Monitoring method and device for input loss coefficient of capacitor

摘要

Method for monitoring capacitor bushings for an AC network, wherein - the AC network has a first, a second and a third phase (A, B, C) and a capacitor bushing (2a, 2b, 2c) is assigned to each phase; - at a predetermined first time (t1) for each of these phases • a corresponding first reference voltage phasor (Ra(t1), Rb(t1), Rc(t1)) is determined for a first reference voltage; • a foil voltage is captured and a corresponding first foil voltage phasor (Va(t1), Vb(t1), Vc(t1)) is determined; - at a predetermined second time (t2) which is after the first time, for each of these phases • a corresponding second reference voltage phasor (Ra(t2),Rb(t2), Rc(t2)) is determined for a second reference voltage; • the foil voltage is captured and a corresponding second foil voltage phasor (Va(t2), Vb(t2), Vc(t2)) is determined; - for each of these capacitor bushings • a loss factor change (ΔDa, ΔDb, ΔDc) is calculated on the basis of the respective first and second reference voltage phasors and foil voltage phasors and on the basis of the first and second reference voltage phasors and foil voltage phasors of the adjacent capacitor bushing in each case; • the loss factor change is compared with a tolerance value (DA, DB, DC); - a monitoring signal is generated on the basis of the results of these loss factor comparisons.