ABSTRACT
As discussed earlier, grid-tied microgrids can operate in both gridconnected (grid-tied) or islanded modes.1 Microgrids are usually connected to the low-voltage side of the power distribution system of the main power grid. When islanded, the microgrid acts as an autonomous power system, in which the frequency and voltage has to be tightly controlled, while the system is held stable and reliable for load variations under different operating conditions. Similarly, when the
8.1 Screening Studies 208 8.2 Microgrid Elements 213
8.2.1 Point of Common Coupling 213 8.2.2 Microgrid Loads 214 8.2.3 Power Plants 214 8.2.4 Islanding Breaker 217 8.2.5 Synchronizing Mechanism 219
8.3 Microgrid Impacts 219 8.3.1 Voltage Regulation 221 8.3.2 Direct Current Injection 222 8.3.3 Power Factor 223 8.3.4 Protection 223 8.3.5 Overvoltage Switching Transient 225 8.3.6 Voltage and Frequency Stability 226 8.3.7 Antiislanding Protection 226
8.4 OASIS Case Study 226 8.4.1 General Requirements 227 8.4.2 Protection 228 8.4.3 Control and Telecommunications Requirements 230 8.4.4 Project Interconnection Requirements 230
References 231
microgrid is connected to the grid, it should not adversely impact the operation of the main power system and its interconnected distribution system.
