Mitigating system's voltage instability through wide-area early warning signals and real-time HVDC control

Two sequential approaches to prevent voltage instability are proposed in this article. The first approach utilizes synchrophasors in order to establish when the system is leading to a voltage instability and also to trigger the operation of HVDCs to relieve the system's stress. The second approach is used to ensure that HVDCs will operate securely when their transfer is pushed towards the maximum transferable power level.