Utility-based operation management for low voltage distribution grids using online optimization

Abstract

We present an operation management controller for low voltage (LV) grids that coordinates a multitude of distributed energy resources (DER) in real time to maximize the utilization of renewable energy production. It utilizes an LTE radio network that connects the DERs to the distribution system operator. In our approach, utility functions are assigned to the DERs, and the utility maximization is formulated as an optimization problem. The optimization problem is solved by an iterative algorithm that performs incremental updates of the DER power set values to achieve the optimum. In order to take the state of the grid in the optimization process into account, the state of the grid is estimated. During the simulation of a use case, we demonstrate the applicability and identify the benefits of our approach compared to an established optimal power flow (OPF) method. Particular emphasis is put on evaluating the communication delay and feasibility of the required communication network, as the iterative approach leads to a high communication load.

Distributed utility‐based real‐time power flow optimization in ICT‐enabled low voltage distribution grids

“…Further research need concerns the joint in-depth modelling and testing of OFO based OPF and communication network behavior, which is especially relevant in distributed approaches with high communication demand, and the further development of the utility-based approach. This work addresses this research need by building on [17]. First, we extend the optimization problem formulation and the solution algorithm.…”

“…The utility approach differs from classical OPF approaches that usually aim at a minimization of generation costs. As proposed in [17], each DER's utility function is composed of two parts: a basic utility function Φ base and a priority factor w, resulting in the utility…”

“…It should be noted that the ability of the online utility maximization to adhere to keep voltages and currents within their defined limits defined by ( 14) and ( 15) has been shown in [17] and is therefore not focussed here. Instead, we emphasize the effects of the newly introduced time-varying priorities, the substation utility functions and of communication network imperfections.…”

“…It combines a branch-current based SE method and an OFO algorithm. Instead of minimizing a generic cost function as in [7,14], a utility measure is introduced in [17] that should be maximized. The utility measure is inspired by optimization approaches from communication networks [18,19], and in this context it is intended to quantify a DER's need for power consumption or generation.…”

“…In our previous work [17], we propose a real‐time method for the coordinated control of DERs within a LV grid. It combines a branch‐current based SE method and an OFO algorithm.…”