Partial discharge detection apparatus suitable for determining whether a partial discharge is of external or of internal origin, and a corresponding method
AssigneeALSTOM Technology Ltd
InventorsGilbert Luna, Sébastien Louise
Life of this patent
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Abstract
The invention relates to detection apparatus for detecting a partial discharge from live electrical apparatus, the detection apparatus comprising detection means (Pc) mounted on the live electrical apparatus (T) for the purpose of detecting the occurrence of at least one partial discharge, wherein said detection apparatus further comprises additional means (D1, D2, S) suitable for determining whether a detected partial discharge is internal or external relative to the live apparatus.
Claims9
Detection apparatus for detecting a partial discharge from a live electrical equipment tank (T), the detection apparatus comprising detection means (Pc, Pa, D1) placed in contact with the live electrical equipment (T) and suitable for detecting the occurrence of a partial discharge that is internal or external relative to the tank, said detection apparatus being characterized in that it comprises:
- a first ultra high frequency (“UHF”), measurement system (D1, A1) that includes a first UHF sensor (D1) inserted completely or partly into the tank and that delivers a UHF signal whenever a partial discharge occurs that is internal or external relative to the tank;
- a second ultra high frequency (“UHF”) measurement system (D2, A2) that is substantially identical to the first UHF measurement system and that includes a second UHF sensor (D2) placed at a distance from the tank and that delivers a UHF signal whenever a partial discharge occurs that is external relative to the tank;
- and
- an acquisition system (S) that comprises:
- acquisition means for acquiring, in a frequency band, background noise BF1 delivered by the first UHF measurement system and background noise BF2 delivered by the second UHF measurement system;
- search means for seeking steep fronts in a first UHF signal delivered by the first measurement system and in a second UHF signal delivered by the second measurement system, whenever any partial discharge is detected by the detection means;
- determination means for determining a maximum amplitude A(UHF1) of the first UHF signal and a maximum amplitude A(UHF2) of the second UHF signal if a steep front is detected in the first UHF signal and/or the second UHF signal;
- determination means (E3, E6, E7;
- E12, E15, E16) for determining, in the frequency band, a first signal-to-noise ratio R1 relating to the first UHF signal and a second signal-to-noise ratio R2 relating to the second UHF signal;
- comparator means (E8, E17) for comparing the ratios R1 and R2;
- and
- computation means (E9, E18) suitable for deciding whether a detected partial discharge is internal or external relative to the tank, as a function of the result delivered by the comparison step.
A detection method for detecting a partial discharge from a live electrical equipment tank, the method comprising a detection step (E4, E13) of detecting the occurrence of a partial discharge that is internal or external relative to the tank by means of detection means in contact with the electrical equipment, said method being characterized in that it comprises:
- an acquisition step of acquiring, in a frequency band, background noise BF1 delivered by a first ultra high frequency (“UHF”) measurement system that includes a first UHF sensor inserted completely or partly into the tank;
- an acquisition step of acquiring, in a frequency band, background noise BF2 delivered by a second UHF measurement system that is substantially identical to the first measurement system and that includes a sensor placed at a distance from the tank;
- a measurement step of measuring a UHF signal (E4, E13) using the first measurement system whenever a partial discharge occurs that is internal or external relative to the tank;
- a measurement step of measuring a UHF signal (E4, E13) using the second measurement system whenever a partial discharge occurs that is external relative to the tank;
- and
- an acquisition step (E5, E6, E7, E8, E9;
- E14, E15, E16, E17, E18) that comprises:
- a search step of seeking steep fronts (E5, E14) in the first UHF signal delivered by the first measurement system and in a second UHF signal delivered by the second measurement system, whenever any partial discharge is detected by the measuring means;
- a determination step of determining a maximum amplitude A(UHF1) of the first UHF signal and a maximum amplitude A(UHF2) of the second UHF signal if a steep front is detected in the first UHF signal and/or the second UHF signal;
- a determination step (E3, E6, E7;
- E12, E15, E16) of determining, in the frequency band, a first signal-to-noise ratio R1 relating to the first UHF signal and a second signal-to-noise ratio R2 relating to the second UHF signal;
- a comparison step (E8, E17) of comparing the ratios R1 and R2;
- and
- a computation step (E9, E18) suitable for deciding whether a detected partial discharge is internal or external relative to the tank, as a function of the result delivered by the comparison step.
Dependencies are inferred from the claim text.