Mitigation of Subsynchronous Interactions in Hybrid AC/DC Grid With Renewable Energy Using Faster-Than-Real-Time Dynamic Simulation

摘要

Transmission line capacity enhancement by series compensation is commonly used in power systems, which consequently faces potential subsynchronous interaction (SSI). In this work, faster-than-real-time (FTRT) simulation based on the field-programmable gate arrays is proposed to mitigate the disastrous SSI in a hybrid AC/DC grid integrated with wind farms. Dynamic simulation is applied to the AC system to gain a high speedup over real-time, and a detailed multi-mass model is specifically introduced to the synchronous generator to show the electrical-mechanical interaction. Meanwhile, the DC grid undergoes electromagnetic transient simulation to reflect the impact of power converters' control on the overall grid, and consequently, the EMT-dynamic co-simulation running concurrently due to FPGA's hardware parallelism is formed. As the two simulations are inherently distinct, a power-voltage interface is adopted to separate them which enables their coexistence in one program. It shows that following the detection of a contingency, the FTRT hardware platform can generate an optimum solution with precisely quantified power flow changes in advance to keep the hybrid AC/DC grid stable. The FTRT efficacy is proven by a number of cases where the accuracy is validated by offline simulation tool Matlab/Simulink.