temperatures of connectors inside mv joints€¦ · presented to subcommittee b, spring 2015 ieee...

Temperatures of Connectors Inside MV Joints

Barry Fairley Thomas J. Parker Nigel Hampton

© GTRC

Presented to Subcommittee B, Spring 2015 IEEE PES ICC – April 13, 2015

Temperatures of Connectors Inside MV Joints Presented to Subcommittee B, Spring 2015 IEEE PES ICC – April 13, 2015

Notice

a. The material contained herein is, to our knowledge, accurate and reliable at the date of publication.

b. It is provided for the overall benefit of the electric energy delivery industry.

c. It shall not be construed as an endorsement of any project, process or provider by the Georgia Tech Research Corporation (GTRC), the Georgia Institute of Technology (GIT) or NEETRAC.

d. Neither GTRC nor GIT nor NEETRAC shall be responsible for any injury to or death of persons or damage to or destruction of property or for any other loss, damage or injury of any kind whatsoever resulting from the use of the project results and/or data.

e. GTRC, GIT and NEETRAC disclaim any and all warranties, both express and implied, with respect to analysis or research or results contained in this material.

f. It is the user's responsibility to conduct the necessary assessments in order to satisfy themselves as to the suitability of the products or recommendations provided in this material.

g. Title to the information herein shall reside with GTRC.

Background / Purpose

• The presentation at the Fall 2014 Sub B Meeting looked at the likelihood of ANSI compliant connectors in MV joints exceeding 130 °C.


Background (from previous work)

ANSI C119.4 CCST

Connector in 15 kV Joint

Temperatures of Connectors Inside MV Joints Presented to Subcommittee B, Spring 2015 IEEE PES ICC – April 13, 2015 4

Connector Temperatures by Conductor Temperature

(from previous work)

1201101009080

99

90

8070605040

30

20

10

5

3

2

1

Conductor Temperature When Connector Exceeds 130 °C

Perc

ent

5.2

9030.2

8.1

105

80.0

54.5

120

1/0 AWG750 kcmil

Conductor_Size

5 Temperatures of Connectors Inside MV Joints


Background / Purpose • Samples were removed from the MV joint portion of that test

program when the connector temperature reached 130 °C.

• SO HOW HOT WOULD THEY HAVE GOT?

• The work reported here used the same samples to measure connector temperatures reached when the limit was removed.

• The test procedures used in this project are patterned after, but not identical to, those in IEEE Standard 404.

• RECALL: Work is NOT an evaluation of connectors, joints or dies.


MV Joint Test Samples • 48 Connectors for 1/0 AWG conductors – Al, Strand,

TRXLPE, Jkt, 25 kV – Two connector types (Two different size compression

connectors) – Two joint types (Heat-shrink and Cold-shrink) – Four die types with different sizes and different crimps/side

• 54 Connectors for 750 kcmil conductors – Al, Strandfilled, EPR, Jkt, 25 kV – Four connector types (Two different size compression

connectors & two different size shear-bolt connectors) – Two joint types (Heat-shrink and Cold-shrink) – Two die types with similar sizes and same crimps / side – 10 of the 54 samples were not tested because they passed the

testing in the previous project Temperatures of Connectors Inside MV Joints


1/0 AWG IEEE 404 Style Joint Test



Test Program 1. Test existing samples that did not

complete 100 cycles at conductor temp of 120 °C – no new samples

2. 1/0 AWG & 750 kcmil samples 3. Monitored heat runs for ignition,

and any burnt out joints were removed

4. Temperature Cycling (8 hours per cycle) to establish moderate term stability

5. Dissection of joints after testing

5 Cycles @ 90 °C

5 Cycles @ 105 °C

10 Cycles @ 120 °C


750 kcmil Test Results


Example Typical Connector Results

First run with

conductor temperature

at 90 °C

Last run with

conductor temperature at 105 °C

First run with


Last run with


at 90 °C

First run with


at 120°C

Last run with



Typical Worst Case

Example Worst Connector Results

First run with


at 90 °C

Last run with conductor

temperature at 105 °C

First run with conductor

temperature at 105 °C

Last run with


at 90 °C

First run with conductor

temperature at 120°C

Last run before being

removed


Connector Temperature - 750 kcmil

220

180

140

130

120

110

1009080

99

90

8070605040

30

20

10

5

3

2

1

Final Temperature (C)

Perc

ent

5010

4

122

141

90105120

(C)TempCycle



Typical 750 kcmil Dissections

Sample 19 – Max. Temp. 135 °C Sample 35 – Max. Temp. 139 °C



1/0 AWG Test Results


Overheating of 1/0 Samples during Test


1/0 AWG Connectors Removed (exceeded 380 °C)

• Thermocouples used ceased to operate near 400 °C • At 90 °C conductor temperature, 5 out of 48 were

censored after test due to temperatures > 380 °C. • At 105 °C conductor temperature 15 out of 48 were

censored after test due to temperatures > 380 °C. • At 120 °C conductor temperature 34 out of 48 were

censored after test due to temperatures > 380 °C.


Connector Temperature - 1/0 AWG

400

300

200

150

140

130

120

110

1009080

99

90

8070605040

30

20

10

5

3

2

1

Max Temp (C)

Perc

ent

407090

105120

Temp CCycle


Typical 1/0 AWG Dissections

Sample 18 – Max. Temp. 390 °C Sample 44 – Max. Temp. 356 °C



Effect of Factors – 750 kcmil


Joint Type Conductor Temp

90 °C 105 °C 120 °C

Cold-shrink 105 124 140

Heat-shrink 101 118 132

Effect Significance

Joint Type Small Significant

Median Final Temps (°C) with Different Joint Types - 750 kcmil


Effect Significance

Connector Type Small Insignificant

Connector Conductor Temp

90 °C 105 °C 120 °C

Compression A (Medium) 105 125 141

Compression B (Medium) 102 120 136

Shear-bolt (Big) 98 115 122

Shear-bolt (Medium) 105 124 140

Median Final Temps (°C) with Different Connectors - 750 kcmil


Effect of Factors – 1/0


Joint Type Conductor Temp

90 °C 105 °C 120 °C

Cold-shrink >143 >208 >400

Heat-shrink 116 >150 >280

Effect Significance

Joint Type Large Moderately Significant

Median Final Temps (°C) with Different Joint Types – 1/0 AWG


Connector Conductor Temp

90 °C 105 °C 120 °C

Compression (Small) >192 >400 >>400

Compression (Big) 113 142 >279

Effect Significance

Connector Large Very Significant

Median Final Temps (°C) with Different Connectors – 1/0 AWG


Summary • Data show connector temps were significantly higher than

conductor in almost all cases. • Data show that connector temps can be much higher than the

Emergency Operating Temperatures (130 °C) specified in cable standards when conductor temps are between 90 °C & 120 °C.

• Connector temperatures were flat or increased with each cycle. • Once many connectors became “hot”, they went into thermal

runaway. • Effects more prominent on 1/0 AWG conductors than 750 kcmil. • Larger connectors run cooler than smaller connectors. • Connectors in heat-shrink joints ran cooler than those in cold-

shrink joints. Temperatures of Connectors Inside MV Joints


Questions ?



temperatures of connectors inside mv joints€¦ · presented to subcommittee b, spring 2015 ieee...

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