Method for determining a switching time of an electrical switching device

Abstract

To devise a method for determining the switching moment of an electrical switching device with a first line part (2) arranged on which a driving voltage (4) is applied and a second line part (2) forming a resonant circuit after the switch-off process of the switching device Circuit breaker gaps (1) between line sections (3), with which the best possible switching moments of electrical switching devices can be determined to minimize transient overvoltages, it is recommended to: determine the establishment during the sampling period (t1) The time history of the voltage across the breaker gap (1), from which the resonance frequency of the resonant circuit is determined and from which the time window (Δt) is determined again, and after a defined time period (t2) has passed after the switch-off process The switching instant is asserted within this time window (Δt) from the zero-crossing determination of the envelope corresponding to the resonant frequency of the future history of the time-history calculation; ), from the determined time history the future time history of the voltage across the breaker gap and the resonant frequency of the resonant circuit, and from this in turn the time window (Δt) is determined and defined after the switch-off process The zero-crossing determination of the voltage across the breaker gap weighted by the drive voltage and the resonant circuit voltage after a time period (t2) of , is used to determine the switching instant within the determined time window (Δt).

Description

technical field [0001] The invention relates to a method for determining the switching moment of an electrical switching device with a circuit breaker gap arranged between a first line section to which an operating voltage is applied and a second part forming a resonant circuit after the switch-off process of the switching device. between the two line sections. Background technique [0002] Such a method is known, for example, from DE 10 2005 005 228 A1. Said document discloses a method for determining the switching times of an electrical switching device in the form of a gas-insulated switchgear, which can connect or disconnect a first line section with a generator for use in A second line part in the form of an overhead line supplies the first line part with a drive voltage. Such an overhead line forms a resonant circuit in a known manner after the opening of the electrical switching device and the separation of the first line part carrying the generator and the drive vo...

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Problems solved by technology

[0004] The method described in DE 10 2005 005 228 A1 is expensive because in it multiple successive zero crossings of the drive voltage and the resulting voltage have to be considered in a correlation and weighted using different criteria

Another method of pattern recognition does not always lead to the desired result, since the envelope of the voltage established across the breaker gap has a frequency which depends on the degree of compensation of the overhead line and thus on the resonant frequency of the resonant circuit, making it possible to determine Such a zero crossing of the envelope in the time window of is not within the time window when the degree of compensation is changed, and therefore the best possible switching moment cannot be determined

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