Investigation of voltage quality and distribution capacity issues on long rural distribution feeders and SWER systems

Single Wire Earth Return (SWER) electric distribution feeders are used extensively in remote parts of Queensland and other states, as an economic means to deliver electrical energy to small customer loads, scattered sparsely over vast areas. These SWER systems are normally supplied from very long three-phase distribution feeders. Due to recent strong load growth, voltage quality issues have arisen in these systems. The main SWER feeder problem is poor voltage regulation caused by increasing loads. Three-phase feeder problems include voltage unbalance and phase angle unbalance caused by increasing loads and uneven load distribution. High system network losses are also experienced, as a result of increasing loads. There are several available methods to combat these issues, however, most have not been applied to rural distribution previously. Developing simple, economic solutions to these problems is likely to dramatically improve customer power quality, resulting in reduced customer complaints, whilst improving distribution capacity and reducing losses. The emphasis of this research project is the power system modelling required to develop detailed equipment models that can be used to assess potential solutions identified in the literature. Ergon Energy Corporation in Central Queensland is supporting the project with field data and other information. This thesis has developed detailed models to study voltage regulation of SWER feeders and capacity enhancement of three-phase feeders.