High Impedance Fault Detection System

A High Impedance fault (HIF) occurs when an energized primary conductor comes in contact with a semi-insulated object such as tree, structure or equipment, or falls to the ground. HIFs on distribution systems are extremely difficult to detect because they do not generate enough fault current to be detectable by conventional overcurrent relays or fuses. HIFs do not pose imminent danger to power system equipment because they have very little fault current. However, they are a considerable threat to public safety. A common detection algorithm applied to HIFs devices is to observe the fault currents third harmonic and the change in angle, but this algorithm is difficult to differentiate between HIFs and low nonlinear loads. A new detection algorithm based on impedance measurement has been put forward by Dr. Jose Martis research group in University of British Columbia (UBC). We are going to apply this new method in HIFs detection to differentiate between HIFs and the non-fault state of an open circuit or normal load conditions. We will program this new algorithm in BC Hydros distribution system protective devices with sufficient embedded computing capabilities, and verify this new detection algorithm. TO BE CONT’D

Faculty Supervisor:

Jose Marti

Student:

Zhibang Liang

Partner:

BC Hydro

Discipline:

Engineering - computer / electrical

Sector:

Manufacturing

University:

University of British Columbia