Power System Dynamic State Tracking Under Normal and Disturbance Conditions

Monitoring and control of power system dynamics in the control room has become an important issue for power systems dominated by inverter interfaced resources characterized by faster dynamics. For these systems it is also important to track the dynamics during disturbances and faults. Traditional state estimators are not able to track the dynamics and especially during disturbance conditions, including fault conditions. This paper describes implementation and field experience of a Distributed Quasi-dynamic State Estimator (DQSE) which tracks the system dynamic state during normal as well as disturbance conditions, including during fault conditions. DQSE tracks the dynamic state of the system at a rate of once per cycle. At this rate, the dynamics of the power system are well captured; note that electromechanical dynamics are relatively slow and are well captured at this rate; dynamics from operation of inverters are dominated by the controllers of the inverters which are faster than electromechanical transients and they are also well captured by a rate of once per cycle.