Greedy Placement of Measurement Devices on Distribution Grids based on Enhanced Distflow State Estimation

TL;DR

This paper presents a practical method for optimally placing measurement devices in distribution grids, using an enhanced state-estimation algorithm based on the Distflow model to improve observability in low voltage networks.

Contribution

It introduces a novel placement scheme combined with an improved Distflow-based state estimation that accounts for shunt elements, optimizing measurement device placement.

Findings

Validated on a real-world grid with 85 nodes from Geneva, Switzerland.

Achieved minimal device placement while satisfying observability accuracy requirements.

Demonstrated effectiveness of the approach in practical distribution network scenarios.

Abstract

The needs for improving observability of medium and low voltage distribution networks has been significantly increased, in recent year. In this paper, we focus on practical approaches for placement of affordable Measurement Devices (MDs), which are providing three phases voltage, current, and power measurements with certain level of precision. The placement procedure is composed of a state-estimation algorithm and of a greedy placement scheme. The proposed state-estimation algorithm is based on the Distflow model, enhanced to consider the shunt elements (e.g., cable capacitances) of the network, which are not negligible in low voltage networks with underground cables. The greedy placement scheme is formulated such that it finds the location of minimum required number of MDs while certain grid observability limits are satisfied. These limits are defined as the accuracy of state-estimation results in terms of voltage magnitudes and line currents over all nodes and lines, respectively. The effectiveness of the proposed placement procedure has been validated on a realistic test grid of 10 medium voltage nodes and 75 low voltage nodes, whose topology and parameters were made available from the Distribution System Operator (DSO) of the city of Geneva, Switzerland.