Using Smart Meter measurements to manage accuracy of current calculations in LV feeders

Abstract

Knowledge of currents in individual Low Voltage feeders of a secondary substation is interesting for distribution system operators for a variety of purposes. Deploying measurement devices at each feeder in each substation, however, can be costly. Due to the increasing deployment of Smart Meters, the knowledge about currents at each connected customer is in principle available. This paper proposes and evaluates an approach to determine the feeder currents taking into account the impact of measurement errors of Smart Meter measurements. The developed approach makes a rigorous derivation of confidence intervals for the calculated voltage and current values utilizing a subset of measured voltages and currents as input. The approach is applied to two realistic low voltage grids and the impact of measurement errors and missing smart meter measurements is quantitatively analyzed.

Extraction of CIM-Based Distribution Grid Topology Information for Observability

“…Given the expected data quality and measurement resolution in LV grids, transient calculations of the LV grid are out of scope and only steady-state grid calculation e.g. using Power-Flow calculations [11] complemented by pseudo-measurement generation [12] appears feasible; other examples of such grid model implementations may quantify the uncertainty of calculated electrical parameters [13].…”

On the Impact of Measurement Errors on Loss Calculations in Distribution Grids

“…In order to be eligible for the approaches in this paper, such grid model calculations must be able to not only provide the electrical variables in each grid point, but also the covariance matrix for these calculated values, see e.g. [14], [15].…”

“…We use the active power values derived from the energy measurements in one selected time interval in order to calculate voltages and currents everywhere in the grid by the grid model of [14]. The resulting voltages and currents are the assumed true values; under these assumed true voltage and currents, the resulting power loss obtained from Eq.…”

“…The ratio of the standard deviation of this simulated measurement error to the true value is called the relative measurement error and varied in these experiments. These erroneous measurements are then input the grid model framework of [14] to calculate all voltages and currents in the grid and to obtain the technical loss from these calculated values using Eq. (3).…”

Load approximation for uncertain topologies in the low-voltage grid

“…In [10], the researchers described an approach to address this problem by representing the measurement's confidence level with a complex normal distribution. None of the proposed solutions considers the uncertainty of the grid configuration (fuse states) from the best of our knowledge.…”