Distributed generation micro-grid operation: Control, protection, and electricity market operation

The installation of Distributed Generation (DG) on the distribution system provides numerous benefits. Many countries are trying to meet the targets set to reduce greenhouse gas emissions and some DG provide an attractive option to accomplish this task. Besides that, DG can provide peak shaving, improved power quality and reliability, and increased efficiency. With the increasing penetration of DG, micro-grid or intentional islanding operation becomes an attractive and valuable option. Allowing micro-grid operation of DG provides additional technical and economical benefits. The micro-grid could meet the power quality and reliability requirements of the customers. In addition, micro-grids can provide other favorable tasks such as reactive and active power control, voltage sag mitigation, and system imbalance correction. Intentionally islanding of the DG could benefit various entities such as the DG owner, Distribution Network Operator (DNO), and customer.; Despite the numerous benefits micro-grids can bring to the power system, many challenges and technical issues constraint its operation. The DG interface control should be designed to maintain the voltage and frequency within acceptable levels during micro-grid operation. Short circuit currents vary during micro-grid operation, which could lead to misoperation of current sensing protective devices. The DG should be capable of supplying reactive power during micro-grid operation, which could have an impact on the effectiveness of currently proposed islanding detection protection. This thesis addresses the main challenges associated with micro-grid operation such as: Voltage/frequency control, micro-grid protection, and electricity market operation.; The thesis presents an adaptive DG interface control scheme for micro-grid operation. The proposed control scheme is based on integrating two control strategies, one for grid-connected operation and the other for islanded operation. The control scheme also includes an efficient islanding detection algorithm and a resynchronization control block to adaptively disconnect and connect the micro-grid from/to the grid system. The thesis also proposes a protection scheme based on current differential protective relays for protecting feeders on the micro-grid.; In addition, implementing intentional islanding of DG in a deregulated era will have an impact on the electricity market operation. The thesis proposes a new market operation strategy to analyze electricity market prices in the presence of micro-grids. This issue is considered in this thesis by solving the optimal power flow problem while accounting for the islanded operation.