High Voltage Substation Surveillance utilizing Radio Frequency Interference Measurement

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High Voltage Substation Surveillance utilizing Radio Frequency Interference Measurement

Detecting halfway release (roundabout estimation) RFI Electric Thermal Partial release Pressure/Acoustic Light Acoustic Chemical

RF beat from a PD related source Partial release beat RFI outflow FFT recurrence range of PD heartbeat

CASE Inkoo 110 kV CT 5 Selective testing focusing on principally old 110 kV CTs found a unit with a high C2 control consider ~0,95 %. (Strömberg KOTU F41 sort, manuf. 1972) A DGA follow up demonstrated impressive gassing TCG 18 000 ppm (H2 12037 ppm, CH4 4839 ppm, C2H6 1058 ppm) analyzed as D1 low vitality release Suitable test case...? Doble were requested a PDS100 daze test.

6 Pvm Esityksen nimi/Tekijä

Baseline estimation 7 Baseline measured outside the wall Low backround commotion levels Discharges in oil will have higher recurrence content GSM Typical recurrence zone for air releases <150 MHz

8 No signs Baseline Suspected thing Measuring focuses on the administration street amongst CBs and CTs

Measurements 9 The broken unit was succesfully found A little PD flag was enrolled ~15dB above pattern Attennuation of high frequencies is helpful in the area procedure The 110 kV CT was supplanted - no flag after substitution (after one month)

HV Lab testing of the CT 10 PD Ignites at 74 kV stage to-earth voltage (128 kV primary voltage), evident charge was 50-60 pC Extinguishing voltage is impressively lower around 45 kV (77 kV fundamental voltage) At 1,2 x Um/(85 kV) release level was 150 pC Internal weight 0,75 bar (0,6 considered ordinary) Tandelta somewhat expanding as a component of voltage up to 70 kV, 0,43...0,59 % Tandelta increments quickly when PD touches off at 74 kV being 1,76 % at 123 kV CT passed the 0,75 x 230 kV, 50 Hz 1 min overvoltage test

Advantages of RFI Non-obtrusive, no requirement for physical or electrical association. Does not require gear under test to be removed from administration. May be embraced for first-line substation reconnaissance. Rate and seriousness of release can be observed and inclined.

Thanks for your kind consideration! Questions? Contact: Alan Nesbitt Brian Stewart Glasgow Caledonian University Scotland, UK ane2@gcal.ac.uk Contact: Micael Hellquist Hans Ove Kristiansen Doble TransiNor AS Norway info@doble.no