Microgrid Fault Analysis Method Based on Inverter-Type DG with Different Control

The microgrid contains inverter-type distributed generation (DG), and its fault characteristics are directly affected by the control strategies of DG. Therefore, the conventional fault analysis method of the distribution network is not suitable for the microgrid. Under fault conditions, the distributed generation has more complex fault characteristics due to its different control methods. Based on the output characteristic of inverter-type DG with constant power (PQ) control and V/F control, the constraint equation was obtained to construct an equivalent model of DG obstacle characteristic analysis. Then the equivalent models of microgrid under islanding operation and grid-connected operation modes are established, and the steady-state response is solved. Finally, the power grid simulation software DIgSILENT is applied to build a microgrid model containing inverter-type DGs which is constituted with PQ control and V/F control. By comparing with the conventional fault analysis method, the adaptability, effectiveness and accuracy of the proposed method are verified under different fault conditions as well as multiple control strategies, which provides an accurate criterion for microgrid protection method.