Examples For Checking Tev Activity Levels - Baur PD-SGS User Manual

P D-S G S
Verifying whether detected activity is noise or PD
Substations are very often electrically noisy environments and this noise can be picked up by
the PD-SGS. Noise levels often reach or exceed 15 dB, in some harsh industrial
environments levels can be as high as 30 or even 40 dB. A simple check can be carried out
to help identify whether the activity detected is coming from the switchgear or is noise from
surrounding plant.
1. Measure the highest level of activity on the switchgear panel.
2. Measure background noise in the substation by placing the PD-SGS sensor up against a
metallic object that is not electrically coupled to the switchgear under test. This will give a
background reference level.
3. If the activity level measured on the switchgear is more than 6 dB higher on the
switchgear than it is on the reference object then there is a high likelihood that the
activity is discharge coming from within the switchgear. Further investigative tests should
be carried out using more sophisticated PD test equipment such as the BAUR online PD
spot tester liona or the offline diagnostics system PD Portable.
10.1

Examples for checking TEV activity levels

Example 1 – PD-SGS placement on component switchgear
 Test for activity in all 3 positions.
Where the switchgear has exposed components such as the bus bar chamber, current
transformer or voltage transformer chamber, circuit breaker and cable box, then each part
should be tested for activity as shown in the figure above.
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