25th annual Electrical Engineering Safety Seminar 2015

1. The Benefits of Partial Discharge
Monitoring
Ben Jones
Site Electrical Services Superintendent 5th November, 2015

2. Introduction
 Ben Jones – Site Electrical Services Superintendent
 OneSteel Newcastle – A division of Arrium Mining & Materials
 Commenced working career on the Newcastle site for BHP in
1997
 Have been responsible for the Newcastle High Voltage Network
since 2004

3. 2000 – New company Onesteel from the demerger of BHP - Steel
2005 – began exporting iron ore - Mining
2007 – acquired Smorgon Steel & Recycling business
2010 – purchase of Moly-Cop – Mining Consumables
2012 – changed name to ARRIUM Mining and Materials to reflect our diversity
into Mining

4.  Partial Discharge (PD) is a localised
dielectric breakdown of a small portion of
the electrical insulation system under
high voltage stress, which does not
completely bridge the space between two
conductors.
What is Partial Discharge (PD)?
 PD usually begins within voids, cracks, or
inclusions within a solid dielectric, in
bubbles within liquid dielectrics or with the
ionisation of air around a high voltage
conductor commonly referred to as
Corona.

5. Internal Discharge
PD spark occurs within the voids
due to the dielectric constant of
the void being lower than the
insulation. As the voltage across
the void exceeds the Corona
Inception Voltage PD occurs.

6. Surface Discharge
Corona Discharge
is an electrical
discharge brought
on by the
ionisation of air
surrounding a
High Voltage
conductor due to
the intensity of
the magnetic
field.

7. Accelerated HV Breakdown Test

8. What does PD do?
Besides creating light, audible noise and ozone gas it can also:
 Generate ultra violet radiation which will degrade fibres and polymers such as
polypropylene and polyethylene.
 Ionises the air around conductors
 Create nitric oxide and in the presence of moisture nitric acid which oxidises
surrounding exposed metals.
 Cause progressive deterioration of insulating materials, ultimately leading to
electrical breakdown.

9. Arrium Major HV Failure Data
2007>2010
• Average 3 failures per year
• Costing on average $5M per
failure

10. 11kV High Voltage Failure of YSF6
Yorkshire Switch Board

11. 22kV High Voltage Termination Box
Failure

12. 33kV High Voltage Sefton Termination Box
Failure

13.  Each of the above failures resulted in days of limited or no production
capacity. Costs quickly escalated in some cases to millions of dollars
when lost production and repair costs were calculated.
 Luckily none of the above events resulted in personal injury but we
must not forget the potential for such an occurrence to cause serious
harm or even death.
Impact

14. Locating Partial Discharge
The emissions generated by Partial Discharge
allows it to be to be located by the use of a
sensitive listening device such as the UltraTEV
Plus.
 This instrument is used to test for Transient Earth Voltages (TEV)
and Ultrasonic signals emanating from discharge occurring within
the High Voltage asset.
 PD can be detected reliably in HV systems >4.1kV
 This method of condition monitoring can be completed safely with
the equipment energised and without the need to remove any
covers exposing potential shock or arc fault hazards to technicians.

15. Partial Discharge
Severity
 TEV’s are induced voltage
spikes on the surfaces of the
surrounding metalwork of high
voltage assets. The resulting
readings are directly proportional
to the condition of the insulation.
 For Ultrasonic detection dB is
used to determine severity.

16. Successful PD Detections
• PD detected using contact
probe on the external
surface of the 33kV
termination box.
• Opening box found a large
amount of condensation
and formulation of white
powder on the termination
creepage extension sheds.

17. Successful PD Detections
• PD detected using
contact probe on the
external surface of the
33kV termination box.
• Opening box found
breakdown of the
termination kits where
insufficient air gap
between conductors
was maintained.

18. • PD detected using the
extension microphone in
and around an 11kV
circuit breaker.
• Discharge was occurring
between two covers
protecting the live
terminations underneath.
Successful PD Detections

19. • PD detected using the extension
microphone in and around an 11kV
circuit breaker.
• Discharge was occurring between
the connecting cluster and outer
insulating spouts.
Successful PD Detections

20. Successful PD Detections
PD detected using the
ultrasonic probe attached to
the outside of the 11kV
termination box enclosure

21. Successful PD Detections
PD detected using the ultrasonic
probe attached to the outside 11kV
termination box enclosure.

22. • PD detected using
contact probe on the
external surface of the
33kV termination box.
• Opening box found
breakdown of the
termination kits where
insufficient air gap
between conductors
was maintained.
Successful PD Detections

24. Thank
You