quality control stages of mv gis and pd - measurement

Prof. Dr.-Ing.habil. Rainer Haller Power & Environmental Engineering ZCU Pilsen/ Cz

Diagnostica ´07

Partial Discharge Diagnostic of Medium Voltage Switchgear under

Operating Conditions using a special PD- Probe


Diagnostica ´07

Quality Control Stages of MV GIS and PD - Measurement

demands

high sensitivity ( ~ pC)

failure identification

failure location

pd

- m

eas

ure

me

nt

pd data base

(pc- based system)

development

manufacturing

assembling

transport/ on site assembling

operation

PRPD pattern


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Phase- Resolved-PD- (PRPD) Pattern

measured parameter: q (U, φ, t, ….)

acc. to CIGRE- format)


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PRPD- Pattern of a defect part

PD pattern of a separation between the insert and

the cast resin at the grounded side of a 36-kV-spacer


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special problems for on- site- diagnosis demand for no- switching- off of operational voltage,

but compatibility to pd- test procedures during manu-

facturing process

measuring of PRPD- pattern for comparison with

reference pd- data- base seems to be necessary

calibrating procedures are necessary

(unconventional measuring methods like acoustical/

optical methods are not sufficient)

coupling elements are necessary


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Typical measurement conditions for on- site- testing

pd- spectra with disturbancespd´s superimposed with large distur-

bances caused by near located SFC


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special problems for on- site- diagnosis

requirement of high measuring sensitivity

special requirements/ procedures for suppressing

of noise/ disturbances


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pd- on- site measurement by electromagnetic

field coupling


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transfer characteristic of pd- probes (UHF- measurement)

[acc. to IEC 60270]

UHF- Measurement


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transfer characteristic with and without pd- probe


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diagnostic- object: medium voltage switchgear

h.v. joints

user- table

capacitive sensor

36kV GIS- substation modules


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measuring sensitivity with capacitive sensor coupling

equivalent test circuit

q- sensitivity is non sufficient


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medium voltage switchgear with additional cable- parts

h.v. joints

user- table

capacitive sensor

cable- parts


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transfer characteristic with additional cable- parts

test circuit

transfer characteristic


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pd calibration with and without connected power cable

0100200300400500600700800900

10001100

0 100 200 300 400 500 600 700 800 900 1000 1100

eingespeiste Ladung / pC

gem

esse

ne

Lad

un

g /

pC

without power cable

with power cable-classical pd- meas. system

-- pd- probe


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diagnosis results

capacitive sensor

pd probe and measuring impedance

defect spacer


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conclusions pd measurements are up to now an essen-

tial tool for quality testing of electrical

insulation even for on- site diagnosis

demanding for no- switching- off of

operation voltage during the testing leads

to non classical measurement methods

(UHF- measurement by special pd- probes)


Diagnostica ´07

if into the switchgear a capacitive sensor is available, so by using a special pd- probe sensitive PD- on site- tests can be provided

the measuring sensitivity can be increased significantly by using of appropriate resonance elements like cabel- parts

this testing arrangement can be used in principle even for similar configurations.


Diagnostica ´07

Thank you --dekuji za pozornost

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quality control stages of mv gis and pd - measurement

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