Sub-Cycle Fault Location in Electrical Systems:

IP and Current Status of Technology

Charles Kim [ckim@howard.edu]

Electrical and Computer EngineeringHoward University

May 28, 2013 1

Initial Development•2008 Idea (Algorithm) Formation

•Target faults: Sub-cycle Self-clearing faults (as opposed to steady-state permanent faults the conventional fault location methods were developed) in over-head and underground cable lines•Uniqueness/Novelty 1: Inverse time-domain approach (as opposed to the conventional methods’ frequency (and complex quantity) domain approach.•Uniqueness/Novelty 2: Usage of Net Fault quantities (voltage and current) based on the superposition theorem and voltage injection approach

2

Preliminary Evaluation and Added Features•2009 Testing with Real Data

•Testing with SDG&E measured data•All types of sub-cycle faults

•Single Line to Ground•Double Line (to Ground)•Three Line (to Ground)

•Justification of further study and more testing•2010 New Ideas Added

•Direction of location as referenced to the location of the fault location system

•Upstream•Downstream

3

1st Patent Filing•August 2010 Invention Disclosure File to Howard University IP Office•October 2010 Patent Filed

•“Apparatus and Method for Fault Detection and Location Determination” 12/902819•Published on 04/12/2013•Contents:

•Algorithm for Fault Location•Directionality: up-stream and down-stream

4

2nd Patent Filing• Feb 2012 Invention Disclosure File to Howard University IP Office•May 2012 Patent Filed

•“Apparatus and Method for Fault Detection and Location Determination” •Not Published Yet•Contents:

•Algorithm for Fault Location with emphasis on Cables•Accommodation of coupling effects in 3-phase systems

5

Further Development•Summer 2012 Further Testing and Verification with SDG&E Real Data•Fall 2012- Spring 2013 Accuracy Improvement

•Inclusion of Resistance in the Algorithm Formula•Application of Least-Square method to calculate the fault location (by inductance, which is the usual parameter for fault location in the patents filed) and the resistance•Evaluation with more practical data

•May 2013 SDG&E and Howard University Patent Co-Ownership and Collaboration Agreement 6