The IEEE 1584-2002 standard provided guidelines for applicable techniques to determine arc current, incident energy, and electrical arc limits. Therefore, this article presents the development of a software tool for calculating incident energy in electrical arc events, which helps determine the risk label and appropriate Personal Protective Equipment (PPE) for electrical risk mitigation based on the 2018 revision of IEEE 1584.

This paper proposes a new integral methodology to overcome hidden failures and mitigate the electrical hazard due arc-flash events. This methodology overcomes the drawbacks of legacy protection functions due hidden failures. Also, considering the requirement to limit the maximum arc-flash hazard, a restriction has been implemented to coordinate the protection devices in the proposed methodology. The application results of the proposed methodology are shown on a steel manufacturer user showing the improvements by reducing the probably incident energy feasible due to arc-flash events and show how legacy protection functions would fail to operate in such scenario.

This article proposes a new integral protection method of electrical systems for fault conditions independent of the magnitude or affected parameter, which includes conventional and high impedance faults. Additionally, the proposed method implements a simpler logic process than traditional protection methods. The method operates in a differential mode to overcome the drawbacks of legacy protection functions related to the maximum incident energy within the protected zone. This article presents the assessment of the proposed method to overcome hidden failures due to high impedance faults and to mitigate the arc-flash hazard in lines and transformers. The results of the proposed method on a steel manufacturer user are shown for different fault impedance conditions, linear and nonlinear characteristics. The results show the enhancement of clearing times and logic simplification due to the selective response of the proposed protection method in comparisson to traditional protection functions. This research presents a comparison against legacy protection functions showing how traditional protections would fail to operate in high impedance scenarios leading to unsafe working conditions.

This paper proposes a new integral methodology to overcome hidden failures and mitigates the electrical hazard due to arc-flash events during the protection of electrical systems. This methodology overcomes the drawbacks of present-day protective functions and their limitations. Also, considering the requirement to limit the maximum arc-flash hazard, a restriction has been implemented to coordinate the protection devices in the proposed methodology. The application results of the proposed methodology are shown on a steel manufacturer user showing the improvements by reducing the probably incident energy feasible due to arc-flash events.

This article presents a bibliographic review accompanied by two electric arc models that can represent both dynamic characteristics for the first and static for the second. The proposed models were developed from the combination and modifications of the classical Cassie and Mayr equations for the dynamic case and the representation of the V-I characteristic for the static case. The equations have been expressed in a form suitable for EMTP-ATP incorporation using the subroutine models that use the nodal analysis method for solving equations. Simulated and experimental results show a pleasant approximation.

This paper presents a methodology to manage cogeneration power injection and protection system adjustments in a steel manufacturing industry. The study begins with an analysis of the feeder, resulting in the scenarios in which the protection system could fail with the inclusion of cogenerators. After this, a series of restrictions are defined, under which the optimization of the power injected in cogeneration and the adjustments of the protections are carried out. Finally, a list of tests on the generated algorithm are presented. These tests are performed on a model of the case study network developed in Matlab/Simulink.

This article presents a methodology to evaluate protection schemes in grids with nonlinear loads. For this purpose, a protection library developed in MATLAB/Simulink is presented, which is complemented with a communications system and an electric arc furnace (EAF). Subsequently, an application example is shown, in which the protection system of a steel manufacturing industry is developed, considering the linear and nonlinear loads, and tested using the methodology compound of four stages: the definition of the protections, the settings, the fault analysis, and the hardware implementation.

This article proposes a new adaptive commissioning methodology for arc flash mitigation in steel manufacturer users considering the Tap-to-Tap varying current consumption. This process is achieved through adaptative protection settings computed to reduce the total clearing time of relays adding the restriction of the incident energy. The proposed methodology carries out the detection of abrupt changes in current consumption to detect Tap-to-Tap change in operation stages of electric arc furnaces. The application of this methodology is performed on a steel manufacturer user and shows the reduction of the incident energy values according to Tap-to-Tap operation cycle.

This paper proposes the development of a small-scale prototype of a steel manufacturer user. This work arises from a requirement in the test of new technological processes in steel production, giving a high level of trust to industrial facilities, this requirement is referenced through the assessment of working groups related to steel production. The paper presents an evaluation of the operational conditions of the electric arc furnace, the rolling mill loads, and the communication system. The work aims for the integration of small-scale prototypes that simulate the operation in a steel manufacturer user. This prototype will be used for the test of new control, protection, and operation methodologies of steel manufacturer users.

This paper presents the results obtained from the simulation and development of an arc flash protection library for MATLAB/Simulink, including the models of the protection and grounding systems to study its influence on the incident energy. First, the background on the protection system, incident energy computation, and grounding systems is given in Section II. The background is used to present a series of examples on the incident energy computation and the selection of the parameters selected for the development of the arc flash protection library. Section III presents a methodology for the development proposed protection library. Section IV presents a case study on a local steel manufacturer user. Finally, conclusions and future work are shown.

In this paper the feasibility study of the use of solid-state transformers to feed an electric arc furnace is carried out. The proposal is based on the specifications of an electric arc furnace transformer of 28kVA installed in a local steel manufacturing facility. Thermal and chargeability tests are carried out on solid state transformers in order to determine their performance and the level of deterioration caused by thermal stresses to which they could be subject in electric arc furnace installations. This will allow the definition of the level of wear according to the overload conditions as well as the development of a methodology to calculate the wear and reliability of the equipment, and thus be able to assess its performance compared with conventional oil-filled transformers.

This paper presents the results obtained of the simulation and implementation in hardware in the loop of fuses and overcurrent protections. First, the steps developed for construct the different blocks in MATLAB/SIMULINK considering the details for the curve approximation in the fuses are presented. Consequently, their implementation using the Dspace 1104 and TI 280F337S boards are presented, describing the characteristics of the signals measurement and the construction of the tripping module and interconnection of all the components of the test grid. Finally, the results obtained in simulation and those obtained whit the hardware in the loop system are compared.

This article proposes a new adaptive protection setting methodology for steel manufacturers, aiming to reduce miscoordination between main feeders and current consumptions due to fault clearance or high load disconnection. By detecting abrupt changes in current consumption, the computation of different protection settings may be achieved. The application of this methodology is performed through the assessment of a steel manufacturer who sustained an arc blast of one of their protection cells, and a description of the way in which the proposal permits avoidance of such catastrophic conditions.

This paper suggests that the presence of microwaves in high voltage transformers is caused by the creation of negative resistance associated with an internal parasite oscillator.Full performance of the electric transformer includes not only forced oscillations like the fundamental and its odd harmonics, assuming the input voltage sinusoidal and the nonlinear coil unpolarized. There also appear free oscillations. They have features associated with forced oscillations, so it might be better to characterize them as free-forced electric waves. We studied a circuit including a nonlinear core driving by two a-c waves designated fundamental and third harmonic. With the two input currents flowing through the coil, a complete set of modulation sidebands is generated.Our research suggests that wireless acquiring and further processing of these free microwaves may reveal new transformer features as aging.We review these concepts and offer some radiated microwaves measurements results taken below 115 KV industrial and dwelling electric lines circuits. Acquisition of microwaves is performed with a typical amplifier followed by a personal computer. Further, we realized a lab experiment with 16, 75 KVA distribution transformers looking for signatures related to forced aging. Transformers were conducted to failure by installing them in a high temperature camera. Measurements and processing of microwaves generation is a proposes a new way to assess electric power quality.

The presence of inverter based renewable resources has introducing new challenges on transmission systems due sudden loss of several MW after voltage and frequency excursions. These sudden disconnections have been related with a fault ride through control in voltage and frequency excursions following PRC-024 standard. The NERC Inverter-Based Resource Performance Task Force has expressed the necessity for a full ride-through standard with clear requirements as to how the resource can behave in terms on control and protection aspects. In consequence, this article addresses the problem to define the control and protection that can be taken under frequency and voltage excursions to avoid disconnections. For this purpose, this article proposes a new magnitude and frequency computation with computations delays under 16 ms and the use of new detection techniques to add new control and protection functions to the inverter based renewable resources.

The emergence of applications which require high-voltage switches has created a tendency to use semiconductor device series stacks. These series stacks permit operation at blocking voltages above semiconductor elements' nominal voltage. Insulated-gate bipolar transistors (IGBT) are currently utilized for controllability and switching speed, when these topologies are employed. The main challenge therewith is guaranteeing voltage balance between IGBTs, both when blocked and when switching transistors. Most of the methods which have been proposed to mitigate static and dynamic voltage unbalances increase transistor losses. The series stack loss-less high voltage switch (LHVS) which mitigates voltage unbalances, thus reducing switching losses, is presented in this paper. LHVS consists of a circuit, which ensures soft IGBT switching, an energy recovery circuit, and a gate delay compensation circuit. Additionally, the insulation voltage level is guaranteed to be equal between control circuit and high-voltage side of each IGBT. The operating principle of the LHVS is detailed in this paper, as is experimental validation which has been performed for three series stack modules. Static unbalances are reduced to 1%, while the differences between collector-emitter voltage curves in switching "ON" do not surpass 8 ns, and switching losses are reduced by 41%, as compared to the hard-switching topology.

The real-time data flow over TCP/IP (Transmission Control Protocol/Internet Protocol) between running simulation models allows evaluating the designed models and its communication capabilities. This paper presents a proposed methodology for the data flow in real time between modeled components of a protection scheme with local control, for a distribution system in Smart Grids. The proposed methodology specifies the characteristics of the modeled components, as Intelligent Electronic Devices (IEDs) and a Local Control Center (LCC). In addition, the communication network architecture based on TCP/IP protocol to allow the data flow is selected. In order to evaluate the methodology, a case study is implemented in MATLAB/Simulink. In the case study test, the LCC response time is measured. The obtained results in the LCC response time measurements were lower than 110 ms.

This paper presents the results obtained of the simulation and development of a protection library for MATLAB/Simulink, including the models of different functions that will be included in future schemes of protection, and digitals relays multifunction construction. First of all, a methodology exposing how the library was constructed, including the different models, and their communication architecture are presented. Secondly, a case of study in a Steel Arc-furnace, with a new adaptive protection coordination scheme using models of the library is proposed. Finally, the results of the simulation are exposed and a description of how this case of study can be used for comparison of protection schemes is described.

The emergence of high voltage conversion applications has resulted in a trend of using semiconductor device series associations. Series associations allow for operation at blocking voltages, which are higher than the nominal voltage for each of the semiconductor devices. The main challenge with these topologies is finding a way to guarantee the voltage balance between devices in both blocking and switching transients. Most of the methods that have been proposed to mitigate static and dynamic voltage unbalances result in increased losses within the device. This paper introduces a new series stack topology, where the voltage unbalances are reduced. This in turn, mitigates the switching losses. The proposed topology consists of a circuit that ensures the soft switching of each device, and one auxiliary circuit that allows for switching energy recovery. The principle for the topology operation is presented and experimental tests are performed for two modules. The topology performs excellently for switching transients on each of the devices. The voltage static unbalances were limited to 10%, while the activation/deactivation delay introduced by the lower module IGBT driver takes place in the dynamic unbalances. Thus, the switching losses are reduced by 40%, when compared to hard switching configurations.