Location of a ground fault in an IT network
AssigneeSiemens Aktiengesellschaft
InventorBenno Weis
Life of this patent
Estimating the term…
Abstract
A method for locating a ground fault in an IT network which has a converter with a rectifier connected to a power transmission network, a DC link and an inverter connected to an electrical machine includes measuring a common-mode voltage property of the converter or of the power transmission network and comparing the common-mode voltage property with an output voltage property of an output voltage of the inverter. When the IT network experiences a ground fault, the comparison of the common-mode voltage property with the output voltage property is used to determine whether a machine area of the IT network connected downstream of the converter, which includes the electrical machine and a connecting line between the electrical machine and the converter, causes the ground fault.
Claims13
A method for locating a ground fault in an IT network comprising a converter having a rectifier connected at an input side to a power transmission network, and an inverter connected at an output side to a rotating electrical machine, and a DC link circuit connected between the rectifier and the inverter, said method comprising:
- measuring voltage pulses of a voltage between a DC link circuit potential of the DC link circuit and a ground potential or voltage pulses of a network voltage of the power transmission network and the ground potential;
- comparing the measured voltage pulses with switching actions of a phase of the inverter;
- specifying a count duration and a threshold value for a number of occurrences of the measured voltage pulses,
- measuring within the count duration an evaluation number of simultaneous voltage pulses and switching actions;
- and
- when the IT network experiences a ground fault and the evaluation number exceeds the threshold value for the number of occurrences, concluding that a machine area of the IT network connected downstream of the converter, which includes the electrical machine and a connecting line between the electrical machine and the converter, causes the ground fault.
A method for locating a ground fault in an IT network comprising a converter having a rectifier connected at an input side to a power transmission network, and an inverter connected at an output side to a rotating electrical machine, and a DC link circuit connected between the rectifier and the inverter, the method comprising:
- measuring a frequency spectrum of a network voltage of the power transmission network in relation to a ground potential;
- and
- when the IT network experiences a ground fault and the frequency spectrum of the network voltage has both a spectral component matching a basic output frequency of an output voltage of the inverter and a spectral component matching a switching frequency of the inverter, concluding that a machine area of the IT network connected downstream of the converter, which includes the electrical machine and a connecting line between the electrical machine and the converter, causes the ground fault.
Dependencies are inferred from the claim text.