developments in diagnosis of high voltage apparatus michael muhr univ.-prof. dipl.-ing. dr.techn....
TRANSCRIPT
Developments in DiagnosisDevelopments in Diagnosisof High Voltage Apparatusof High Voltage Apparatus
Michael MuhrMichael Muhr Univ.-Prof. Dipl.-Ing. Dr.techn. Dr.h.c.Univ.-Prof. Dipl.-Ing. Dr.techn. Dr.h.c.
Institute of High Voltage Engineering and System Management Institute of High Voltage Engineering and System Management University of Technology GrazUniversity of Technology Graz
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
MonitoringRecording of technical
or characteristic values
Evaluation of
these values
Recognition of the condition and
proposal for problem-solving strategies
Analysis
Diagnosis
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Technical Diagnostics - TDTechnical Diagnostics - TD
- Science of recognition of the condition of technical systems
- Aim of TD is to identify, to check and to classify characteristics of the condition of technical systems to change or to influence the condition of these systems
- Quality assurance of technical systems
- Avoidance of an outage of technical systems
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Technical Diagnostic
+ Prevent failure
+ Increase reliability
+ Economic use of equipment
Optimized usage of diagnostic tools
• Technique / method
• Time interval
• Complexity
- Costs
- Effort
- System
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Availability of technical systems
Condition evaluation
Risk evaluation
Technical Diagnostics
MaintenanceRepair Modernization
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Life Life CycleCycle
Lifetime
Condition
„normal“ defect
criticalthreshold
load
pollution
ageing
t
„lifetime extention"by
maintenance
failure
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Stress and Ageing ModelsStress and Ageing Models
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Lifetime Estimation of TransformersLifetime Estimation of Transformers
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Technical Diagnostic EvaluationTechnical Diagnostic Evaluation
Section 1
Section 2
Section 3
100
100
I
C
CO
CR
O
1
4
2 3
5
C ... Condition of the equipmentI ... Importance of the equipmentO ... Equipment 1, 2, 3, 4, 5
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Aim of TDAim of TD
Current condition
Modernization
Original condition
- Monitoring
- Analysis
- Diagnosis
- Preventive maintenance
- Repair
Original condition with ageing
- Ageing behaviour
- Life time
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Tasks of TD
Decision- Continuation of operation- Maintenance- Renewing
Monitoring of equipment Investigations at equipment and models
Life-time behaviourCharacteristic values, current, voltage etc.
Determining of limits Setting of continuous voltage strength
Optimization of life-time
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Bathtub Curve: from statistical analysis
1
6363
D
D
D t
t
t
<1: early failure
=1: stochastic process
>1: ageing process
Weibull Distribution:
Determination of Early FailuresDetermination of Early Failures
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Ageing of an electrical insulation system
Ageing mechanism• Instrinic• Exstrinic• Single stress• Multi stress
Electrical insulation system
Failure
Ageing stress• Thermal• Electrical• Ambient• Mechanical
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
TD at equipment of electrical power engineering
Partial discharge diagnostic• Ue
• Q (pd)• φ (pd)
Thermal diagnostic• Thermovision• Temperature measurement
Mechanical diagnostic• Sound emission analysis• Dilatometry• Mechanical spectrometry• Analysis of mechanical quantities
Dielectric diagnostic• Ue
• u(t)•
C(f)• tan δ(f)
Analytic and spectrometry• UV, VIS, IR - Spectrometry• Gaschromatography• Mass spectrometry
Visual diagnostic• UV - Videography• Thermography• Endoscopy• X-ray graphy
Breakdown diagnostic• Ud
• φ (Ud)• t (Ud)
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Maintenance Strategies - LifetimeMaintenance Strategies - Lifetime
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Blockdiagramm of a Diagnosis SystemBlockdiagramm of a Diagnosis System
Reference components
Excitation• Measuring voltage• Measuring temperature
Control• Voltage• Temperature
Assessment and control unit• Storage of quantities• Run-off control• Data processing
• Input and Presentation• Further processing• Interface
Diagnosis sample• Original• Mode
Data acquisition - Sensors
Stress generation• Voltage• Temperature• Vibrations• Climate
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Non – Destructive TD at Power ApparatusNon – Destructive TD at Power Apparatus
Power apparatus
•Cables
•Solid switchgears
•Capacities •Transformers
•Instrument-transformers
•Rotating machines
•Insulators
•Conventional switchgears
•Circuit breaker
•Gasinsulated switchgears
•Dielectric diagnostic
•Visual TD
•Pd-diagnostic
•Sound emission diagnostic
•Dielectric diagnostic
•Visual TD
•Pd-diagnostic
•Sound emission diagnostic
•Gas analysis
•Dielectric diagnostic
•Visual TD
•Pd-diagnostic
•Sound emission diagnostic
•TD of mechanical quantities
•Dielectric diagnostic
•Visual TD
•Pd-diagnostic
•Sound emission diagnostic
•Leakage current diagnostic
•Visual TD
•TD of thermal and mechanical quantities
•Pd-diagnostic
•Leakage current diagnostic
•Visual TDTD of thermal quantities •Sound emission diagnostic
•Pd-diagnostic
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Basis Aspects of TDBasis Aspects of TD
- Aim
- Technique
- Method
- Quantity
- Connection between quantity and physical / chemical / technical structure of diagnostic sample
- Diagnostic criterion - limit
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Technical DiagnosticTechnical Diagnostic
Thermal
Mechanical
Dielectrical
Partial Discharge
Breakdown
Material analytic
and Spectrometry
Mea
ning
fuln
ess
(str
ess)
Non-destructive
individual testing
Quasi non-destructive
Partly individual testing
Destructive
Type approval test
Random check
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Electrical Diagnostic MethodsElectrical Diagnostic Methods
Partial Discharge
Breakdown
Dielectric
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
• Insulation Resistance
• Capacity and Dissipation Factor
• Isothermal Relaxation Current Analysis (IRC)
• Polarisation / Depolarisation Current Analysis (PDC)
• Frequency Response Analysis (FRA)
Observation and evaluation of interaction of electric fields and material
Dielectric DiagnosticsDielectric Diagnostics
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
U=
I
RS
RO
RD
U=
I
RS
RO
RD
Insulations Resistance Surface Resistance
Insulation ResistanceInsulation Resistance
Guard Ring Arrangement
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Capacity and Dissipation FactorCapacity and Dissipation Factor
CX
RX
CN
PC
DSP
AD
AD
CX
RX
CN
R3 R4 CN
HV
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Analyse in Time DomainAnalyse in Time Domain
V AA
Disch
arg
e V
olta
ge
An
alyse
Disch
arg
e C
urre
nt A
na
lyse
Re
cove
ry Vo
ltag
e A
na
lyse
Ch
arg
ing
curre
nt A
na
lyse0%
20%
40%
60%
80%
100%
120%
PDCIRCPDC RVM
curr
en
tvo
ltag
eSchema
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Isothermal Relaxation Current Analysis (IRC) Isothermal Relaxation Current Analysis (IRC)
V AA
Schema
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Polarisation / Depolarisation Current Analysis (PDC)Polarisation / Depolarisation Current Analysis (PDC)
V AAPolarisation
Depolarisation
Time
Schema
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Frequency Response Analysis (FRA)Frequency Response Analysis (FRA)
U, I U, I
HV LV
0.0001
0.001
0.01
0.1
1
10 100 1000frequency [kHz]
In/O
ut
normal
defect
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Breakdown DiagnosticBreakdown Diagnostic
HV-AC
96
98
100
102
104
106
108
1 6 11 16 21 26 31 36 41 46 51
Attempt
Vo
ltag
e [k
V]
Voltage [kV]96 98 100 102 104 106 108
Pro
babi
lity
[%]
12
510
2030
50
7080
9095
9899
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Breakdown Test with Insulating Oil Breakdown Test with Insulating Oil
0
20
40
60
80
100
1 2 3 4 5 6test series
mea
n va
lue
(kV
)
0
20
40
60
80
100
coef
ficie
nt o
f var
iatio
n (%
)
0.5kV/s mean value 0.5kV/s coeff. of variation2kV/s mean value 2kV/s coeff. of variation5kV/s mean value 5kV/s coeff. of variation
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Partial Discharge (PD) MeasurementPartial Discharge (PD) Measurement
Sensitive nondestructive method as important diagnostic tool
for evaluation of the insulation condition
PD-defect
Location and Detection
Electrical Non electrical methods
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Partial Discharge DiagnosticPartial Discharge Diagnostic
Optical
Electrical
Mechanical
Chemical
IEC 60270
HF/VHF/UHF
Acoustic
Opto-acoustic
HV
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
• Conventional electrical measurement
• Integration at frequency domain
• Narrow-band
• Wide-band
• Integration at time domain
G
ZFilter
HV-Source
Test object
Coupling capacitor
PD-System
HVmeasure
PDPulse
QuadripoleMeasuring impedance
PD-Detection Methods PD-Detection Methods IEC 60270IEC 60270
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
PD-Measurement ResultsPD-Measurement Results
Phase correlated
Single impulses
Time correlated
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
PDC AnalysePDC Analyse
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Unconventional PD-DetectionUnconventional PD-Detection
Rd
ST
CC
VP
W
Rd
ST
CC
W
RPA1
HST1
AMP
SYNC
ICM
LWL
Signal-conversion
acoustic
optical
Oscilloscope
ADU
electrical Surface
Fibre in oil/board
LWL fibre
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
PD-Detection MethodsPD-Detection Methods
• Electrical measurements with high frequencies
- HF / VHF method – 3 MHz to 300 MHz
- UHF method – 300 MHz to 3 GHz
• Acoustic measurements – 10 kHz to 300 kHz
• Optical measurements – ultraviolet – visible – infrared range
• Chemical measurements
- Optical- Chemical
Directional microphone
PD
HV - Acoustic
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
HF / VHF – PD-MeasurementHF / VHF – PD-Measurement
measurement impedance
cable
HV source
PD-signal
inductive
galvanic
PD-signal
current
wire sheath
cable cable
PD-signal
Rogowski coil
PD-signal
sheath interruption
measurement impedance
cable
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Rogowski coil
PD Analyser
Measuring for HF – PD-detection on machines, VHF – PD-coupler, Split ring Rogowski coil
Rogowski coil
HF / VHF – PD-MeasurementHF / VHF – PD-Measurement
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Principle of the coupler sensor
HF / VHF HF / VHF –– PD-Measurement PD-Measurement
2
1
3direct. coupling A B
direct. coupling C D
impulsesource / - No.
signal at coupling output
A B C D
joint /1 – X X –
left cable / 2 X – X –
right cable / 3 – X – X
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
low-pass filter Peak detector
PD measuring instrument
PRPD pattern
Wide bandNarrow band
Spectrum analyser
amplifiers
UHF – PD-measurement
UHF – PD-MeasurementUHF – PD-Measurement
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
- Mobile UHF-window sensor
- Conventional UHF-sensors
Disc sensor Cone sensor
Conductor
Cage
Dectector
Field grading electrodes
UHF – PD-SensorsUHF – PD-Sensors
Conductor
Cage
Detector
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
L1
Schematic arrangement
Sensor 1
Pre amplifier
Measuring instrument
L2
Sensor 2
1 ... Sensor 12 ... Sensor 2
Time delay
Zeit
Am
pli
tud
e
1
2
UHF – PD-Fault LocationUHF – PD-Fault Location
Defect
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
SF6
Air
Box
AE Sensor
Acoustic – PD-MeasurementAcoustic – PD-Measurement
• Acoustic Partial Discharge Detection
• Acoustic signal as a result of the pressure wave produced by PD
• Frequency spectrum 10 Hz up to 300 kHz
Principle schematic to the acoustic PD-detection
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Acoustic – PD-SensorsAcoustic – PD-Sensors
HV
Time delay
SensorPD
Time
Sig
na
l
Directional microphone
PD
HV
- Piezo-electric (sound emission) - Condenser microphones- Structure-born sound-resonance - Accelerometer- Opto-acoustic-sensor
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
amplifierOscilloscope
AE SensorPD-Detector
Filter
A/D Converter
Acoustic – PD-detection system
Acoustic – PD-MeasurementAcoustic – PD-Measurement
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Experimental setup of the optical interferometric detection of PD
Opto-Acoustic – PD-MeasurementOpto-Acoustic – PD-Measurement
Laser
Reference optical fibre coil
Sensing optical fibre coil
Oil tank
High Voltage
PD-source
Detector
Beam Splitter
Beam Splitter
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Measuring circuit after IEC 60270 and optical measuring system
Optical fibre with lens
Optical fibreLens
Peak
Medium oil
Observation area
Fluorescent optical fibre
conventional opt. fibre
Peak
fluorescent opt. fibre
Plate
PD – Optical DetectionPD – Optical Detection
Rd
PC
LWL
M
ST
CC
VP
PRW
IEC 270
optical system
Oscilloscope,
ADU
Signal-conversion
Voltage supply
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Emission spectrum of corona discharges in SF6
340 450 560 670 780 nm 340 450 560 670 780 nm 340 450 560 670 780 nm
Test arrangement for optical PD-measurement
SF6
Photomultiplier
Conv.PD Detector
ADU
I/U
Oscilloscope
Optical – PD-Detection in GISOptical – PD-Detection in GIS
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Operation diagram camera DayCor IITM and application
Optical – PD-MeasurementOptical – PD-Measurement
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
PD – ApplicationPD – Application
UHF- GIS- GIL- Transformer monitoring
HF / VHF- High voltage cables- Transformers
Acoustic- High voltage cables- GIS- Transformers- Overhead lines
Optical- GIS- Overhead lines
Chemical- GIS- Transformer- Machines
Electrical-Transformers- GIS- Machines - GIS- Overhead lines- ...
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Data input and
monitoring unit
ReportDisplayData archiving Real time
announcementAlarm Data transfer Trend analysis
ModemTelephone lines PC station
Monitoring, Data Processing, AnnouncementMonitoring, Data Processing, Announcement
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Signal processing
ReportDisplay Data store Data transfer Trend analysis
Example for signal processing
Pattern RecognitionPattern Recognition
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
PD-Evaluation
Loss Factor
Insulation Resistance
FRA-Analysis
PD Location
Partial Discharges
Insulation
Signal Analysis
Transfer Function
Wavelet Technique
RVM, FDS Analysis
Endoscopy
Dynamics
Oil Stream
Transient Oil Pressure
UHF PD-Detection
Operating Noises
Acoustics
Oil Analysis
Moisture
Furane Values
IEC 599
IEEE C57.1041991
Dörnenburg
Rogers
Duval
Other Methods
Dissolved Gas Analyses (DGA)
Neutralization Value
Elektrisch
Mechanisch
Thermisch
ElectricalOptical
Mechanical
Chemical
Thermal
Thermography
Temperature Monitoring
Operating Temperature
Eye
PDC-Analysis
Fibre Optics Loss Factor
Breakdown VoltageOil Analysis
DAC-PD-Measurement
Power Transformer DiagnosticsPower Transformer Diagnostics
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Method Information Comment
Oil analysis OA Oil ageing, insulation property Routine
Gas-in-oil analysis DGAOil and paper ageing, flashovers, PD,
hot spotsRoutine
Loss factor (Dielectric dissipation factor)
tanδ Dielectric losses in the insulation system Routine
Furane values FA Ageing of the paper insulation Condition determination
Degree of polymerization
DP Ageing of the paper insulation Condition determination
Partial discharges PDPaper ageing, ageing of the
insulation systemCondition determination
Polarisation anddepolarisation
currentsPDC Water content in the paper insulation Condition determination
Infraredmeasurements
IR Overload, failure of the cooling systemCondition determination
and for fault location
Acousticmeasurements
AM PD-detection and location For fault location
Frequency response FRA Mechanical condition of the windings After short circuits
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Bre
akd
ow
n v
olta
ge
[kV
]
Water content [ppm]
dilution emulsion
tief
hoch
tief
hoch
Water content in oil
Wa
ter
con
ten
t in
pa
pe
r
Temperature
High
Low
Moisture
• Karl-Fischer titration
• Capacitive sensors
• Breakdown voltage
• PDC
Oil AnalysisOil Analysis
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Loss Factor (tanδ)
• Heat losses are temperature-dependent
• High loss factor – thermal breakdown
• Limit: tanδ ≤ 5 %by T=100° C
Temperature dependace of tanδ for new oil (1) and oils in operation (2,3,4)
Oil AnalysisOil Analysis
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Dissolved Gas Analysis (DGA)
• Key gases: hydrogen, methane, ethane, ethylene, acetylene, propane, propylene, carbon monoxide, carbon dioxide
• Detectable failures: thermal and electrical failure
Oil AnalysisOil Analysis
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Oil AnalysisOil Analysis
DGA - Evaluation
• CIGRE
• IEC
• IEEE
• Dörnenburg
• MSS / VDE-Diagnosis
• Rogers
• Duval
• Laborelec
• KEPCO
Duval triangel
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Paper AnalysisPaper Analysis
Polymerisation degree (DP)
- In direct correlation with the mechanical strength
new paper DP 1000 – 1200
paper at the end of life time DP approx.200
- A decrease in the DP value furane is going hand in hand with an increase of components
- Furane dependence
• Oil temperature • Type of oil
• Neutralization factor • Type of paper
• Sludge content • Moisture content of oil and paper
• Ratio oil / paper
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Furane Analysis
• Condition of paper insulation (mechanical strength) determined by degree of polymerization
• High performance liquid chromatograph (HPLC)
Oil AnalysisOil Analysis
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
• Conventional
• Acoustic
• Optical
• Chemical
• Electrical
• New Systems: electromagnetic wave detection,transfer functions, damped AC voltage (DAC)
Partial DischargesPartial Discharges
Measurementin laboratory
conventionalmeasurement
IEC 60270Acoustic
PD - measurement
OpticalPD - measurement
ChemicalPD – measurement
(DGA)
electricalHigh frequency
PD - measurement
Narrow bandΔf ~ 10 kHz
Broadband Δf ~ 50 - 500 kHz
HF/UHFmethod
f ~ 10 - 500 kHz
Narrow bandΔf < 2 MHz
Measurementon-site
UHFmethod
f ~ 0,2 - 2 GHz
BroadbandΔf > 50 MHz
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Dielectric DiagnosisDielectric Diagnosis
Charging and discharging measurements
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Diagnostics with Transient Test VoltagesDiagnostics with Transient Test Voltages
• Frequency response analysis (FRA) and transfer function
• Low voltage impulse response (LVI)
• Wavelet analyse
• DAC-PD-measurement
FRA
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Thermal and Optical Diagnostic MethodsThermal and Optical Diagnostic Methods• Thermography
• Temperature measurement with fibre optics
• PT-100 elements
• Surface acoustic wave radio transponder
• Visual inspection
• Endoscopy
OKULAR
LICHTQUELLEFLEXIBLES ENDE
BLICKBEREICH
Ocular
Light source Flexible end
Field of vision
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Mechanical Diagnostic MethodsMechanical Diagnostic Methods• Transient oil pressure (short circuit)
• Stream analysis (oil and cooling air)
• Acoustic PD-locating
StreamNostream
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Diagnosis of Rotating MachinesDiagnosis of Rotating Machines
Tasks • Thermal monitoring
• Air cooling analysis
• Monitoring of vibrations
• Acoustic monitoring
• Chemical-analytic monitoring
• Magnetic monitoring
• Electrical monitoring
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Rotating MachinesRotating Machines- Electrical Diagnosis Methods
• Impulse voltage test at windings
L
R
2
SCL.
1
teUtu t cos.. .
Attenuation factor
Resonance frequency of resonating circuit
tu - Oscillogram of a decaying oscillation
a) Error –free
b) faulty
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Rotating MachinesRotating Machines
- Dielectric Diagnosis
• Time domain
- Insulation resistance Riso
- Insulation current iiso = f (t)
• Frequency domain
- Capacitance
- Loss factor tan = f (), C, U
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
(1) Dry condition(2) Humid condition(3) Dryness limit curve
Cooling
Heating
Rotating MachinesRotating Machines
- Dielectric Diagnosis
Insulation time constant 10 as criterion for the dryness limit curve 10 = Riso (600s) x C (50Hz)
10 = f ()
Insulation time constant in dependance of the slot temperature and the insulation condition
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Rotating MachinesRotating Machines
- Partial discharge (Pd) diagnosis
• Pd’s
- In cavities of solid insulation
- In the are of the end winding
- At no-perfect working protect system of mica
- At vibrating parts of winding
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Physical Condition of WindingsPhysical Condition of Windings
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Discharge behaviour within Machine WindingsDischarge behaviour within Machine Windings
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Thermography as Diagnostic ToolThermography as Diagnostic Tool
• Requirement
- Increasing efficiency of power grid
- Decreasing of inspection and maintenance rate
• Load situation
- Increasing electrical power consumption
- Higher loads on equipment
• Demand of ON-line diagnostic tools
E.g. Contact less temperature measurement
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Thermography as Diagnostic ToolThermography as Diagnostic Tool
Material/Structure
Heat GenerationTemperature
Surface temperature
Surface tem
perature
Surface temperature
power output
powe
r outpu
t
power outputSurrounding
• Load currentResistor
• VoltageConductivityDielectric losses
Temperaturemeasurement
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Isolated Transmission
Temperature MeasurementTemperature Measurement
High Voltage
ObjectTemperature
SensorCoupling SignallingTransmissionpower supply
Isolated Coupling
High Voltage
ObjectTemperature
SensorCoupling SignallingTransmissionpower supply
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Spot Temperature MeasurementSpot Temperature Measurement
Transformer
29.8°C29.7°C29.8°C29.6°C29.7°C29.9°C29.8°C29.7°C29.6°C29.5°C30.0°C29.7°C29.9°C29.7°C29.7°C30.1°C29.9°C29.9°C29.7°C29.8°C30.0°C30.0°C30.0°C29.9°C29.8°C
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Temperature DistributionTemperature Distribution
Hot
Cold
33°C 23°C
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Thermography in HV - SystemsThermography in HV - Systems
- Applications
• Connections
• Switches
• Power transformers
• Measuring transformers
• Overhead lines
• Cable terminations
• Bushings
• Fuses
• Rotating Machines
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Applications of ThermographyApplications of Thermography
Poor contact resistance of a joint
Poor contact resistance of a disconnector
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Applications of ThermographyApplications of Thermography
Compression connector of an overhead line
Asymmetrical energy flow of a cable
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Applications of ThermographyApplications of Thermography
Bearing, machines
© FLIR
Slip-ring brushes
M. Muhr
Institute of High Voltage Engineering and System ManagementInstitute of High Voltage Engineering and System Management
Thank You for Your Attention Thank You for Your Attention