Contribution to decision making in power system driven by distributed generation

In this thesis, we categorize the challenges that Distribution System Operators (DSO) are facing into two separate sets of articles. After the introduction, the initial set of articles (chapters 2, 3, and 4) focuses on network operation, addressing challenges, and suggesting creative solutions to enhance the resilience and effectiveness of decentralized energy systems. The subsequent set of articles (chapters 5,6,7 and 8) redirects attention to the exploration of energy communities, unveiling the potential of localized, participatory energy ecosystems.
Chapter 2 can be summarized as follows. In an electrical system where decentralized and embedded productions are becoming increasingly important, it is essential to ensure a good understanding of their behavior at their operating limits. One of the most important operating limits is when the system frequency approaches 50.2 Hz. At this frequency, following the old requirements, many existing European PV inverters have to be disconnected. In such situations, we demonstrate that the variance of the frequency measurement taken at every PV inverter plays a key role. It has been demonstrated that this variance is a good thing from the system's point of view as it allows for a gradual disconnection, leading to a controlled variation of the frequency.
To address the challenges due to decentralized energy generation and emerging loads like electric vehicles, DSOs implement Active Network Management (ANM) as a short-term strategy to manage efficiently power injection and consumption, avoiding congestion without the need for heavy infrastructure investment. ANM requires knowledge of the system state, necessitating the placement of measurement devices throughout the network to ensure accurate estimates. In that context, chapter 3 introduces a new method for placing measurement devices in distribution networks. In contrast to the previous research works which rely on objectives for the placement such as state estimation accuracy, the proposed method incorporates ANM considerations in the process of determining the optimal locations, aiming to enhance ANM quality. Simulation results on a test distribution network demonstrate the superiority of this approach, leading to reduced curtailment of generators and improved overall performance.
Grid monitoring strategies, like the one presented in Chapter 3 is the process of collecting data from sensors across a distribution grid and sending it to a central system (SCADA) to identify and diagnose problems, improve reliability, and save energy and money. The increasing complexity of power flows and the need to manage them using ANM strategies requires accurate data and strong defenses against cyber attacks. A proof-of-concept software called "MonitORES" was developed using Hyperledger Fabric to demonstrate how a distributed ledger technology (DLT) such as blockchain can be used to monitor and control generation units within ANM schemes, with improved resilience against cyberattacks. It is this work that is presented in the chapter 4.
Chapter 5 opens the second set of articles aiming to explore renewable energy communities (REC).
The main goal of the E-Cloud, one of the first projects of energy communities in Wallonia, as with every microgrid, is to maximize the consumption of energy produced locally. To reach this goal, based on consumption profiles of customers willing to participate in the E-cloud and given some local restrictions (e.g. wind turbines cannot be put everywhere), an optimal mix of green generation sources (in kW) and local storage (in kWh) needs to be computed.
Then according to this computation, the required generating units and storage devices are installed. A repartition mechanism grants the customer a share of the generated electricity and storage capacity. These shares are either computed offline or dynamically adapted online.
The project aimed to test two models: either the DSO or a producer owns and operates the storage device.
Two information flows (real-time for the operation of the storage facility and ex-post for its settlement) are needed to ensure correct information exchange with the wholesale market. These information flows are completed thanks to a forecast that provides members of the E-Cloud the full capability to anticipate and obtain the maximum benefits of the local generation.
The expected benefits for the customer are a reduction of their electricity bill by a minimum of 10\%. Societal benefits should also arise: 1) easing the technical integration of renewables generation embedded in the distribution network, and 2) avoiding extra investment in the DSO network.
The next chapter proposes that the success of local REC, now foreseen by the European Union directives but also growing worldwide, will rely on the appetite of consumers and investors. This is not obvious when the target local area is a residential community where people have varying expectations. Based on Bayesian game theory (also called a game of incomplete information), the purpose of this paper is to define an approach for determining, from the point of view of the renewable energy investor, the level of production capacity and energy price that needs to be offered to the consumers.
Chapter 7 explores how the blockchain approach can be employed to foster this REC market. The goal is to determine the design that should allow a DSO to accept peer-to-peer energy exchanges based on a distributed ledger supported by blockchain technology. To this end, an evaluation is conducted integrating several designs based on criteria such as acceptance of the wholesale/retail market, the resilience of the consensus to approve a block, the accuracy, traceability, privacy, and security of the proposed schemes.
Chapter 8 poses that, despite its success and large use in other crypto-currencies, Proof of Work's disadvantages are high latency, a low transaction rate, and a high energy expenditure, making it a less-than-perfect choice for many applications. In addition, the validation of transactions is not carried out with a definite temporality. However, for certain use cases such as auctions or the exchange of energy in the REC context, there is a need for this temporality. The purpose of this article is to propose a new type of consensus that is faster, less energy-consuming and that can be synchronized with a time reference. The core of the reflection is the use of the Condorcet voting mechanism to determine the miner.
The last chapter sets the main conclusion of this research.
Two appendixes show other works conducted with fellow researchers during this PhD research journey.