OPTIONS FOR MANAGING SAFETY WITH ELDERLY SWITCHGEAR

Richard Blakeley, R.P.S. Switchgear,

SWITCHGEAR – WHAT DOES IT DO? MAKE AND BREAK NORMAL LOAD CURRENTS

OPERATE CONTINUOUSLY UP TO NORMAL RATINGS

WITHSTAND THE PASSAGE OF THROUGH-FAULT CURRENT FOR SUFFICIENT TIME TO ALLOW THE DOWNSTREAM PROTECTION TO OPERATE

SAFELY SWITCH ON TO FAULT, HANDLING THE ENERGIES INVOLVED

SAFELY INTERRUPT FAULT CURRENT AND THEREBY REMOVING THE FAULTED EQUIPMENT FROM THE SOURCE OF ELECTRICAL SUPPLY

ACT AS A POINT OF ISOLATION AND EARTHING TO ENABLE WORK TO BE DONE SAFELY

Reyrolle, Type ‘AR’ 33kv, 800A Switchgear,

PRIMARY CONTACTS -- FIXED AND MOVING.

ARCING CONTACTS -- FIXED AND MOVING.

CLOSING MECHANISM -- (Stored Energy, MO or Manual),

OPENING MECHANISM -- STORED ENERGY

PRIMARY INSULATION SYSTEM,

ENCLOSURE,

MEANS OF ISOLATION FROM THE SYSTEM.

CIRCUIT BREAKER DESIGN -- TRADITIONAL

COMPONENTS

Risk Factors with Elderly Switchgear

AGING SWITCHGEAR – RISKS & ISSUES

Lack of knowledge/training

Network changes resulting in the switchgear being overstressed

Not being modified as per manufacturer’s advice/updates

Not being maintained or operated properly

Dependent-manual switchgear

Spares & Technical Support not being available

Age related failure,

Switchgear is normally ‘quiescent’

Continuous assessment not justifiable

True condition difficult to determine

ELDERLY SWITCHGEAR – TRUE CONDITION??

“In on-site evaluation tests carried out by Reyrolle on aging oil switchgear worldwide, it was found that on more than 50% of oil switchgear thought to be in good condition, the circuit breakers had faults or were operating outside of their design envelope and in some cases would have failed to operate correctly under system fault conditions”

SWITCHGEAR FAULT CLEARANCE – KEY FUNCTION FOR SAFETY

ISSUES WITH ELDERLY SWITCHGEAR

ELDERLY OIL SWITCHGEAR PRESENTS INCREASING RISK , (Consequences of a flashover can be severe)

CONDITION ASSESSMENT OF DISTRIBUTION SWITCHGEAR IS DIFFICULT

SPARES ARE NOT AVAILABLE FOR MOST ELDERLY SWITCHGEAR,

NOT UPGRADED TO LATEST REVISION,

NOT COMPLIANT WITH MODERN SAFETY STANDARDS,

SWITCHING PERFORMANCE OF OIL CB’s NOT GOOD AT LOWER FAULT LEVELS,

Internal Arc/Arc Flash Faults

ARC FLASH FAULTS

HOW OFTEN DO THEY HAPPEN?

“EVERY DAY, 1 TO 2 ARC FLASH RELATED FATALITIES OCCUR ACROSS NORTH AMERICA”

INTERNAL ARC FAULTS – CAUSES

Badly Designed Switchgear Incorrect Installation Insulation Failure

▫ Contamination

▫ Age Deterioration

▫ Overstressing

▫ Human Intervention

▫ Vermin Ingress

Lack of/Inadequate Maintenance Human Error or Misuse Over-stressing

ENERGY RELEASED BY ARC FAULT

PRESSURE RISE

VISUAL & ACCOUSTIC

PHENOMENA

TEMPERATURE RISE

EFFECTS OF FAULT ARC

CONSEQUENCES FOR PLANT

MECHANICAL STRESSING OF ENCLOSURES

THERMAL STRESSING, MELTING, VAPOURISATION

CONSEQUENCES FOR PERSONNEL

SHOCK WAVE, FLYING DEBRIS, OPENING PANELS

EJECTION OF FLAMES & HOT GASES, METAL

VAPOUR

EFFECTS AND CONSEQUENCES OF AN ARC FAULT IN HIGH VOLTAGE SWITCHGEAR

THE CONSEQUENCES OF AN INTERNAL ARC

FAULT IN HV SWITCHGEAR

THE CONSEQUENCES OF AN INTERNAL ARC

FAULT IN HV OIL SWITCHGEAR

ARC-FAULT IN NON-VENTED SWITCHGEAR

SOME INTERESTING DATA FROM RPS TESTING OF ELDERLY SWITCHGEAR

Current starts: 0 Pressure starts: 0.4 ms Pressure peak: 4.7 ms Pressure duration: 6.6 ms Current peak: <10 ms

Data & Test evidence supports that the covers will be flying off in 5 – 10 ms

Maximum pressure on switchgear panels/doors can be 1-2 bar

Safety Solutions & Improvements for Existing Switchboards

TO IMPROVE SAFETY FOR OPERATORS AND STAFF,

TO REDUCE MAINTENANCE AND LIFETIME OWNERSHIP COSTS,

TO IMPROVE THE RELIABILITY AND THE SERVICE-ABILITY OF THE CIRCUIT BREAKERS.

TO INCREASE THE RATING OF THE SWITCHBOARD, (X/R, Normal & Short cct)

TO FURTHER EXTEND THE REMAINING LIFE OF THE ASSET BY REPLACING KEY COMPONENTS AS REQUIRED, (BUSHINGS, CT’S, VT’S ETC)

TO MODERNISE THE CONTROL & PROTECTION EQUIPMENT.

TO ACHIEVE THE ABOVE WITH MINIMUM SYSTEM DISRUPTION.

KEY STRATEGIC OBJECTIVES FOR LIFETIME SUPPORT OF AGING SWITCHGEAR ASSETS.

SUMMARY OF SWITCHGEAR SOLUTIONS,

SAFETY RETROFITS,

CIRCUIT BREAKER RETROFIT,

ARC DOOR + END SHIELD RETROFIT,

3-SIDED ‘CONTAINMENT’

‘REMOTE OPERATION’

UPGRADES & LIFE EXTENSION,

CURRENT TRANSFORMER REPLACEMENT,

CABLE BOX RETROFIT,

REPLACEMENT OF ORIFICE BUSHINGS,

REPLACEMENT OF VT’s

PROTECTION & CONTROL UPGRADE,

Circuit Breaker Retrofit

CIRCUIT BREAKER RETROFIT

Existing LMT panel

Oil Circuit Breaker out

Vacuum Circuit Breaker in (Brand new unit)

OCB TO VCB REPLACEMENT ABOUT A DAY PER CIRCUIT

MINIMAL DISRUPTION

SIGNIFICANT SAFETY IMPROVEMENT

>6,000 units in service world-wide

RETROFIT CIRCUIT BREAKER FOR REYROLLE ‘LM’ SWITCHGEAR

SIMPLE MODULAR DESIGN

PROVEN CAST EPOXY RESIN INSULATION SYSTEM

CAPABLE OF MORE THAN 10,000 LOAD CURRENT OPERATIONS

PROVEN LONG LIFE, LOW MAINTENANCE MECHANISM

LESS THAN 30% OF THE PARTS OF LMT

CAPABLE OF OVER 50 SHORT-CIRCUIT OPERATIONS AT 25KA AT 12KV

EXCELLENT SWITCHING PERFORMANCE, (25ms opening, >45% dc component)

DIRECT REPLACEMENT FOR LM RANGE,

SIGNIFICANTLY IMPROVES SAFETY IN THE SUBSTATION,

LESS THAN 1 DAY PER CIRCUIT, (Fast Implementation, minimum disruption)

SHORT CIRCUIT WITHSTAND RATING OF THE SWITCHBOARD CAN BE INCREASED UP TO 31.5kA ,

REMOVES OIL HANDLING,

REPLACES CB WITH LONG LIFE, LOW MAINTENANCE UNIT,

LOW COST W.R.T. COMPLETE SWITCHBOARD REPLACEMENT, (<30%)

ALLOWS SUBSTATION ASSETS TO BE RENEWED & REVALUED COST EFFECTIVELY,

RPS LMT SWITCHGEAR RETROFIT -- SUMMARY

FURTHER SAFETY FOR EXISTING SUBSTATIONS

“REPLACEMENT OF THE O.C.B. WITH OUR VACUUM UNIT IS A SIGNIFICANT

IMPROVEMENT IN OPERATOR SAFETY”

BUT THERE ARE OTHER IMPORTANT SAFETY FEATURES THAT ARE AVAILABLE TO

SIGNIFICANTLY IMPROVE SAFETY AND BRING THE EXISTING SWITCHBOARD TOWARDS

62271-200 FOR INTERNAL ARC SAFETY”

FURTHER SAFETY FOR EXISTING SUBSTATIONS

SWITCHGEAR SAFETY UPGRADES:

Arc-proof doors + end shields

3 sided containment

Electrical operation ‘not-in-front’

EXISTING SWITCHGEAR & INTERNAL ARC SAFETY

EXISTING SWITCHBOARDS HAVE NO INTERNAL ARC WITHSTAND OR PRESSURE RELIEF DESIGN,

HUMAN PRESENCE IN FRONT OF THE LIVE SWITCHBOARD IS UNAVOIDABLE

SAFETY FOR OPERATORS, STAFF AND VISITORS IN FRONT OF THE EXISTING SWITCHBOARD IS ACHIEVABLE,

RACKING THROUGH A CLOSED ARC-PROOF DOOR IS ESSENTIAL.

TYPICAL EXISTING LMT SWITCHBOARDS

WHY HAVE AN ARC-PROOF DOOR?

WHY HAVE RACKING THROUGH AN ARC-PROOF DOOR?

TWO IMPORTANT QUESTIONS:-

EXISTING SWITCHGEAR & INTERNAL ARC SAFETY

WHY HAVE AN ARC-PROOF DOOR?

LMT TEST ARRANGEMENT

STANDARD LMT PANEL

FAULT IN BREAKER COMPARTMENT

25KA, 1S DURATION

OCB WOULD BE MUCH WORSE

WHY HAVE AN ARC-PROOF DOOR?

...from a different angle

WHY HAVE RACKING THROUGH AN ARC-PROOF DOOR?

BEHIND CLOSED DOOR RACKING

RETROFIT ARC-PROOF DOOR – OPERATOR SAFETY

Behind Closed Door Racking

RETROFIT END SHIELDS – OPERATOR SAFETY

PREVENTS BURN-THROUGH,

PROVIDES LATERAL SAFETY

SIMPLE INSTALLATION

NO BUS OUTAGE REQUIRED

END PANEL CCT OUTAGE ONLY

RETROFIT OF , 25kA, 1s ARC WITHSTAND FRONT DOOR & END SHIELDS FOR OPERATOR SAFETY`

LMT SWITCHBOARDS RETROFITTED WITH ARC DOORS & END SHIELDS. END SHIELD.

RETROFIT OF ARC-WITHSTAND FRONT DOOR

Brunei Australia

South Africa

United Kingdom

ARC DOORS REDUCE THE HRC – NFPA 70E

Activity Existing switchgear

With arc-doors & end shields

Circuit breaker operation 4 0/1

Circuit breaker racking 4 0/1

Instrument cubicle work/inspection 4 0/1

Maintenance work in front of switchboard 4 0/1

Relay inspection/testing 4 0/1

General presence in the switch-room in front of the switchboard 4 0/1

3-SIDED CONTAINMENT SYSTEM

3-SIDED CONTAINMENT SYSTEM

TEST ARRANGEMENT

LMT PANELS FITTED WITH ARC WITHSTAND KIT

FAULT IN BREAKER COMPARTMENT

25KA, 1S DURATION

CERTIFIED TO IEC 62271-200

3-SIDED SAFETY, 2.8M ROOF

ARC DOOR TEST TO LATEST STANDARD

‘REMOTE’ OPERATION

Option 1 – Remote Control Panel • Dedicated control for each panel • One set of trip & close operators with key to

determine panel

Option 2 – Remote Control Pendant • Lead length: 10m, 15m or request • Plugs into panel to be operated

Other Retrofit & Upgrade Solutions

RETROFIT OF CT CHAMBER & CABLE BOX

PITCH-FILLED CABLE BOX REPLACED WITH AIR

CABLE BOX.

ENCAPSULATED CAST RESIN CT’s REPLACED WITH SLIP-OVER TYPE

RETROFIT OF CT CHAMBER

SLIP-OVER CT RETROFIT KIT FOR LMT

ASSEMBLED, JIGGED AND POURED IN THE FACTORY

COMPLETE INSTALLATION

REPLACES THE CABLE BOX & CABLE BOX BUSHINGS ONLY, -- OR

ALSO REPLACES THE EXISTING CAST RESIN CT’S WITH SLIP-OVER TYPE,

INCLUDES NEW CT ORIFICE BUSHINGS AND CT BUSHINGS,

IMPROVED FUTURE PROTECTION FLEXIBILITY,

LIVE LINE INDICATION & PHASING AVAILABLE,

CONVERTS EXISTING CAST PITCH-FILLED BOX TO AIR TERMINATION,

EASY TO IMPLEMENT, -- PER CCT OUTAGE ONLY,

CABLE BOX REPLACEMENT 400A/800A FEEDER PANEL CONVERTED TO AIR BOX.

400A/800A FEEDER PANEL BEING CONVERTED TO AIR

BOX.

VT REPLACEMENT – MOVING PORTION

RPS manufacture & supply a direct replacement truck for the existing Reyrolle LMT VT’s

Fast replacement – no bus-bar outage required Isolating and Engaging the VT through the Instrument

cubicle is available for the new VT arrangement

Replacement VT trucks for LMT

PROTECTION & CONTROL UPGRADE

Replaces the existing RMI “top-box”

Complete new RMI modernisation

Equipped, wired & tested in the factory

Customised to specific customer requirements

Simplifies site work

LMT SWITCHBOARD FITTED WITH SAFETY, PROTECTION & CONTROL IMPROVEMENTS

LMT SWITCHBOARD FITTED WITH RPS IMPROVEMENTS

RETROFIT VCB’S,

RETROFIT ARC DOORS

PROTECTION & CONTROL UPGRADE,

RETROFIT RMI CUBICLES,

CT & VT UPGRADES,

SWITCHBOARD FAULT RATING INCREASED FROM 13.1kA UP TO 31.5kA.

“Upgraded to modern standards for 40% of the cost of switchboard replacement”

SUMMARY – ELDERLY SWITCHGEAR RETROFIT OPTIONS

SAFETY UPGRADES: OCB to VCB upgrade Arc-proof doors + end shields 3 sided containment Electrical operation ‘not-in-front’

ADDITIONAL RETROFITS: RMI cubicles Busbars VT’s – bus and circuit CT’s Cable boxes

Existing aged switchgear can be made safer & upgraded