The Potential for a GIC-inclusive State Estimator

Power system state estimation is a key component of real-time monitoring, enabling extensive analysis and decision making for grid security and efficiency. One challenge that has seen recent interest involves the monitoring and mitigation of geomagnetically induced currents (GICs). These quasi-dc currents are the result of solar activity and can cause additional reactive power losses in transformers. The subsequent loss of reactive power support may result in voltage deviation at many buses. In a traditional state estimator, these voltage deviations may be masked by or attributed to incorrect estimations of generator reactive power output. Alternatively, the voltage state estimate may accumulate additional error, due to trying to match measurements to equations that do not represent the actual physical system and condition. This paper presents a case study that shows the need for state estimation models that consider GIC effects and analyzes the required increase in GIC-related measurements and models incurred therein.