There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Use of model predictive control and weather forecasts for energy efficient building climate control

A communication infrastructure is an essential part to the success of the emerging smart grid. A scalable and pervasive communication infrastructure is crucial in both construction and operation of a smart grid. In this paper, we present the background and motivation of communication infrastructures in smart grid systems. We also summarize major requirements that smart grid communications must meet. From the experience of several industrial trials on smart grid with communication infrastructures, we expect that the traditional carbon fuel based power plants can cooperate with emerging distributed renewable energy such as wind, solar, etc, to reduce the carbon fuel consumption and consequent green house gas such as carbon dioxide emission. The consumers can minimize their expense on energy by adjusting their intelligent home appliance operations to avoid the peak hours and utilize the renewable energy instead. We further explore the challenges for a communication infrastructure as the part of a complex smart grid system. Since a smart grid system might have over millions of consumers and devices, the demand of its reliability and security is extremely critical. Through a communication infrastructure, a smart grid can improve power reliability and quality to eliminate electricity blackout. Security is a challenging issue since the on-going smart grid systems facing increasing vulnerabilities as more and more automation, remote monitoring/controlling and supervision entities are interconnected.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1315&context=electricalengineeringfacpub

A Survey on Smart Grid CommunicationInfrastructures: Motivations, Requirements andChallenges

Theory and applications of HVAC control systems – A review of model predictive control (MPC)

The significant benefits associated with microgrids have led to vast efforts to expand their penetration in electric power systems. Although their deployment is rapidly growing, there are still many challenges to efficiently design, control, and operate microgrids when connected to the grid, and also when in islanded mode, where extensive research activities are underway to tackle these issues. It is necessary to have an across-the-board view of the microgrid integration in power systems. This paper presents a review of issues concerning microgrids and provides an account of research in areas related to microgrids, including distributed generation, microgrid value propositions, applications of power electronics, economic issues, microgrid operation and control, microgrid clusters, and protection and communications issues.

State of the Art in Research on Microgrids: A Review

—This paper considers Automatic Generation Control (AGC) enhancement by exploring the synergy between conventional generators and an aggregated Battery Energy Storage System (BESS). In practice, it has been observed that BESSs sometimes inefﬁciently contribute to the minimization of Area Control Error (ACE). This phenomenon is open to several interpretations. On the one hand, cost-effective aggregation of BESSs has not been well-established. On the other hand, BESSs could be driven into an inefﬁcient operation due to miscalculated ACE. Moreover, some BESSs may have to operate in the opposite direction than desired to maintain energy neutrality. Therefore, this paper presents a novel scheme termed Optimization-based Ramping Reserve Allocation (ORRA) for BESS aggregation, addressing the three issues simultaneously. The underlying methodology is to formulate the BESS aggregation problem as an distributed online optimization problem and solve it in real-time, where corrected ACE is leveraged to quantify the instantaneous ramping requirements. Another distinctive feature of ORRA lies in its ability to immediately deploy and smoothly un-deploy the aggregated BESS with respect to a frequency event, thereby contributing to energy-neutral operation. The optimization algorithm is fully distributed and can guarantee fair and near-optimal allocation in real-time. Simulations on a modiﬁed IEEE 14-bus system are performed to illustrate the effectiveness of ORRA.

Optimization-Based Ramping Reserve Allocation of Aggregated BESS for AGC Enhancement

Optimal Frequency Restoration of Inverter-Interfaced Microgrids via Distributed Energy Management

Nowadays, power grids are facing reduced total system inertia as traditional generators are phased out in favor of renewable energy sources. This issue is expected to deepen with the increasing penetration of electric vehicles (EVs). The influence of a single EV on power networks is low; nevertheless, the aggregate impact becomes relevant when they are properly coordinated. In this context, we consider the frequent case of a group of EVs connected to a parking lot with a photovoltaic facility. We propose a novel strategy to optimally control their batteries during the parking session, which is able to satisfy their requirements and energy constraints. EVs participate in a noncooperative energy market based on a smart pricing mechanism that is designed in order to increase the predictability and flexibility of the aggregate parking load. Differently from the existing contributions, we employ a novel approach to minimize the degradation of batteries. The effectiveness of the proposed method is validated through numerical experiments based on a real scenario.

On Controlling Battery Degradation in Vehicle-to-Grid Energy Markets

The increase in electric vehicles (EVs) and distributed generations (DGs) has brought significant voltage fluctuation issues to distribution networks. Since simultaneous active and reactive power coordination can make voltage regulation more efficient, optimal coordination of active/reactive EV charging/discharging is an attractive solution. This work contributes to addressing the challenge above by devising an optimisation-based coordination framework for EV charging/discharging for voltage support in distribution networks. The proposed framework is based on model predictive control (MPC), and includes reactive/active power management, as well as EV behaviour modelling. The proposed framework minimises network voltage deviation and electricity cost of electric vehicle charging stations (EVCSs). An EV behaviour modelling is integrated into the MPC scheme by using a Markov Chain Monte Carlo (MCMC) method. A case study is conducted on a 33-bus distribution network with photovoltaic (PV) generation and multiple EVCSs, demonstrating effective voltage regulation and cost-saving of the proposed MPC-based optimisation framework.

Optimal Coordination of Electric Vehicles for Voltage Support in Distribution Networks

This work concerns model predictive control of multi-energy buildings with shared network capacity constraints. More specifically, it is concerned with how to effectively coordinate a large number of locally constrained and coupled buildings without violating indoor comfort and network constraints, whilst maintaining the privacy of building owners. Buildings are regarded as agents and modelled using a hybrid system approach within a multi-energy context. The developed models consider buildings connected to constrained electricity and gas supply networks. Building energy resources can include battery devices, heat-pumps or micro-turbine based combined heat and power units to satisfy both the local electricity and heating demands. The building and network modelling is incorporated into a predictive control scheme to optimally coordinate multiple buildings, with the objective of minimising individual building gas and electricity costs. However, for large systems consisting of many buildings, the computation time required to coordinate and optimise building operations in a centralised manner becomes prohibitive. Hence, in order to devise a scalable control framework, a decentralised approach is employed, where each building agent is required to solve a tractable Mixed Integer Linear Program at each time step. By doing so, multiple buildings are cost-effectively coordinated and operated so as to achieve a common target with significantly reduced computational time. The proposed approach can handle an arbitrarily large number of buildings and is validated through a relevant case study.

Alessandra Parisio

Papers

Optimization-Based Ramping Reserve Allocation of Aggregated BESS for AGC Enhancement

Optimal Frequency Restoration of Inverter-Interfaced Microgrids via Distributed Energy Management

On Controlling Battery Degradation in Vehicle-to-Grid Energy Markets

Optimal Coordination of Electric Vehicles for Voltage Support in Distribution Networks

Decentralised Predictive Control of Multi-Energy Resources in Buildings