Insulation fault detection device, electrical power supply system, and a method for detecting an insulation fault

An insulation fault detection device for detecting insulations faults in an electrical power supply system of an electrically or hybrid driven aircraft, wherein the electrical power supply system being configured with a DC section and an AC section, wherein the insulation fault detection device includes:

• an input terminal configured to receive a measurement signal, which is a voltage measurement signal, from a voltage sensor, preferably external to the insulation fault detection device;
• an output terminal arranged to provide a signal for indicating an insulation fault;
• characterized in that;
• and
• a processor coupled to the input and output terminal, and wherein the processor is configured to:
• detect frequency and/or a slope of an AC voltage component comprised in the measurement signal of the measurement signal;
• and
• set the signal at the output terminal depending on the detected frequency and/or a slope of an AC component comprised in the measurement signal, wherein the AC voltage component comprised in the voltage measurement signal is a signal having a predefined shape, and wherein the slope corresponds to an edge of the signal and wherein the signal at the output terminal is set upon the detection of the edge of the signal.

An electrical power supply system for an electrically or hybrid driven aircraft comprising:

• an insulation fault detection device;
• a voltage sensor;
• an electrical source configured with a first and a second output for supplying a DC voltage, the DC voltage having a first and a second DC potential;
• a load configured with an input end and an output end, wherein the input end is connected to the first and the second output of the electrical source, and the output end is connected to an AC consumer;
• an electric connection permanently connecting one of the DC potentials to a reference potential of the aircraft, and wherein the electrical source and the load are configured to insulate the DC potentials from each other, wherein
• the voltage sensor is electrically connected to one of the DC potentials and the reference potential for determining a potential difference between one of the DC potentials and the reference potential.