Method for monitoring and measuring an insulation resistance with interference-resistant measuring signal

摘要

A method for monitoring and measuring an insulation resistance in ungrounded and grounded power supply systems includes the method steps of generating a periodic measuring signal, coupling in the measuring signal between active conductors of the power supply system to be monitored and ground, and detecting and evaluating measured values of the measuring signal. In one embodiment of the invention, the generated measuring signal is formed as a multi-frequency signal by the superposition of a finite number of harmonic oscillations with at least three harmonics. Alternatively, the multi-frequency signal can also be realized by means of a targeted, portioned construction of the signal shape in the time domain on the basis of a binary sequence optimization or by generating the measuring signal by means of the time-division multiplexing method.

主权项

1. A method for monitoring and measuring an insulation resistance in ungrounded and grounded power supply systems, said method comprising the method steps of:
generating a periodic measuring signal with increased interference resistance against interference signals, wherein the measuring signal is constructed as a multi-frequency signal using a square pulse sequence, a square pulse that forms the sequence being divided into m portions of equal length, each of the m portions being binarily set, in an ordered manner, either in a unipolar manner to 0/1 or in a bipolar manner to −1/+1, Fourier coefficients for selected harmonics being calculated for each of the 2m possible square pulse sequences, the square pulse sequence being selected that fulfils the predefined requirements regarding a spectral composition of the square pulse sequence; coupling in the measuring signal between active conductors of a power supply system to be measured and ground; and detecting and evaluating measured values of the measuring signal by registering said measured values of the measured signal by a measuring device configured to monitor the insulation resistance of the power supply system.