Hybrid simulation of distributed generation in grids

As many countries seek to use distributed energy more and move away from conventional centralized electricity delivery, the functioning of grids carrying distributed generation facilities becomes a relevant matter. Adoption of distributed generation fundamentally alters the properties of distribution grids, transforming them from passive transports and distributors into active distribution systems that have novel properties and dynamic characteristics, which inevitably causes the processes at major generation nodes and remote load nodes to affect each other in the context of reverse, rapidly changing power flows. Analysis presented herein shows that the mutual influence of distributed generation facilities and in-grid processes are ambiguous, and each case calls for analysis of its own, since, while being an advantage for the grid, distributed generation has negative impact, too, which pertains to the operating parameters of various DG types and units. How DG facilities and the grid affect each other can only be found by mathematical modeling; to maximize the accuracy, such modeling has to reproduce the most complete and detailed topology of grids carrying DG facilities; however, there are known limitations of software and hardware that prevent such modeling from returning accurate results. The authors hereof propose an alternative, hybrid approach to modeling electric systems (grid) that combines digital, analog, and physical-level modeling; the approach has been implemented as the All-Mode Real-Time Grid Simulation Complex. A specialized hybrid wind-farm processor has been designed and tested as a distributed generation unit of Tomsk Electric Grids.