Study on Three-phase Stability Simulation Model of Distributed Generation System for Multi Energy Utilization

There are many different kinds of energy in future multi-energy system, such as electric, gas, heat and hydrogen. Distributed generation system integrated as microgrid is one of the most important use form of multi-energy system for customer-side. Considering typical grid-connected distributed generation system and three phase unbalanced feature of low-voltage micro-grid, three-phase stability simulation technique is a very important analysis tool for system-level energy optimization management, design of control strategy, structure stability and so on. A unified interface model of grid-connected system for synchronous generator and inverter is discussed in this paper. The unified model is given in three conventional dq coordinates and described by Norton model which is the parallel connection of injection current source and constant admittance matrix. Based on the characteristics of the unified interface model and detailed dynamics of distributed sources, an alternative implicit trapezoidal integration algorithm is developed for the stability simulation of distributed generation system. The significance of the proposed modeling method is validated by test example simulation results.