SOLUTION FOR THE WEAK LINKSOLUTION FOR THE WEAK LINK

HIGH VOLTAGE BOLTEDHIGH VOLTAGE BOLTEDCOUPLERS AND ADAPTORSCOUPLERS AND ADAPTORS

HIGH VOLTAGE COUPLERS REGARDEDHIGH VOLTAGE COUPLERS REGARDED AROUND THE WORLD AS THE WEAK LINK AROUND THE WORLD AS THE WEAK LINK

• Couplers have been Failing in Service• Failures were Unpredictable• Cause of Failures Unknown

• Decrease in Safety and Health• Decrease Production• Increase Operation Costs

WHY?WHY?

ASSOCIATED PROBLEMSASSOCIATED PROBLEMS

ACARP REPORT ON THE FAILUREACARP REPORT ON THE FAILURE OF 11kV PLUGS AND ADAPTORSOF 11kV PLUGS AND ADAPTORS

• Australian MiningAustralian Mining Industry ConcernedIndustry Concerned

• Invested Through ACARPInvested Through ACARP

EXAMPLES OF FAILED COUPLERS IN SERVICEEXAMPLES OF FAILED COUPLERS IN SERVICE

1

2 3

45 6

CREATING DEAD SHORTCREATING DEAD SHORT

SHORTSHORT

Australia South AfricaUSA Canada

RESEARCHING COUPLERS GLOBELY RESEARCHING COUPLERS GLOBELY

Research showed that all the designs were very similar. These similarities were:

• Insulators were all of a tower design

• When closed, all suffered from air being trapped around the insulator profile

• The same design flaws were present in all types of couplers

ACARP PROJECT C5032ACARP PROJECT C5032

Research into the Failure of 11kV Plugs and Adaptors used in Underground Coal Mines

Quote: Executive Summary:“A number of design weaknesses were identified that lead

to the generation of partial discharges within the assembled plug and adaptor”

DESIGN FLAWS FOUNDDESIGN FLAWS FOUND

• Large Volume Of Air Trapped Inside Coupler Enclosure

• High Discharge Creates Corona• Corona Converts Air To Ozone• Ozone Is A Conductor• Phase To Phase Flashover

AIR AND PARTIAL DISCHARGEAIR AND PARTIAL DISCHARGE

AIR

PARTIAL DISCHARGE

SOLUTIONSSOLUTIONS

• Remove Air with Silicon Rubber Insert

• Insulating Material Developed to Extinguish TrackingInsulating Material Developed to Extinguish Tracking

SiliconSiliconInsertInsert

InsulatingInsulatingMaterialMaterial

NO TRIPS OR ANY SIGNS OF FAULTNO TRIPS OR ANY SIGNS OF FAULT

PHASE SEGREGATION BY EARTHPHASE SEGREGATION BY EARTH

PHASE

PHASE

PHASE

Mining Industry Standard

EARTH

EARTH

EARTH

EARTH

A Phase to GroundFault was createdwith conductive

paint

Earth Star Placed Between Phases

A Through Fault Test was then performed on this solutionto see how it would perform in the field

FIRST SOLUTIONFIRST SOLUTION

REASON FOR FAILUREREASON FOR FAILURE

PHASE 1

EARTH

PHASE 2

PHASE 3

FINDING A SUCCESSFUL SOLUTIONFINDING A SUCCESSFUL SOLUTION

.

Equipotential Lines Good

Earth StarEarth StarEquipotential Lines Equipotential Lines

Crushed UpCrushed Up

Individually ScreenedIndividually ScreenedCableCable

EquipotentialEquipotentialLines GoodLines Good

SOLUTIONSOLUTION

New Design expels all airin face of coupler and phases

are segregated by ground

SEPARATESEPARATEINSULATORSINSULATORS

BODY SEGREGATESBODY SEGREGATESPHASESPHASES

EXPELS ALL AIREXPELS ALL AIR

• ALL TYPE TESTS PERFORMED WERE ALL TYPE TESTS PERFORMED WERE WITHIN CABLE SPECIFICATIONSWITHIN CABLE SPECIFICATIONS

COUPLERS HOMOGENEOUS COUPLERS HOMOGENEOUS WITH CABLEWITH CABLE

EARTHEARTH

COMPARISONCOMPARISON

ACARP PROJECT C5032ACARP PROJECT C5032

Research into the Failure of 11kV Plugs and Adaptors used in Underground Coal Mines

Quote: NEW DESIGN “Given the nature of the newdesign and the high voltage stress management issues thatit addresses, it is expected that other manufacturers willfollow this lead and produce their own variations of thedesign. “

PEACE OF MINDPEACE OF MIND

ANALYZING THE DESIGN ADVANTAGESANALYZING THE DESIGN ADVANTAGES

Increased Safety Increased ReliabilityIncreased Reliability Increased ProductivityIncreased Productivity Increased SecurityIncreased Security