h41 s. Tenbohlen

MATPOST MATPOST 20032003Untertitel (Arial 22 bis 24)

- Einfügen des hervorzuhebenden Textes -- Einfügen des hervorzuhebenden Textes -

Benefit of Sensors foron-line Monitoring Systems

for Power Transformers

T. Stirl, S. Tenbohlen, M. Rösner

Monitoring Systems - Monitoring Systems - 22© 2003 ALSTOM© 2003 ALSTOM

Failure

TroubleshootingOutage Time: 1 day ... 3 weeks

Refurbishment / ReplacementOutage Time: 1 ...12 months

Time and Cost Consuming

On-line Monitoring

Condition Assessment

Condition-Based Maintenance

Cost Effective & Reliable

Monitoring System MS 2000

Error Diagnosis Condition Diagnosis


Failures of Transformers

Bushing 14%

Auxiliary

5%

OLTCWinding

30%

Core

5%Tank

6%

Cigre SC 12 WG 12.05Electra, No.88, 1983

40%

Use of Comprehensive Monitoring System


Voltage Sensor

Oil Presssure SensorPeak-Sampler

3 Phase Voltages

Oil Pressure

Measuring Quantities Benefit Operational Voltage Overvoltages Leakage Current Change of Capacitance Change of Oil Pressure

Bushings



Bushings – Change of CapacitanceDetection of Partial Flashover of Insulation Barrier

3-Phase Voltages - Overvoltages

Change of Capacitance

Number of Foils Change [%]Number of Foils Change [%]

40 2.560 1.7420

55 1.870 1.4550

30 3.342 2.4245

14 7.128 3.6123

Resin-ImpregnatedOil-ImpregnatedVoltage Level [kV]

Alarm Alarm LevelLevel


850 MVA / 420 kVGenerator Step-Up Unit


U [%]U [%]

Bushings – Change of Oil PressureLeakage on Phase U

W [%]W [%]

V [%]V [%]

HV-Bushing

Delta PressureDelta Pressure

Alarm Level


Active Part

Oil Temperature

Load Current

CurrentTransducer

Status of Cooling Unit

Load Current Oil Temperature Status of Cooling

Unit

Measuring Quantities Benefit Hot-Spot Temperature Overload Calculation Rate of Ageing


7.1. 17.1. 27.1. 6.2. 16.2. 26.2. 8.3.0

10

20

30

40

50

60

70

80 Töl RthN Rth (korrigiert)

Rth

[K/M

W],

Töl[°

C]

0

2

4

6

8

10

12

14

16

18

Anz

ahl L

üfte

r

Cooling Efficiency – Thermal Resistance [Rth]Detection of Pollution of Fans or Failure of Pumps


Cooling Unit

Alarm Level


Active Part

Buchholz Gas Sensor

Gas-in-Oil Sensor

Moisture of Oil Sensor

Gas-in-Oil Content Moisture of Oil / Paper Buchholz Gas Sensor

Measuring QuantitiesEarly Detection of Incipient Faults

Gas-in-Oil Sensor



Active Part – Gas-in-Oil Content Avoidance of Loss of Transformer

OLTC Oil-Metal Hot Spot

75 MVA Furnace Transformer

OLTC Oil-Metal Hot Spot

On-Line Oil Treatment

Alarm Level


Moisture of Oil [ppm]

Moisture of Paper [%]

Oil Temperature [°C]

Moisture of Oil / Paper ConditionTransformer Management

Active Part - Ageing

Active Part


Fingerprint –Power

Consumption

Motor Drive –Power Consumption

Tap Changer

Tap Position Power Consumption

of Motor Drive Acceleration Sensor

(optional) Moisture of Oil

(optional)

Measuring Quantities Benefit Sum of Switched

Load Current Contact Wear Assessment of Mechanical

Quality

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500450

500

550

600

650

700

750

Sta

rtin

g c

urr

en

t

Div

ert

er

switc

hin

g

Closing of contacts of tap selector

Opening of contacts of tap selector

Re

volu

tion

of

con

tact

s

Op

en

ing

of

sele

cto

r

Clo

sin

g o

f p

re-s

ele

cto

r

Op

en

ing

of

pre

-se

lect

orOp

en

ing

of

sele

cto

r

Act

ive

po

we

r [W

]

Time [ms]



Tap Changer MonitoringDetection of Defect Control CB in Motor Drive

Motor Drive


Bushings1. Operating voltages and overvoltages2. Change of capacitance, Leakage current *1

3. Load currents, overcurrents and short circuit currents4. Actual Power and load factor *1,3

5. Oil pressure and pressure difference

Active Part1. Oil temperature2. Gas-in-oil content3. Gas-in-oil gradient *7

4. Moisture in oil5. Moisture of paper *6,9

6. Gas quantity in the Buchholz relay7. Overload capacity *1,4,6,18,27,30

8. Emergency overloading time *1,4,6,18,27,30

9. Hot spot temperature *1,4,6,18,27,30

10. Bubbling temperature *6,9

11. Ageing rate *14

12. Lifetime consumption *16


Measuring / Analyse Quantities Tap Changer

1. On-load tap changer position2. Sum of switched load current *3,18

3. Power consumption of the motor drive4. Assessment of mechanical quality *18,20,24

5. Contact wear *19

6. Acceleration sensor7. Oil temperature8. Oil temperature difference OLTC / tank *6,24

9. Moisture in oil

Cooling Unit1. Operating condition of pumps and fans2. Oil temperature in/out of the cooler3. Cooler efficiency (Rth) *1,4,6,18,27,30

4. Ambient temperature5. Air temperature in/out of the cooler6. Thermal Model *1,4,6,18,27,30

7. Actual losses *1,4,6,18,27,30

Conservator1. Oil level2. Humidity of air inside conservator


Practical Experience


400 MVA Grid Coupling Transformer

Tap Changer

Active Part Cooling Unit

Bushings

MS 2000 Module


Transformers

FAX

Office

Field BusField Bus

MS 2000 ServerMS 2000 Server

Monitoring ModulesMonitoring Modules

IEC 60870-5-101IEC 60870-5-101Point to PointPoint to Point

Protection & Control

TCP/IP (Ethernet)TCP/IP (Ethernet) ModemModem

Substation

Architecture



Paket

Visualisation Tailor-made

Standard Standard Internet ExplorerInternet Explorer®®


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h41 s. Tenbohlen

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