Synchronous generator rotor position estimation from stator and rotor terminal currents and voltages

Abstract: This thesis presents an alternative method for measuring the rotor position of a synchronousgenerator, without the use of sensors to measure the rotor position. The method uses thecurrent and voltage measurements on the stator and rotor terminals from the protectionrelays. The rst step is to investigate how the rotor position can be estimated basedon the available measurement data. It was found out that the rotor position couldn'tbe estimated during dynamic state operation, when directly solving it from measurementdata. This is due to the presence of the eld and d-axis damper winding current dynamics,including the q-axis damper winding current. In order to achieve this, multiple stepsconsisting of dierent methods for estimating the rotor position were utilized. The rststep is to estimate the rotor position during steady state. The second step estimates therotor position iteratively based on initial values. This method is useful during a dynamicstate operation. The initial values are obtained from the rst step at the start of a dynamicstate operation. The nal step predicts the rotor position based on previous data. It isused during cases when the second step fails to estimate the rotor position accurately.Due to insucient data for estimating the rotor position during saturation, the eects ofsaturation for the simulated synchronous machine were not considered.