Directional Detection for Over current Protection without Voltage Sensors in Systems with Distributed Generation

As the yearly electric energy demand grows, there is a significant increase in the penetration of distributed generation (DG). Since the conventional sources of energy such as coal, petroleum and natural gas etc. are fast disappearing, a study of distributed renewable generation systems becomes very important. Integration of a DG into an existing distribution system has many impacts on the system, with the power system protection being one of the major issues. Short circuit power of a distribution system changes when its state changes. It also changes when some of the generators in the distribution system are disconnected. This may result in elongation of fault clearing time and hence disconnection of equipment’s in the distribution system or unnecessary operation of protective devices. This thesis mainly deals with the protection algorithms that are to be met in order to avoid false \ud tripping problem because of bidirectional power flow