Optical technologies in the power industry:Monitoring and diagnosis of gas-insulatedelectrical switchgear

Thomas A. Paul, ABB Corporate Research, Switzerland

Outline

Ø Electrical switchgear and gas insulation

Ø Insulation gas diagnostics for SF6Ø Insulation gas diagnostics for SF6-alternatives

Ø Electrical switchgear and gas insulation

Ø Insulation gas diagnostics for SF6Ø Insulation gas diagnostics for SF6-alternatives

Electrical SwitchgearElectrical Switchgear

Ø Essential components for energy transmission and distribution.

Ø Necessary at every switching point in the electrical power grid.

Ø Switching devices are associated with control, protection andmetering of power systems.

Ø Essential components for energy transmission and distribution.

Ø Necessary at every switching point in the electrical power grid.

Ø Switching devices are associated with control, protection andmetering of power systems.

Electrical SwitchgearElectrical Switchgear

Ø Air-insulatedsubstations have largespace requirement

Ø Significant reduction infootprint through use ofpotent insulation gases– the best is SF6.

Ø Air-insulatedsubstations have largespace requirement

Ø Significant reduction infootprint through use ofpotent insulation gases– the best is SF6.

380kV GIS and AIS, Pradella CHABB’s ELK-3 GIS

Air-insulated switchgear

SF6-insulated switchgear

SF6 as insulation gasSF6 as insulation gas

Partial discharge [image from www.think-grid.org]

Ø During operation, the gascomposition can change

Ø Humidity ingress throughseals and from outgassing

Ø Arc-induced decompositionduring switching

Ø Partial discharge induceddecomposition

Ø Decomposition products can betoxic and corrosive, and impedeoperability and safety ofswitchgear.

Ø During operation, the gascomposition can change

Ø Humidity ingress throughseals and from outgassing

Ø Arc-induced decompositionduring switching

Ø Partial discharge induceddecomposition

Ø Decomposition products can betoxic and corrosive, and impedeoperability and safety ofswitchgear.

SF6 HV circuit breaker, M. Abrahamsson, ABB

Insulation gas diagnosticsInsulation gas diagnostics

§ Permanent monitoring devices

Ø Density and T-compensated pressure

Ø Humidity

§ Off-line, extractive devices

Ø Humidity

Ø Complete gas composition

§ Leakage detection

§ Permanent monitoring devices

Ø Density and T-compensated pressure

Ø Humidity

§ Off-line, extractive devices

Ø Humidity

Ø Complete gas composition

§ Leakage detection

Gas analysis on a DTB, V. Williams, Company EMT

Humidity sensor on a GIS, Vaisala

SF6 sniffer, CPSOptical chilled mirror dewpoint meter, MBW

Abs

orba

nce

Optical instruments for switchgear diagnosisOptical instruments for switchgear diagnosis

§ SF6 and many decomposition products offer IR signatures

§ These are conveniently used for gas diagnostics

§ SF6 and many decomposition products offer IR signatures

§ These are conveniently used for gas diagnostics

Wavenumber [cm-1] F. Rager, ABB

Commercial optical instruments for switchgeardiagnosisCommercial optical instruments for switchgeardiagnosis

§ Multi-componentanalysis

§ Gas compositionanalysis

§ Sampling & pump-back

§ Integral leakagedetection

§ Photoacousticsensors

§ IR imaging

§ Multi-componentanalysis

§ Gas compositionanalysis

§ Sampling & pump-back

§ Integral leakagedetection

§ Photoacousticsensors

§ IR imaging

EMT IR SF6 analyzer

IR SF6 analyzers, EMT

IR photoacoustic SF6 analyzers, Innova-Lumasense

Innova-Lumasense

SF6-alternatives: insulation gas mixturesSF6-alternatives: insulation gas mixtures

§ Alternatives to SF6 are based ongas mixtures

§ Fluorinated organics (FOs) havehigh break-down strength

§ Performance of SF6-alternativesstrongly depends on composition

§ Composition is prone to change

ØConsumption in arc

ØCondensation

ØOther undesired processes,

§ Alternatives to SF6 are based ongas mixtures

§ Fluorinated organics (FOs) havehigh break-down strength

§ Performance of SF6-alternativesstrongly depends on composition

§ Composition is prone to change

ØConsumption in arc

ØCondensation

ØOther undesired processes,

New measurement instumentation neededNew measurement instumentation needed

Optical monitoring of SF6-alternatives in switchgearOptical monitoring of SF6-alternatives in switchgear

Abs

orba

nce

A. Kramer, ABB

§ Characteristic UV bandsavailable for FOs

§ UV LEDs available downto 200 nm with smallbandwidth

§ Can use straight-forwardabsorption measurement

§ Characteristic UV bandsavailable for FOs

§ UV LEDs available downto 200 nm with smallbandwidth

§ Can use straight-forwardabsorption measurement

Intensity

Optical monitoring of SF6-alternatives in switchgearOptical monitoring of SF6-alternatives in switchgear

§ Challengingmeasurementenvironment

ØDust

Ø Vibration

ØCorrosive gases

§ Optical absorptionmeasurementnevertheless viable

§ Accuracy betterthan 1% ofmeasuredconcentration

§ Challengingmeasurementenvironment

ØDust

Ø Vibration

ØCorrosive gases

§ Optical absorptionmeasurementnevertheless viable

§ Accuracy betterthan 1% ofmeasuredconcentration

Optical probe

A. Kramer andM. Porus, ABB

SummarySummary

Ø Optical technologies areused widely forinsulation gas diagnosis

Ø Diagnosisinstrumentation isestablished for mostaspects related to theuse of SF6

Ø SF6-alternatives requirenew solutions

Ø Optical technologies areused widely forinsulation gas diagnosis

Ø Diagnosisinstrumentation isestablished for mostaspects related to theuse of SF6

Ø SF6-alternatives requirenew solutions