Impact of Current and Power Measurements on Distribution System State Estimation Uncertainty

The effective management of future smart grids is strictly related to the accurate knowledge of the network operating conditions via distribution system state estimation (DSSE). To achieve this target, the measurement infrastructure of the distribution systems needs a substantial upgrade. However, obvious economic limitations prevent a massive deployment of measurement instruments on the field in short times. As a consequence, ad hoc meter placement techniques have to be applied to define location and type of a minimum set of measurements required to obtain the desired accuracy performance. This paper presents a mathematical analysis showing the impact of current and power measurements on the accuracy of DSSE results. The goal is to provide the analytical tools to identify the best placement for additional current or power measurements when applying an incremental deployment of meters in the distribution system. The analysis has a general validity but has also a clear impact on practical situations when the monitoring systems are upgraded starting from an existing infrastructure. Tests on a 95-bus sample grid are presented in order to validate the found mathematical results and to highlight the associated benefits in a meter placement perspective.