MScEng / Thesis (MScEng (Electrical and Electronic Engineering))--Univerity of Stellenbosch, 2009. / ENGLISH ABSTRACT: As the number of distributed generation units connected to a distribution network increase, the possibility of island formation increases. An island is formed when distributed generation units continue to energize local loads within a section of the grid, which has been disconnected from the main distribution network. These islands pose significant danger to maintenance personnel as well as to members of the public. In this study, an investigation is done into various anti-islanding methods. The modes of operation of these methods are discussed, as well as their strengths and weaknesses. The slip-mode frequency shift method and the Sandia voltage shift method, in combination with over/under voltage and frequency protection, are simulated and tested to confirm their functionality. The results obtained show that it is possible to prevent distributed generation units from energizing local loads when the grid is disconnected. / AFRIKAANSE OPSOMMING: Die moontlike toekomstige toename in die aantal verspreide generasie eenhede gekoppel aan die verspreidings netwerk, verhoog die moontlikheid van eiland vorming. ‘n Eiland word gevorm wanneer verspreide generasie eenhede energie aan lokale laste voorsien nadat die netwerk ontkoppel is. Dit hou groot gevaar in vir onderhouds personeel asook vir die publiek. In die tesis word ‘n studie gedoen oor die verskillende metodes om die vorming van ongewensde eilande te voorkom. Die glipmode-frekwensieskuif metode en die Sandia spanningskuif metode word gekombineer met die oor/onder spanning en frekwensie beskerming metodes. Die kombinasie van metodes word dan gesimuleer en eksperimenteel getoets. Die verkrygde resultate toon dat dit moontlik is om die vorming van ongewensde eilande effektief te voorkom.