Search

The energy transition is aimed to take advantage of the operational flexibility of hydropower to extend the integration of intermittent renewable sources. Consequently, the hydrogenerators will have to operate in regimes far away from their designed best-point operation. In order to accurately assess the impact, this paper presents a useful approach to determine the overall operating efficiency of synchronous generators under intermittent operation. An accumulated average efficiency (AAE) model is proposed and compared against an alternative approach; the weighted average efficiency (WAE) model. It is found that the WAE approach produces unrealistic low efficiencies when the generator operates in synchronous condenser mode (SCM) for long periods. In general, the AAE supersedes the WAE for all the different load distributions that were investigated. This was further illustrated by a worked example and by constructing more complex load distributions. A load distribution dominated by SCM yields a difference as high as $33.18 \,\%$ , while an even distribution deviates $1.43 \,\%$ in their respective efficiencies. Finally, a yearly on-site measurement of our studied $103 \,\mathrm{MVA}$ generator’s concentrated load distribution revealed a discrepancy of $0.67 \,\%$ , which is a significant deviation considering what the operating regime would mean in terms of economic implications. [ABSTRACT FROM AUTHOR]

Achieving the low-carbon transition of power systems requires the coordination of renewable energy generation and other emerging electricity technologies. Their technical indicators are changing rapidly since these technologies are in the initial stages of development. Determining the technical and policy targets for achieving the low-carbon transition is critical for regulators and power system planners. This paper defines this problem as a backcasting problem, whose concept is derived from environmental science research. We introduce it into the power system planning field and innovatively model it as a bi-level optimization problem. According to the characteristics of the backcasting problem, an improved barrier method is proposed to solve it efficiently. The effectiveness of the proposed model and algorithm are verified through case studies on a modified Garver’s 6-bus system and a realistic Northwest China power system, and they are compared with state-of-the-art solution techniques. The results of the backcasting problem provide a new perspective on the economic impacts of the low-carbon transition and are helpful in energy policy formulation for power systems. [ABSTRACT FROM AUTHOR]

The papers in this special section focus on cyberattacks, strategic cyber-foresight, and security applications. Reports of cyber-attacks against individuals, organizations, and businesses are on the rise. Attackers usually have a deliberate and malicious intent and may involve the criminals taking advantage of flaws in software code, using tricks to get around antivirus tools, and or exploiting unsuspecting users into divulging sensitive information. Often launched by isolated amateurs, or criminals that belong to often well-structured organizations, with money, motivation, and an agenda, such attacks are frequently designed to temporarily or indefinitely disrupt services of a host connected to the internet or simply grind institutional systems to a halt. Popular among social engineering, malwares employed in such attacks are what has come to be known as a distributed denial-of-service attack, which affect the infrastructure of websites, computer servers, and other network resources resulting in the compromise of critical personal or institutional data. Across the globe, these attacks are growing in sophistication, and they tend to have serious economic and security consequences for their targets. The chaos they precipitate can be life-threatening, and their cost can be considerable to target organizations or nations. Such features also affect the dynamics of collaboration among firms, thus posing negative effects on innovation dynamics. [ABSTRACT FROM AUTHOR]

This paper proposes a new and comprehensive approach for optimal sizing and placement of a wind farm (WF) in a radial distribution network (RDN) while considering several factors associated with its reliability, operation, economics and environment impact. The consideration of the reliability aspect is essential to correctly assess the impacts of forced outages of wind turbines in the field. In this context, a sequential Monte Carlo simulation-based technique has been formulated to evaluate the performance of the WF with varying capacities at different locations in the RDN. Additionally, the capability of the WF to perform Volt-Var and Volt-Watt control has been capitalized on to provide voltage support to the grid in compliance with international standards (IEEE 1547-2018). Finally, a combination of Analytic Hierarchy Process and Technique for Order Preference by Similarity to Ideal Solution has been used to assess and determine the optimal size and location of the WF, based on a selected set of performance criteria, namely cumulative violations of the steady-state voltage range, cumulative losses in RDN, cumulative violations of the line thermal rating, levelized cost of energy, and reduction in carbon emission. The proposed approach has been validated considering different modes of voltage control on the standard 33-bus RDN system. [ABSTRACT FROM AUTHOR]

Three-phase unbalance could have significant impacts on the secure and economic operation of a low-voltage distribution system. With the deployment of smart meters and the emergence of phase switch devices (PSDs), more efficient schemes for mitigating three-phase unbalance are expected by utilizing numerous measurement data and the installed PSDs in low-voltage areas. Therefore, a bi-level optimal phase switch device placement model for mitigating three-phase unbalance is proposed in this work. In the upper-level model, the PSD placement strategy is optimized by minimizing the total costs of PSD installation and operation costs of low-voltage areas determined in the lower-level model. In the lower-level model, the operation costs of low-voltage areas for typical days are minimized based on the PSDs and their locations determined in the upper-level model. The proposed bi-level model is tested by an actual low-voltage area of Zhejiang province, China, and the effectiveness of the optimal PSD placement model for reducing the total investment and operation costs of the low-voltage area demonstrated. [ABSTRACT FROM AUTHOR]

Daily headlines stress the ways modern technologies disclose their most dystopian possibilities; this magazine is replete with examples of innovative technologies that prompt considerations of their unethical applications. Numerous approaches have already been proposed to advance critical thinking about the social, cultural, environmental, and economic implications of tech innovation, such as tech literacy and philosophy of technology. What these intellectual traditions have shown is that while the negative effects of technological innovations may be unprecedented, they can be foreseen, and, more importantly, mitigated through more intentional and skillful engineering. Nevertheless, systematic efforts to address these impacts remain peripheral to the engineering profession, with technological artifacts deemed value-neutral, and intervention often seen as luddite and unenforceable. While this situation suggests a need for systemic changes across academic and industry contexts, it also points to an immediate need to address the uptake of critical thinking about the implications of tech innovation within the engineering community. [ABSTRACT FROM AUTHOR]