Date of Award

May 2014

Degree Type

Thesis

Degree Name

Master of Science

Department

Engineering

First Advisor

Adel Nasiri

Committee Members

David Yu, Chris Yuan

Keywords

Distributed Generation, Fault Analysis, IEEE 34 Bus, Load Flow, Protection

Abstract

The existing power system was not designed with distribution generation (DG) in mind. As DG penetration is being considered by many distribution utilities, there is a rising need to address many incompatibility issues which puts a big emphasis on the need to review and implement suitable protection scheme. The usual practice for existing distribution feeders is the Overcurrent scheme which includes coordination between fuses and reclosers. But when DG is added to the distribution feeder, the configuration is no more radial as there is contribution of fault currents from the DG's and if the existing protection scheme is applied then this could lead to various issues like fuse misoperation or nuisance tripping considering temporary and permanent fault conditions.

This thesis presents a study on the modeling of existing IEEE 34 radial distribution feeder and scaling of the system from 24.9kV to 12.47kV keeping in mind the existing conditions and also proposes a protection scheme with and without the addition of DG's to the feeder nodes. The protection scheme involves providing appropriate relaying with suitable fuse selection and Current transformer settings. Considerations for proper transformer grounding and capacitor bank fusing protection is also simulated and reviewed. When DG's added, the results show increase in fault contribution and hence causing misoperations which needs to avoided. Relaying considerations are also provided when an islanded mode occurs. The entire analysis has been simulated by a combination of various tools like Aspen One liner, CYMDist and Wavewin with occasional simulations and calculations performed in MATLAB environment.

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