Stability Enhancement of Renewable Energy Bases Using High-inertia Synchronous Condensers

The transient instability of renewable energy power plants often plays a decisive role in the evolution process of power outages, due to the low tolerance for faults. Installation of small capacity synchronous condensers within renewable power plants has become one popular solution, since they can provide instantaneous reactive power to mitigate the risk of voltage instability. Moreover, the risk of frequency instability is becoming prominent, constrained by the reduction of system inertia. Optimizing the stability support capability by increasing the inertia of the synchronous condenser is a joint attempt by both academia and industry. This paper proposes a method for analyzing the supporting effect of high-inertia synchronous condenser (HISC) based on short-circuit ratio (SCR) and inertia. Firstly, the principle and operating characteristics of HISC are depicted in details. Secondly, the effects of HISCs on stability enhancement of renewable energy bases are derived and analyzed. Finally, the proposed method is verified under a condition where the penetration rate of renewable energy exceeds 35% and the fault duration lasts from 0.2s to 0.625s. The simulation results show that the HISCs can provide high-reliability stability supports for renewable energy bases, and are the basic guarantee for the new type power systems.