Use this URL to cite or link to this record in EThOS:
Title: Improving fault location through interpole analysis of circuit breaker and automatic reclose scheme operation
Author: Ji, Liang
ISNI:       0000 0004 2744 5827
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2012
Availability of Full Text:
Access from EThOS:
Access from Institution:
This research concentrates on the development and evaluation of novel single ended impedance based fault location methods, which are easy and economical to implement in practice. The conventional single ended impedance based fault location methods normally suffer from negative effects associated with variability and inaccuracies in fault resistance, distance to fault and from the impact of variable remote end short circuit level. A novel concept of a single ended impedance based fault location method using analysis of 'interpole' states, which arise during the operation of the circuit breaker as the individual poles open sequentially, has been developed. The proposed fault location technique has been shown to have a very high theoretical accuracy by eliminating the aforementioned negative effects associated with conventional single ended impedance based methods. The thesis describes how the developed technique operates through comparing simulated voltage and currents during the interpole states with the actual measured voltage and currents, and searches for a match that may be indicative of fault location. When a match is found within a pre-specified tolerance error from analysis of the initial 'during fault' state, the ranges of corresponding possible fault locations, fault resistances and remote end short circuit levels used in the simulation are noted. The ranges of all possible values are subsequently reduced through analysis of the consecutive interpole stages as each pole of the circuit breaker opens sequentially to finally interrupt the flow of current in all three phases. The final, most accurate, fault location is obtained following on from analysis of the final state. Another single ended impedance based fault location method has been developed that extends the analysis to the operation of single/three phase auto-reclose schemes. Similarly with previous method, the second method also uses the analysis of different system states, which are arisen during the auto-reclose operation, and improves on the accuracy of the method that only analyses the single operation of the circuit breaker. The methods are demonstrated using EMTP/ATP simulation models for a variety of different cases and it is shown how high accuracy has been achieved, with improved performance when compared with conventional single ended impedance based method (Takagi method and network impedance method). Additionally, it is a potentially economic solution, as only local end data is required. The thesis concludes with an overview of ongoing and future work that has the intention of moving the work forward towards implementation within commercially available relay hardware.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available