High impedance fault detection

A system for detecting a high impedance fault in an electrical power system having an alternating current flowing therethrough comprising:

• an electrical power supply;
• one or more interconnected electrical power conductors;
• and
• a composite high impedance fault detection system connected to said one or more electrical power conductors for detecting said high impedance fault, said composite high impedance fault detection system comprising:
• a plurality of high impedance fault detection systems operable to respectively make a plurality of independent determinations whether said high impedance fault has occurred and to respectively generate outputs representative of said independent determinations;
• and
• decision means connected to said high impedance fault detection systems for determining whether said high impedance fault has occurred, said decision means determining that said high impedance fault has occurred if any two or more of said outputs indicate that said high impedance fault has occurred.

An apparatus for detecting a high impedance fault in electrical power lines comprising:

• a wavelet based system for detecting said high impedance fault condition in said electrical power lines and having a first logical output;
• a higher order statistics based system for detecting said high impedance fault condition in said electrical power lines and having a second logical output;
• and
• a neural network based system for detecting said high impedance fault condition in said electrical power lines and having a third logical output,
• a decision logic for determining whether said high impedance fault has occurred, wherein said decision logic determines that said high impedance fault has occurred if any two of said first logical output, said second logical output, and said third logical output indicate that said high impedance fault has occurred.

An apparatus for detecting a high impedance fault in electrical power lines comprising:

• a composite high impedance fault detection system for connection to said electrical power lines for detecting said high impedance fault, said composite high impedance fault detection system comprising:
• a plurality of high impedance fault detection systems operable to respectively make a plurality of independent determinations whether said high impedance fault has occurred and to respectively generate outputs representative of said independent determinations:
• and
• decision means connected to said high impedance fault detection systems for determining whether said high impedance fault has occurred, said decision means determining that said high impedance fault has occurred if any two or more of said outputs indicate that said high impedance fault has occurred.