Distance protection blocking and re‐opening scheme in multi‐machine power system oscillation scenes

摘要

In view of frequent multi-machine power system oscillations in power grid which may cause traditional oscillation blocking and re-opening schemes to be completely invalid, a distance protection oscillation blocking and re-opening scheme in multi-machine power system oscillation scenes is proposed in this paper. First, the ride-through trajectory of measured impedance in multi-machine power system oscillation cases and its effect on the operation characteristic of distance protection is analyzed, and the oscillation blocking scheme is formed by combining the operation status information of protection components on 2 line ends. And then, in the oscillation blocking duration, by calculating the estimated error of the dynamic phasor of measured current at the relaying point, the protection re-opening scheme for symmetrical fault during oscillation is established. Finally, simulation tests on PSCAD in 3-machine system and IEEE 39-bus system verify that the proposed scheme could reliably block the protection when oscillation occurs in multi-machine power system, and re-open the protection accurately and reliably when symmetrical fault occurs during oscillation.