Abstracts:Neutral grounding resistors (NGRs) are commonly used in medium voltage (MV) distribution systems for industrial facilities. The application of NGRs becomes considerably more complex when multiple power sources, including on-site generation, are involved. Industry standards and best practices have evolved over time, and the sizing of each NGR cannot be performed in isolation. Coordinating NGRs throughout a distribution system is critical for the protection of generators, transformers, and feeders during ground faults, especially since each individual NGR affects the fault current seen by the entire system. Additionally, introducing NGR monitors capable of verifying continuity of the ground connection when decoupled from the bus, while remaining compatible with multiple sources, is an important consideration. This paper aims to offer recommendations and application guidelines to assist engineers when sizing NGRs for the overall MV power distribution system, including generators and transformers, to ensure comprehensive protection of all equipment within the specified system and application. NGR sizing aims to minimize equipment damage and ground-fault current, reducing the risk of ground faults escalating into phase-to-phase arcing faults and enhancing personnel safety. NGR monitoring is also discussed since it is a requirement in some jurisdictions. An applicable case study for a paper mill is included that demonstrates the NGR sizing process, calculations, and considerations.

Abstracts:Electrical equipment, fitted with arc quenching technologies, have been employed and have been providing personnel and equipment protection in many global installations for over two decades. This technology continues to evolve, advance, and provides significant reduction of arc incident energy. However, a limiting factor has become the actual standards which define some of the fundamental aspects of its design and applications. This work outlines how the present generation of arc quenching technologies continue to reduce arc incident energy and improve safety within switchgear, motor control centers or control panels. Very detailed testing results will provide conclusive evidence of a superior level of protection to not only the protected equipment and process, but also to personnel as well. The factory and site acceptance testing criteria for arc mitigation systems, to guarantee the correct operation of the system, will be discussed as well. Common myths and misconceptions surrounding arc quenching technologies, such as the system current impact expectations when using arc quenching technologies, are also covered.

Abstracts:Using a connector not rated for the application and improper installation is a cause of power interruption in industrial and commercial facilities. This paper provides a primer for proper selection and installation practices to improve electrical distribution system reliability and performance. The goal of any electrical system is to perform functionally for the life of the system. This paper reviews the types and technical characteristics of electrical connectors that are used for distinct functions within the overall electrical system, such as grounding, bonding, and power connections. Environmental considerations such as direct burial, wet locations, and sunlight resistance are addressed. New connector applications such as line side of the service ratings are introduced. The paper also addresses the characteristics of connectors and installation practices for applications over 1000 Volts. Connector installation information, such as torque requirements, finely stranded conductor impacts, hole spacing guides per the National Electrical Manufacturers Association (NEMA) standard, voltage limitations and temperature rating ampacity impacts are outlined.

Abstracts:Hydrogen is a versatile fuel source, and electrolysis stands out as a promising method to produce hydrogen. Traditionally, the power distribution system for hydrogen electrolysis is designed for the individual electrolyzer modules with DC (direct current) power requirement in the range of 1 to 5 MW. The power supply to these modules is accomplished in three steps starting from high voltage to medium voltage and medium voltage to low voltage transformations. The last step involves the rectification process from AC power to DC power to electrolyzers. Supplying DC power to a gigawatt-scale hydrogen plant comprises of multiple power transformers, rectifier transformers and rectifiers in parallel leading to larger footprint, and higher capital and higher maintenance costs. Accordingly, this paper explores an alternative approach, where high-power DC distribution system, like those used in aluminum potlines, for hydrogen production. These are proven technologies used for long time in mining and metals industry. Operational experience of such a system highlights its reliability, efficiency, cost-effectiveness, and enhanced adaptability. This paper addresses the critical role of high-power DC distribution systems in realizing the full potential of hydrogen electrolysis for sustainable energy production.

Abstracts:This work introduces the concept of dc C-areas in time-current characteristic plots (TCCs) for establishing a reference of dc arc-flash (dc AF) incident energy (IE) during the protection and coordination study. C-area plots represent a constant allowable incident energy for a piece of equipment while considering arc flash input data variability. This work introduces the C-area application for dc equipment. The dc C-area reference plots allow protection engineers to select overcurrent protective device settings in TCCs while keeping track of the allowable incident energy. This work explains the theory and derivation of the dc C-areas, the impact of the input parameter variability, and provides a detailed explanation of the data collection challenges for performing a dc arc-flash incident energy analysis. The dc C-area methods introduced in this paper are based on industry accepted dc arc-flash calculation equations, yet novel concepts in dc C-areas such as arc elongation and conductor erosion effects are discussed along with their effects. This paper also includes application examples of dc C-areas for battery energy storage systems (BESS) and photovoltaic (PV) systems equipment protection and coordination studies. The protection and coordination device setting selections made by means of dc C-areas are then compared to actual dc arc-flash incident energy calculations performed using commercially available power system analysis software to validate the methodology.

Abstracts:Although essential for the development and well-being of society, harnessing electricity carries significant risks. In Brazil, the state of electrical safety has become particularly worrisome, given recent fatality statistics. Hence, it is essential to understand electrical accidents as a social phenomenon to formulate effective prevention strategies. This study analyses deaths due to electric shock in Brazil between 2012 and 2021, using official data from the public health system (DataSUS). The study shows that states with lower Human Development Index (HDI) have a higher rate of occurrences. The research also examined other aspects, such as the victims’ background and the location of the accidents. Finally, some guidelines for creating a program to reduce deaths from electric shock in buildings and overhead electric power distribution are presented.

Abstracts:Modern control systems in the automotive industry aim to improve ride comfort and handling performance. In this context, non-uniform sampling, transmission delay, and partial measurements in states are increasingly important features to consider. This paper presents design conditions formulated via linear matrix inequalities (LMIs) for an output feedback controller that considers both non-uniform sampling and time delay in the state transmission. Moreover, for a more realistic setting, we consider a time-varying vehicle load. To address these challenges, the active suspension system (ASS) will be modeled as a Takagi-Sugeno (T-S) fuzzy system, and an augmented Lyapunov functional is proposed. This functional also includes information from the membership functions (MFs), allows the design conditions to be relaxed. First, we propose a state feedback control, consequently, we derive the desired static output feedback (SOF) control design conditions. Simulations and practical results are presented to demonstrate the effectiveness of the proposed controller.

Abstracts:A new approach to controlling quadcopter unmanned aerial vehicles (UAVs) incorporating fractional calculus and a new prescribed performance function (PPF) in the design of a nonsingular terminal synergetic control (NSTSC) to control the quadcopter's attitude dynamics. Employing fractional calculus enables the establishment of a flexible control design that improves tracking accuracy, minimizes chattering, and enhances the robustness of the controller. Moreover, the new PPF is a simple function employed to improve the transient response and guarantee the controller's convergence within a finite time while simultaneously allowing the overshoot due to the rapid change in the quad-copter thrust directions. The objective of the study is to evaluate the efficiency of the proposed controller in tracking the desired orientation with accuracy while ensuring finite time convergence of the error. Furthermore, the Lyapunov technique is employed to demonstrate the stability of the closed-loop systems. The experimental results show that the use of finite time fractional nonsingular terminal synergetic control (FTFNTSC) leads to superior performance in tracking the quadcopter's orientation trajectories and more effective handling of system variations and external disturbances with a fast transient response, making it more promising approach for the morphing quadcopter system compared to the traditional synergetic control approach.

Abstracts:Wastewater from the semiconductor industry typically contains substantial amounts of total ammonia nitrogen (TAN) and fluoride that can have adverse effects on the environment. The present study examined the efficacy of a sonoelectrochemical system which applies ultrasonic waves to an electrochemical process in removing these species from wastewater. Application of the sonoelectrochemical process with a current of 2 A, and a sonication frequency of 40 kHz to synthetic wastewater resulted in a TAN removal efficiency of 52.2% . pH was the main factor affecting TAN crystallization, with alkaline conditions in combination with a sonication frequency of 40 kHz being optimal for TAN removal. In terms of fluoride removal, application of the sonoelectrochemical process for 1.5 h achieved a removal efficiency of 98% at pH 7. The main precipitates obtained were Al-F complexes. The present findings indicate that the sonoelectrochemical process is a feasible and cost-effective approach for use in the recycling of industrial wastewater.

Abstracts:This paper investigates the fault current characteristics of doubly-fed induction generators (DFIGs) in weak grid scenarios, addressing the limitations of existing methods that assume a predefined voltage dip and neglect the influence of DFIGs on post-fault voltage. A transient fault voltage model is proposed to accurately capture the interaction between DFIGs and weak grid impedance, which significantly affects fault current calculation. The model introduces an additional pole to account for fault voltage transients, addressing computational errors in low grid strength conditions. Furthermore, a fault current expression for DFIGs under severe faults, particularly after crowbar activation, is derived, revealing the impact of external grid impedance on transient fault currents. Case studies with expanded fault scenarios and hardware-in-loop experiments demonstrate the superiority of the proposed method over existing approaches in weak grid applications.