location of the damaged insulation. The PDL is the most advanced portable instrument of its kind, incorporating two transient earth voltage (tev) sensors, two ultrasonic sensors, a high frequency current transformer sensor, a non-contact thermal temperature measurement sensor, an acoustic emission sensor, an ambient temperature sensor, an ambient humidity sensor and an ambient air pressure sensor. This combination of technologies provide for a very powerful instrument.

We also utilize 12-channel Partial Discharge Monitor (PDM) to determine PD location and severity. The PDM utilized 8 magnetic TEV sensors and 4 antennas to record PD activity over several days or weeks. This allows for accurate location and severity assessment. The PDM will also detect PD variations over time. After performing the Level II survey, a precise plan of action can be determined to correct the problem.

This switchgear insulation has suffered severe tracking damage and would soon fail completely. Our Level PD II service detected the intensity and location of this problem before catastrophic failure occurred.

The report page above represents the results of Level II cable testing that detected a splice problem about 300’ away. Detailed Level II testing is conducted while your equipment remains in service and utilizes a variety of advanced methods to provide insulation condition so that failures can be avoided.