A New Predictive Approach to Wide-Area Out-of-Step Protection

This paper presents a new approach to wide-area out-of-step (OOS) protection through predicting the power and rotor angle curves by the autoregressive moving-average (ARMA) method. To reduce the computation burden of ARMA, its parameters are estimated using an extended Kalman filter. The predictive feature of the proposed approach results in saving hundreds of milliseconds before the actual instability occurs, which can be served to activate appropriate countermeasures against wide-spread system instability. The OOS condition is detected using the extended equal area criterion developed for multimachine power systems, in which the single-machine infinite-bus model of the system is built using wide-area measurements. The proposed approach is adapted with the communication requirements of IEEE Std. C37.118, and thus, it can be used as a practical wide-area OOS protection scheme. The IEEE 39- and 118-bus systems are used to evaluate the efficiency of the proposed approach. The obtained results demonstrate the effectiveness of the proposed scheme in predicting OOS phenomena.