Identifying Generators at Risk of SSR in Meshed Compensated AC/DC Power Networks

The paper presents a methodology to identify generators at risk of subsynchronous resonance (SSR) in meshed AC/DC networks. Two risk indices are developed to rank generators based on the level of exposure to SSR. One of them measures the severity of subsynchronous torsional interactions, and the other indicates the gravity of transient torque problem. It is shown that proposed indices can be used to identify generators in the network that are at the risk of experiencing high mechanical torques due to SSR and to rank them based on severity of potential exposure to SSR. The methodology is demonstrated on meshed 16-machine, 68-bus IEEE test network with different series compensation levels of AC lines, asymmetrical compensation and voltage source converter (VSC) based HVDC lines. Finally, electromagnetic transient simulations are used to verify the ranking of generators obtained using developed indices.