Intrusion detection system for electric fences

A low voltage intrusion detection system for an electric fence, said fence having a wire with a feed terminal and a return terminal for connection to said energizer, said low voltage intrusion detection system comprising:

• a current source for supplying a low current to the feed terminal;
• a filter for receiving a return voltage signal at the return terminal and for supplying a filtered voltage signal;
• a voltage comparator for receiving the filtered voltage signal and for providing an output signal if the filtered voltage signal exceeds a predetermined threshold voltage;
• and
• a controller for receiving the output signal from the voltage comparator, for monitoring the voltage at the feed terminal, and for determining that a short circuit is present on the wire of the fence if the voltage at the feed terminal is low.

A method of energizing an electric fence having a wire with a feed terminal and a return terminal for connection to an energizer, said method comprising the steps of:

• generating high voltage pulses at the feed terminal with a high voltage pulse generator;
• providing a low voltage signal at the feed terminal from a low voltage circuit;
• and
• monitoring any changes in the low voltage signal at the return terminal, and the voltage at the feed terminal, to determine if the wire of the fence has been touched, or if the wire of the fence encounters a short circuit or an open circuit.

A method of detecting intrusion to an electric fence, said method comprising the steps of:

• supplying a low current from a current source to a feed terminal for a wire in the fence;
• receiving a return voltage signal at a return terminal of the wire;
• filtering the return voltage signal to supply a filtered voltage signal;
• comparing the filtered voltage signal to a predetermined voltage threshold;
• providing an compared output signal if the filtered voltage signal exceeds the predetermined threshold voltage;
• monitoring the voltage at the feed terminal;
• and
• determining that a short circuit is present on the wire of the fence if the voltage at the feed terminal is low.