1. PD Detection on Metal Enclosed Switchgear Panels
PARTIAL DISCHARGE DETECTION ON METAL ENCLOSED SWITCHGEAR PANELS BY LENNY GOVENDER AND KAMENDREN GOVENDER
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

2. PRESENTATION OVERVIEW
Introduction
Partial Discharge
Acoustic Emission Tests
Operation
Basic Examples
Case Studies
Conclusion
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

3. PD Detection on Metal Enclosed Switchgear Panels
INTRODUCTION
TE is responsible for maintenance of ± metal enclosed switchgear panels operating at 11 kV
Reliability of aging switchgear panels is of paramount importance to the stability and performance of the network
TE has embarked on a condition assessment program through the introduction of advanced diagnostic testing
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

4. PD Detection on Metal Enclosed Switchgear Panels
INTRODUCTION (cont.)
Use of acoustic techniques seems to be an excellent starting point for the detection of partial discharges in 11 kV switchgear panels
This method had proven itself invaluable in the detection of Partial Discharge within GIS
This non-invasive method has the ability to detect, locate and evaluate defects within switchgear panels
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

5. PD Detection on Metal Enclosed Switchgear Panels
PARTIAL DISCHARGE
Definition
..is an electrical discharge that only partially bridges the insulation between conductors and which may or may not occur adjacent to a conductor…
Mediums ???
Solid, Liquid & Gas
Why Test ???
Degradation of insulation material
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

6. ACOUSTIC EMISSION TESTS
Acoustic transducers detect and capture energy
Data Interpretation
Acoustic energy radiates from discharge source
Figure 1: Sound Energy from a Discharge Source
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

7. ACOUSTIC EMISSION TESTS (cont.)
Practical Testing
In practice it tends only to be used for the detection of discharges in gas equipment and surface tracking or corona
Surface Tracking
Tracking is the formation of a permanent conducting path across an insulator surface
Usually the conduction path results from degradation of the insulation
Corona
Detection is usually performed at frequencies between 30kHz and 90kHz
Absolute levels are likely to vary considerably with atmospheric conditions
Concentration on variation in recorded levels between similar pieces of equipment should be done
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

8. PD Detection on Metal Enclosed Switchgear Panels
OPERATION
Acoustic Emission Testing
AE proved successful as diagnostic tool for GIS
Experimented on metal enclosed switchgear
The Instrument
Ultrasonic sensor – monitors signals
μC performs data operation
Results displayed on LCD screen
Record the background noise
Screen the panel by moving the sensor
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

9. OPERATION(cont.) RMS Value during one power cycle
Periodic Peak during one power cycle
Degree of modulation with the power cycle
Degree of modulation with twice the power cycle
Figure 2: Continuous Mode with Background noise
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

10. PD Detection on Metal Enclosed Switchgear Panels
BASIC EXAMPLES
Figure 3 : Example1
Figure 4: Example 2
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

11. CASE STUDY 1 Continuous Mode
RMS bar and periodic peak value have increased
PD is present
Freq 1 and Freq 2 content
PD on
positive and negative cycles
Figure 5: PD detection in Continuous Mode
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

12. CASE STUDY 1(cont.) Phase Measuring Mode:
Correlation between the acoustic signal and power frequency
PD is present in both cycles
Figure 6: The Phase Measuring Mode
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PD Detection on Metal Enclosed Switchgear Panels

13. CASE STUDY 1(cont.) FINDINGS ??? Surface Discharge on the
Current Transformer
Figure 7: Surface Tracking on CT
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PD Detection on Metal Enclosed Switchgear Panels

14. CASE STUDY 2 Continuous Mode Phase Mode
RMS and Periodic Peak increased
PD in correlation to 100 Hz
Figure 8: Continuous measuring mode
PD is present
Phase Mode
Correlation between acoustic signal and the power frequency
Figure 9: The Phase Measuring Mode
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PD Detection on Metal Enclosed Switchgear Panels

15. CASE STUDY 2 FINDINGS??? PD ON THE CRUTCH
Figure 10: Inspection on Cable Terminations
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PD Detection on Metal Enclosed Switchgear Panels

16. PD Detection on Metal Enclosed Switchgear Panels
CONCLUSION
Acoustic Method has proven to be a reliable tool for condition assessment in GIS
Successful in detecting PD in metal enclosed switchgear
However, the drawbacks of this testing technique are:
Results can be influence by severe background noise; and
Only surface discharge can be detected
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels

17. PD Detection on Metal Enclosed Switchgear Panels
THANK YOU !!!
19/09/2018
PD Detection on Metal Enclosed Switchgear Panels