Extensive Presentation with 14 Case Studies from High Voltage Assets Preventative Maintenance by Non-intrusive testing using Partial Discharge detection and monitoring equipment. This Presentation contains: Author's Key Facts, Integrated Steelworks Plants brief overview of processes and Biggest Private HV Network in the UK Single Line Diagram - to highlight importance of HV Assets importance to the whole site uninterrupted operations, 14 case studies showing various High Voltage Switchgear and Transformers Partial Discharge issues detected, located and eliminated by prompt action.

1. EA Technology Partial Discharge Forum 26 03 2015
Partial Discharge monitoring of HV assets
- experience from Tata Steel site, Scunthorpe.
Highlighting defects with specific switchgear which led to Partial Discharge, and the methods
implemented to manage these assets.
Mikolaj Kukawski MIET
Customer Networks Manager
ESM Power

2. Content of presentation
• My background
• TATA Steel HV Distribution Network
• Integrated Steelworks Processes
• Partial Discharge Case Studies (14)
• Special thanks and questions

3. My background
Education:
• 2001-2006 - University of Lublin, Poland
- Master’s degree in Electrical Engineering – Power Systems
Work experience:
• 2006-2007 - Elektromontaz Lublin, Poland
- Design Engineer for MV Switchgear Manufacturer – 1 year
• 2007-2008 - Corus Power & Distribution (P&D), Scunthorpe, UK
- HV Electrician Team Member – 18 months

4. My background
Work experience:
• 2008-2014 - Corus / TATA Steel P&D, Scunthorpe, UK
- Distribution Engineer - 6 years
• 2014 Dec - currently - ESM Power, Scunthorpe, UK
- Customer Networks Manager

5. Integrated Steelworks HV Distribution Network

6. Integrated Steelworks 33kV Distribution Network Block Diagram

7. Integrated Steelworks 33kV Distribution Network Block Diagram

8. Integrated Steelworks Site Map showing 12 main plants

9. TATA STEEL Integrated Steelworks - Scunthorpe Site

10. Integrated Steelworks Process Block Diagram

11. Integrated Steelworks Process Block Diagram

12. Immingham
Bulk
Terminal

13. Immingham Bulk
Terminal
Unloading iron ore
from the ship

14. A train with coal wagons
unloads at Dawes Lane
Coal Handling Plant

15. A train with Iron Ore arrives at Scunthorpe Ore Blending Plant

16. Blending
the various
iron ores
and lime

17. Sinter
Plant
Coolers

18. Coal stocks
at the Coal
Handling
Plant

19. Pushing
a coke
oven

20. Blast Furnaces
also known as
The Four Queens:
– Mary, Bess,
Anne & Victoria

21. Queen Bess blast
furnace casting

22. Molten iron is
transported to
Steelmaking Plant
using torpedo wagons

23. Molten iron is
transported to
Steelmaking Plant
using torpedo wagons

24. Charging molten iron
into BOS converter

25. Charging scrap into
BOS converter

26. Ladle Arc Furnace -
secondary steelmaking

27. Twin strand bloom
caster tundish

28. 8 strand Billet Caster

29. A pack of billets
on the BBM
cooling bank

30. Bloom Caster 4

31. Slab Caster

32. A slab leaves the
Plate Mill reheater
furnace

33. Rolling plate at
Heavy Plate Mill

34. Plate cooling bank
at Heavy Plate Mill

35. Scunthorpe Rod Mill

36. Laying head at
Scunthorpe Rod Mill

37. Scunthorpe
Rail and
Section Mill
Area 3
also known as
Rail Service
Centre

38. Partial Discharge Case Studies
1 - Central Power Station 33 kV Substation
2 - Central Power Station 3.3 kV
3 - Blast Furnaces 11 kV
4 - Bloom Mill 11 kV
5 - BOS Waste Gas Recovery 11 kV
6 - Ore Blending Plant Main 11 kV
7 - Blast Furnaces No. 2 6.6 kV
8 - BOS Waste Gas Recovery 11 kV Busbar Outage
9 - Heavy Section Mill to Scunthorpe Rod Mill 33 kV Interconnector Reactor Terminations
10 - Broughton to Seraphim 33 kV Interconnector
11 - Seraphim 33 kV Reyrolle L42T VT
12 - CONCAST Water Treatment Plant 11 kV GEC BVP 17 Busbar
13 - Heavy Plate Mill Roughing Mill Transformer Cast Resin Transformer 33 kV
14 - Bloom Caster 11 kV

39. Partial Discharge Monitor

40. Integrated Steelworks HV Distribution Network

41. Integrated Steelworks HV Distribution Network

42. Case Study 1 - Central Power Station 33 kV Substation
Affected Asset details:
1. Equipment Circuit VT
2. Make Reyrolle
3. Model L800T
4. Operating voltage 33kV
5. Number of panels 13 (Section 3 only 2 circuits)
6. Age 40 years

45. Reyrolle L800T 33kV Switchgear
(single busbar system) cross
section drawing

46. Reyrolle L800T 33kV Switchgear
(single busbar system) cross
section drawing

47. CPS 33kV
Substation
Reyrolle
L800T
33kV
Switchgear

48. CPS 33kV Substation Reyrolle
L800T 33kV Switchgear –
Section 3

49. Case Study 1 - Central Power Station 33 kV Substation
Investigation details:
1. Partial discharge initial detection method - CPS power controller detected red TEV
using hand held UltraTEV detector during daily substation checks – informed duty
engineer
2. Follow up investigation method – Distribution Engineer and Team Leader joint
investigation using UltraTEV +. Switchboard tested Left to Right, Front to Rear and
Top to Bottom. Conclusion: On the circuit: 33/11kV 12/24MVA Transformer No.3 (T3)
the higher the measurement was taken the higher the TEV reading was (up to 50dB).
Decided to test Circuit VT located on the top of the switchgear. Confirmed that the
TEV reading was even higher (60dB).
3. Action taken - decided to isolate T3 circuit

50. T3 circuit VT
fixed portion L2
(yellow) phase
spout

51. T3 circuit VT
fixed portion L2
(yellow) phase
spout

52. T3 circuit VT
moving portion
L1 and L2
(red and yellow)
phases spouts

53. T3 circuit VT
moving portion
L2 and L3
(yellow and blue)
phases spouts

54. T3 circuit VT
moving portion
L2 (yellow) phase
spout

55. T3 circuit VT
moving portion
L2 (yellow) phase
spout

56. T3 circuit VT
moving portion
L2 (yellow)
phase spout

57. Case Study 1 - Central Power Station 33 kV Substation
Outage requirement to enable investigation and repair
1. Equipment Section 3 bus bars at CPS 33kV, CPS 33/11kV 12/24MVA
Transformer No.3 circuit, CPS to HPM 33kV Interconnector
2. Timescale 2 hours on the T3 circuit, 15 minutes HPM stopped rolling to
enable T3 33kV OCB re-closure without its circuit VT.

58. Case Study 1 - Central Power Station 33 kV Substation
Actions taken to rectify the fault
1. Resources Investigation TATA, Siemens for VT repair
2. Discharge elimination Circuit VT withdrawn,
3. Repair method Cracked VT bushing to be replaced
4. Estimated cost of repair circa £ 10k
Has PD activity stopped? YES – TEV level went back to green
Possible cause of partial discharge VT Bushing damaged during installation
Loss estimation in worst case scenario:
Circa £ 200k for 2 33kV switchgear panels replacement and potentially HPM production loss and
internal generation limited due to 1 of 3 33/11kV transformers outage.

59. Case Study 2 - Central Power Station 3.3 kV
Affected Asset details:
1. Equipment Single core 3.3kV unarmoured cable
2. Make GEC
3. Model BTVP17 and HMC
4. Operating voltage 3.3kV
5. Number of panels 15
6. Age 40 years

62. GEC BTVP17 3.3kV Switchgear
(double busbar system) cross section
drawing

63. GEC BTVP17 3.3kV Switchgear
(double busbar system) cross section
drawing

64. CPS 3.3kV
Substation GEC
BTVP17 3.3kV
Switchgear
(rear view)

65. Case Study 2 - Central Power Station 3.3 kV
Investigation details:
1. Partial discharge initial detection method - CPS power controller detected red TEV on
Incomer from 5MVA No.1 Transformer using hand held UltraTEV detector during daily
substation checks – informed duty engineer
2. Follow up investigation method – Distribution Engineer investigated the switchboard using
UltraTEV +. Switchboard tested Left to Right, Front to Rear and Top to Bottom. Conclusion:
On the Incomer No.1 circuit the lower the measurement was taken the higher the TEV
reading was (up to 44dB). Decided to Inspect cable box. No evidence of Partial Discharge
found. Tested switchboard Using Partial Discharge Monitor. Tested switchboard again using
UltraTEV + and realised that that the TEV reading was even higher on the bottom of cable
box support channel – near the floor (60dB). Question asked: What is underneath the
substation? It turned out to be mezzanine floor with cables installed on metal trays system.
Found one core stuck against metal support construction channel with signs of partial
discharge.

66. CPS 3.3kV
Substation GEC
BTVP17 3.3kV
Switchgear
(Incomer from
5MVA No.1
Transformer -
cable box
inspection)

67. Case Study 2 - Central Power Station 3.3 kV
Investigation details:
3. Action taken – Circuit isolated, tested IR of the cable – 4 Mega Ohms - asked
experienced jointer for advice – suggested using triple layer of HV heat shrink
tape around damaged area of the cable. Cable repaired. Circuit reenergised. TEV
levels dropped down to 30dB at the repair point and down to 27 dB above the
repair point, investigated further the cable route – found cables tightened with
twisted steel wire armouring to form two trefoil formations (instead of using
proper trefoil cleats). Steel wire armouring is cutting through PVC insulation of
unarmoured cables on the majority of the cable routes. Decided to replace all
3.3kV cables for both No.1 and No.2 5MVA Transformers Incomers.

68. CPS 3.3kV
Substation
mezzanine floor
(Incomer from
5MVA No.1
Transformer -
Single core
unarmoured
cables)

69. CPS 3.3kV
Substation
mezzanine floor
(Incomer from
5MVA No.1
Transformer -
Single core
unarmoured
cables)

70. CPS 3.3kV
Substation
mezzanine floor
(Incomer from
5MVA No.1
Transformer -
Single core
unarmoured
cables)

71. CPS 3.3kV
Substation
mezzanine floor
(Incomer from
5MVA No.1
Transformer -
Single core
unarmoured cable
repaired)

72. CPS 3.3kV Substation mezzanine floor
(Incomer from 5MVA No.1 Transformer -
Single core unarmoured cable repaired –
TEV level dropped to 30dB)

73. CPS 3.3kV Substation mezzanine floor
(Incomer from 5MVA No.1 Transformer -
Single core unarmoured cable repaired –
TEV level dropped to 27dB above repair
point)

74. CPS 3.3kV Substation mezzanine floor
(Incomer from 5MVA No.1 Transformer
- Single core unarmoured cable
repaired – TEV level dropped to 30dB)

75. Single core
unarmoured cables
tightened with
twisted steel wire
armourings

76. Original cable schedule dated 1974 showing the type and route of the cables

77. Case Study 2 - Central Power Station 3.3 kV
Outage requirement to enable investigation and repair
1. Equipment No.1 5MVA 11/3.3kV Transformer at CPS 3.3kV,
2. Timescale 6 hours for the cable box inspection, 4 hours for cable repair

78. Case Study 2 - Central Power Station 3.3 kV
Actions taken to rectify the fault
1. Resources Investigation TATA, SPEC for cable repair
2. Discharge elimination Cable replacement,
3. Repair method New cables installation with correct trefoil cleats
4. Estimated cost of repair circa £ 20k
Has PD activity stopped? NO – however TEV level reduced to amber level on the
switchboard
Possible cause of partial discharge Cable damaged due to incorrect installation method
Loss estimation in worst case scenario:
Potentially loss of internal generation since 3.3kV switchboard feeds auxiliary equipment essential for
steam raising processes. Possible knock on effect on process steam system for the whole site.

79. Case Study 3 - Blast Furnaces 11 kV
Affected Asset details:
1. Equipment Vacuum Circuit Breakers (VCB)
2. Make GEC
3. Model VMX
4. Operating voltage 11kV
5. Number of panels 19 (5 VCB’s affected)
6. Age 26 years

82. GEC VMX 11kV Switchgear
(single busbar system)
cross section drawing

83. GEC VMX 11kV Switchgear
(single busbar system)
cross section drawing

84. GEC VMX 11kV Switchgear
(single busbar system)
cross section drawing

85. GEC VMX 11kV
Vacuum Circuit Breaker (VCB)
cross section drawing

86. GEC VMX 11kV
Vacuum Circuit Breaker (VCB)
cross section drawing

87. Blast Furnaces
11 kV Substation
GEC VMX 11kV
Switchgear
(single busbar
system)

88. Case Study 3 - Blast Furnaces 11 kV
Investigation details:
1. Partial discharge initial detection method – TATA Steel Power and Distribution
craftsmen detected red TEV using hand held UltraTEV detector during weekly
substation checks – informed duty engineer
2. Follow up investigation method – Distribution Engineer investigated switchboard
using UltraTEV +. Switchboard tested Left to Right, Front to Rear and Top to Bottom.
Conclusion: On the circuit: 33/11kV 12/24MVA Transformer Incomer No.1 the
highest TEV level measured was at the front of VCB (up to 40dB). In conjunction with
BF Engineers decided to take the suspected VCB out of service.
3. Action taken – Incomer No.1 VCB isolated and retested the switchboard with
UltraTEV + - TEV level back to green

89. Incomer No.1 GEC VMX
11kV VCB L2 (yellow phase)
front isolating contact
front – busbar,
rear - circuit

90. Incomer No.1 GEC VMX 11kV VCB L2 (yellow phase) front isolating contact

91. New VMX unit for Incomer No.1 - showing L2 (yellow phase) front isolating contact

92. Case Study 3 - Blast Furnaces 11 kV
Outage requirement to enable investigation and repair
1. Equipment Incomer No.1 from 33/11kV 12/24MVA Transformer circuit
2. Timescale 2 hours to replace VCB with the new or refurbished unit from
Schneider

93. Case Study 3 - Blast Furnaces 11 kV
Actions taken to rectify the fault
1. Resources Investigation TATA, new or refurbished VMX unit – Schneider
2. Discharge elimination VMX VCB replacement,
3. Repair method VMX body moulding replaced and ball bearing added to the
drive shaft
Estimated cost of repair VMX refurbishment circa £ 5k, new VMX unit circa £ 14k
Has PD activity stopped? Yes
Possible cause of partial discharge – partial discharge possibly due to continuous charging and
discharging of unearthed metal drive shaft which goes through the middle of VMX body
moulding.
Loss estimation in worst case scenario:
Potentially loss of production on crucial iron making plant since 11kV switchboard feeds
charging side of all four blast furnaces essential for iron making processes. Possible site-wide
knock on effect including steelmaking and mills.

94. Other VMX circuit breakers affected by partial discharge – bus section

95. Other VMX circuit breakers affected by partial discharge – bus section

96. Other VMX
circuit breakers
affected by
partial discharge
– Queen Anne
2MVA No.2
Transformer
VCB

97. Other VMX
circuit breakers
affected by
partial discharge
– Queen Anne
2MVA No.2
Transformer
VCB

98. Other VMX circuit
breakers affected by
partial discharge –
Substation Auxiliary
2MVA Transformer
No.2 VCB

99. Other VMX circuit breakers affected by partial discharge – incomer No.2

100. Other VMX circuit breakers
affected by partial discharge
– incomer No.2

101. Case Study 4 - Bloom Mill 11 kV
Affected Asset details:
1. Equipment Busbar Voltage Transformer (VT)
2. Make GEC
3. Model BVP17
4. Operating voltage 11kV
5. Number of panels 16 (Section 2 Busbar VT affected)
6. Age 45 years

104. Bloom Mill 11kV
Substation GEC BVP17
11kV Switchgear
(single busbar system)
- showing Section 2 of
the switchboard
isolated and Section 2
busbars earthed

105. GEC BVP17
VT cross
section
drawing
– showing
indentation
in the rail to
prevent VT
movement
whilst in
service
position

106. GEC BVP17
VT cross
section
drawing
– showing
indentation
in the rail to
prevent VT
movement
whilst in
service
position

107. Bloom Mill 11kV
Section 2 Busbar VT

108. Bloom Mill 11kV
Section 2 Busbar VT

109. Bloom Mill 11kV
Section 2 Busbar VT

110. Bloom Mill 11kV
Section 2 Busbar VT

111. Bloom Mill 11kV
Section 2 Busbar VT

112. Case Study 4 - Bloom Mill 11 kV
Investigation details:
1. Partial discharge initial detection method – BBM engineer informed duty engineer
about audible discharge in Section 2 Switchroom of Bloom Mill 11kV Substation.
2. Follow up investigation method – Distribution Engineer arrived on site and located
the discharge near Section 2 Busbar VT.
3. Action taken - decided to isolate suspected Section 2 Busbar VT

113. Case Study 5 - BOS Waste Gas Recovery 11 kV
Affected Asset details:
1. Equipment Vacuum Circuit Breakers (VCB)
2. Make GEC
3. Model VMX
4. Operating voltage 11kV
5. Number of panels 9 (5 VCB’s affected)
6. Age 26 years

114. BOS Waste Gas Recovery 11 kV
Substation - bus section GEC
VMX VCB L2 (yellow phase)
front isolating contact

115. Bus section GEC VMX 11kV VCB L2 (yellow phase) front isolating contact

116. Other VMX
circuit breakers
affected by
partial discharge
– Incomer No.2

117. Other VMX
circuit breakers
affected by
partial discharge
– Incomer No.2

118. Other VMX
circuit breakers
affected by
partial discharge
– Incomer No.2

119. Other VMX
circuit breakers
affected by
partial discharge
– Incomer No.2

120. Other VMX
circuit breakers
affected by
partial discharge
– Incomer No.2

121. Other VMX
circuit breakers
affected by
partial discharge
– Incomer No.2

122. Case Study 6 - Ore Blending Plant Main 11 kV
Affected Asset details:
1. Equipment Current Transformers (CT’s)
2. Make GEC
3. Model BVP17
4. Operating voltage 11kV
5. Number of panels 6 (1 OCB panel circuit chamber affected)
6. Age 27 years

123. GEC BVP17 11kV Switchgear (single busbar system) cross section drawing

124. Ore Blending Plant
Main 11 kV
Substation

125. Ore Blending Plant
Main 11 kV
Substation
Incomer No.1 CT’s
affected by partial
discharge

126. Ore Blending Plant Main 11 kV Substation Incomer No.1 CT’s
affected by partial discharge

127. Case Study 6 - Ore Blending Plant Main 11 kV
Actions taken to rectify the fault
1. Resources Investigation TATA, CT’s & bushings repairs – Schneider
2. Discharge elimination Incomer No.1 circuit isolated
3. Repair method CT’s removed, repaired and fitted by OEM
Estimated cost of repair CT’s repairs: labour circa £ 8k, materials circa £ 2.5k
Has PD activity stopped? Yes
Possible cause of partial discharge – partial discharge possibly due to broken CT’s earth
clamps. It is likely that high humidity within substation was a contributing factor.
Loss estimation in worst case scenario:
Potential loss of production on Ore Blending Plant – crucial for Sinter making process.
Possible site-wide knock on effect including ironmaking, steelmaking and mills.

128. Case Study 7 - Blast Furnaces No. 2 6.6 kV
Affected Asset details:
1. Equipment Cable terminations
2. Make Brush
3. Model VMVD
4. Operating voltage 6.6kV
5. Number of panels 23 (2 VCB panels cable terminations affected)
6. Age 25 years

129. Brush VMVD 6.6kV
(double busbar system)
cross section drawing

130. Brush VMVD 6.6kV
(double busbar system)
cross section drawing

131. Brush VMVD 6.6kV substandard cable terminations

132. Brush VMVD 6.6kV -substandard cable terminations

133. Brush VMVD 6.6kV
new cable terminations

134. Case Study 7 - Blast Furnaces No. 2 6.6 kV
Actions taken to rectify the fault
1. Resources Investigation TATA, cable terminations repairs – SPEC
2. Discharge elimination 2 circuits isolated
3. Repair method cable terminations removed, cables cut, jointed new
pieces of cable in the basement and terminated with
Raychem heat shrink termination kits
Estimated cost of repair new cables, joints and terminations circa £ 7k
Has PD activity stopped? Yes
Possible cause of partial discharge – partial discharge possibly due to substandard cable
terminations.
Loss estimation in worst case scenario:
Potential loss of production on ironmaking. Possible site-wide knock on effect including
steelmaking and mills.

135. Air Cooled Transformer Partial Discharge in the substation next door

136. Air Cooled Transformer Partial Discharge in the substation next door

137. Air Cooled Transformer Partial Discharge in the substation next door

138. Air Cooled Transformer Partial Discharge in the substation next door

139. Air Cooled Transformer Partial Discharge in the substation next door

140. Air Cooled Transformer Partial Discharge in the substation next door

141. Case Study 8 - BOS Waste Gas Recovery 11 kV Busbar Outage
Affected Asset details:
1. Equipment Air insulated busbars
2. Make GEC
3. Model VMX
4. Operating voltage 11kV
5. Number of panels 9
6. Age 26 years

142. GEC VMX 11kV Switchgear
(single busbar system)
cross section drawing

143. GEC VMX 11kV
Switchgear
(single busbar system)
2 Section switchboard
View from the top
- showing busbars
arrangement
Section 1 Section 2

144. GEC VMX 11kV
Switchgear
(single busbar system)
2 Section switchboard
View from the top
- showing busbars
arrangement
Section 1 Section 2

145. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

146. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

147. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

148. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

149. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

150. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

151. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

152. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

153. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

154. BOS Waste Gas Recovery 11 kV Switchboard – Section 2 busbar inspection

155. Case Study 9 - Heavy Section Mill to Scunthorpe Rod Mill 33 kV
Interconnector Reactor Terminations
Affected Asset details:
1. Equipment 33kV cable terminations inside air cable box of reactor
2. Make Yorkshire Electric Transformer Company Ltd.
3. Model 21 MVA to British Standard Specification 171/1956
4. Operating voltage 33kV
5. Number of panels N/A
6. Age 41 years (refurbished by SPEC in 2006)

158. Blast Furnace to Scunthorpe Rod Mill 33 kV Interconnector Reactor

159. Blast Furnace to Scunthorpe Rod Mill 33 kV Interconnector Reactor

160. Heavy Section Mill to Scunthorpe Rod Mill 33 kV Interconnector Reactor Terminations

161. Heavy Section Mill to Scunthorpe Rod Mill
33 kV Interconnector Reactor Terminations

162. Heavy Section Mill to
Scunthorpe Rod Mill
33 kV Interconnector
Reactor Terminations

163. Heavy Section Mill to Scunthorpe
Rod Mill 33 kV Interconnector
Reactor Terminations

164. Heavy Section Mill to
Scunthorpe Rod Mill
33 kV Interconnector
Reactor Terminations

165. Heavy Section Mill to
Scunthorpe Rod Mill 33 kV
Interconnector Reactor
Terminations

166. Case Study 9 - Heavy Section Mill to Scunthorpe Rod Mill 33 kV
Interconnector Reactor Terminations
Actions taken to rectify the fault
1. Resources Investigation TATA, cable terminations repairs – SPEC
2. Discharge elimination 33kV Interconnector circuit isolated
3. Repair method cables re-terminated
Estimated cost of repair new terminations circa £ 7k
Has PD activity stopped? Yes
Possible cause of partial discharge – partial discharge possibly due to substandard cable
terminations (i.e. clearances between termination sheds not sufficient)
Loss estimation in worst case scenario:
Security of site power supplies compromised – SRM down to 3 out of 4 Interconnectors.

167. Blast Furnace to Rod Mill 33 kV Interconnector Reactor Cable Terminations Failure

168. Blast Furnace to Rod Mill 33 kV Interconnector Reactor Cable Terminations Failure

169. Blast Furnace to Rod Mill 33 kV Interconnector Reactor Cable Terminations Partial Discharge

170. Blast Furnace to Rod Mill 33 kV Interconnector Reactor Cable Terminations Partial Discharge

171. Case Study 10 - Broughton to Seraphim 33 kV Interconnector VT and
Case Study 11 - Seraphim to BF Interconnector VT
Affected Asset details:
1. Equipment Circuit VT
2. Make Reyrolle
3. Model L42T
4. Operating voltage 33kV
5. Number of panels 23
6. Age circa 40 years

172. Reyrolle L42T 33kV Switchgear
(single busbar system) cross
section drawing

173. Broughton to Seraphim 33 kV Interconnector

174. Reyrolle L42T 33kV Switchgear
Circuit VT removed from traversing carriage
onto mono rail in readiness to be removed from
site and tested at Siemens Hepburn Works

175. Reyrolle L42T
33kV Switchgear
Cable box fitted
with UltraTEV
Alarm Hub and
ultrasonic
microphone

176. Siemens 8DA10
33kV standalone
switchgear panel
fitted with
UltraTEV Alarm
Hub and
ultrasonic
microphone

177. UltraTEV Alarm System
with SCADA interface
(remote I/O connection)
Installed at Grid Supply
Point Broughton 33kV
Substation – 1 system
per Section

178. Seraphim 33 kV Substation

179. Reyrolle L42T
33kV Switchgear
Cable box fitted
with UltraTEV
Alarm Hub and
ultrasonic
microphone

180. Case Study 12 - CONCAST Water Treatment Plant 11 kV Busbars
Affected Asset details:
1. Equipment Busbars
2. Make GEC
3. Model BVP17
4. Operating voltage 11kV
5. Number of panels 11
6. Age circa 40 years

181. Concast Plant
11kV Substation
role within
Steelmaking
11kV distribution
system

182. GEC BVP17 11kV
Switchgear
(single busbar system)
3 Section switchboard
View from the top
- showing busbars
arrangement
3 circuits per Section
Section 1 Section 2

183. GEC BVP17 11kV
Switchgear
(single busbar system)
3 Section switchboard
View from the top
- showing busbars
arrangement
3 circuits per Section
Section 1 Section 2

184. Concast Plant 11kV Switchboard
– Section 2 busbars at the back
of Bus Section 1 – 2 OCB panel

185. Concast Plant 11kV Switchboard –
damage to the L2 (yellow phase)
busbar sleeve

186. Concast Plant 11kV Switchboard –
damage to bakelite busbar
spacing fittings with rubber
inserts

187. Concast Plant 11kV
Switchboard
– busbars removed
and taken to
Schneider factory
for repairs and
resleeving

188. Case Study 12 - CONCAST Water Treatment Plant 11 kV Busbars
Actions taken to rectify the fault
1. Resources Investigation & busbars removal/installation – TATA,
busbars repairs and new busbar spacing materials –
Schneider
2. Discharge elimination 11kV busbars Sections 1&2, 2nd outage sections 2&3
isolated.
3. Repair method busbars re-sleeved and new busbar spacing fitted
Estimated cost of repair total cost of all repairs circa £ 25k
Has PD activity stopped? Yes
Possible cause of partial discharge – PD due to poor substation heating in winter time
which led to high humidity levels (90%) and water condensation on substation ceiling.
Loss estimation in worst case scenario:
Slab caster loss of production with possible knock on effect on Plate Mill.

189. Case Study 13 - Heavy Plate Mill Roughing Mill Transformer Cast
Resin Transformer 33 kV
Affected Asset details:
1. Equipment Cast Resin Transformer
2. Make ABB
3. Model 4.1MVA
4. Operating voltage 33/1kV
5. Number of panels N/A
6. Age 7 years

191. Heavy Plate Mill
Roughing Mill
Main Drive Cast
Resin Transformer
33/1 kV 4.1MVA

192. Heavy Plate Mill
Roughing Mill
Main Drive Cast
Resin Transformer
33/1 kV 4.1MVA –
loose eye bolt nut

193. Heavy Plate Mill
Roughing Mill
Main Drive Cast
Resin Transformer
33/1 kV 4.1MVA –
substandard LV
cable connection

194. Heavy Plate Mill Roughing Mill Main Drive
Cast Resin Transformer 33/1 kV 4.1MVA –
PD found on 33kV CT’s connections

195. Case Study 14 - Bloom Caster 11 kV
Affected Asset details:
1. Equipment Vacuum Circuit Breakers (VCB)
2. Make GEC
3. Model VMX
4. Operating voltage 11kV
5. Number of panels 11 (2 VCB’s affected)
6. Age 19 years

196. GEC VMX 11kV Switchgear
(single busbar system)
cross section drawing

197. GEC VMX 11kV Switchgear
(single busbar system)
cross section drawing

198. GEC VMX 11kV VCB – incomer No.1 L2
(yellow phase) front isolating contact

199. GEC VMX 11kV VCB
– incomer No.1
L2 (yellow phase)
front isolating
contact

200. GEC VMX 11kV VCB
– incomer No.1
L2 (yellow phase)
front isolating
contact

201. GEC VMX 11kV VCB – incomer No.1
L2 (yellow phase) front isolating contact

202. Special thanks

203. This presentation was made thanks to 8 years of experience in
maintaining on one of the largest private HV network – TATA Steel in
Scunthorpe, North Lincolnshire, UK
Presentation prepared with permission of:
John Simpson – TATA Steel Scunthorpe Electrical Infrastructure, SRCS
and DSEAR Engineer, HV Engineer in Charge for Scunthorpe &
Immingham Works
Special thanks to Paul Wilson for Scunthorpe Steelworks photographs

204. Special thanks
to my wife Gosia!

205. Any questions?

206. Thank you.