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There has been prior research exploring the exposure of common electrical cords and cables to fire, but that has traditionally been at the lab scale and under near steady-state exposures. The goal of these experiments was to expose six types of cords and cables in a room-scale compartment with a fuel load sufficient to drive the compartment through flashover. The basic test design was to expose the cords and cables on the floor of a compartment to a growing fire to determine the conditions under which the cord/cable would trip the circuit protection device. All of the cords were energized and installed on a non-combustible surface. The six cables and cords were protected by three different circuit protection devices which were remote from the thermal exposure. This configuration resulted in 18 exposures per experiment. The room fires experiments consisted of three replicate fires with two sofas as the main fuel source, two replicate fires with one sofa as the main fuel source and one fire with two sofas and vinyl-covered MDF paneling on three walls in the room. Each fuel package was sufficient to support flashover conditions in the room. The average peak heat release rate of the sofa fueled compartment fires with gypsum board ceiling and walls prior to suppression was 6.8 MW. The addition of vinyl covered MDF wall paneling on three of the compartment walls increased the pre-suppression peak heat release rate to 12 MW. In each experiment during post flashover exposure, the insulation on the cords and cables ignited and burned through, exposing bare wire. During this period, the circuits faulted. Assessments of both the thermal exposure and physical damage to the cords did not reveal any correlation between the thermal exposure, cord/cable damage, and trip type.

In electrical power systems, cords and extension cords are exposed to mechanical damage and other insulation stresses. Mechanical damage to stranded conductors can reduce locally their cross section or break them and cause anomalous local conditions of overheating or arcing. The ordinary protective devices cannot detect the series faults that persist, so the fault point remains energized and is subject to electric shock and fire hazards. Effective protection can be accomplished by implementing active and passive measures: installing arc-fault circuit interrupters or arc-fault detection devices, able to detect arcing faults, or wiring the circuits with a grounding protection conductor to involve the ground in every fault. In this way, residual current protective devices (residual current devices or ground fault protective devices) quickly protect the series faults not only with arc, but also without it. Ground-fault-forced cables facilitate by design the conversion of any kind of cable fault to a ground fault. They are particularly recommended for cords and extension cords, internal circuits to grounded equipment, uninterruptible power system continuity circuits, aircraft circuits, road tunnels, data centers, refrigerated containers parks, residences, and hospitals.

The automated microcontroller-based circuit protection and control system is integrated with IoT element, which consisted of both hardware software components, and communication devices. The designed system is to acquire the electrical parameters such as current and voltage as well the power consumption using sensors. ThingSpeak is engaged, mainly used to acquire data from the microcontroller via wireless communication, to further analyse and visualize it in the required form and sends SMS notification to the user through Wi-Fi, such as over/under current, over/under voltage, & excessive power consumption, depending on the data analysis. Once user received notification, remedial action can be further taken to isolate faulted part from circuit, or to take desired action for safety purpose. The designed prototype is enhanced circuit protection (automated), incorporating data storage, monitor/control of electrical loads intelligently and offers user safety and security of the electrical operation.

Room temperature switchable dielectric materials have great potential in applications such as smart sensors, energy storage and circuit protection. In this paper, a novel switchable dielectric system, Span80/HD-PET film system (SHPS), is designed and manufactured based on a “three-layer” model. And the system is built up by stacking all organic components, including the Span80/hexadecane (Span80/HD) mixture and the polyethylene terephthalate (PET) film. The SHPS shows obvious dielectric switching properties when the Span80/HD mixture goes through solid–liquid phase transition. For example, the dielectric switch can be triggered at 13.7 °C during cooling and shows good cycling stability. By changing the thickness of the PET film, the highest switching ratio can be 270.5. Besides, the switching temperature can be adjusted by changing the components of the organic mixture.

For many years, industrial manufacturing plants in the process industries, along with hospitals, schools and commercial building owners have installed used circuit breakers in panelboards, switchboards, switchgear and motor control centers with reconditioned replacements. Often times, due to the vintage of existing electrical equipment, reconditioned circuit breaker replacements are the only available option. Is this practice safe? Some recognized industry standards such as the Professional Electrical Apparatus Reconditioning League (PEARL) ANSI Accredited Electrical Equipment Reconditioning Standard (EERS) say yes. For Molded Case Circuit Breakers (MCCBs), the recently published U.S. National Electric Code NFPA70-2020 says no. This paper will review applicable global and regional industry standards for circuit breakers and offer clarity around many words including “rebuilt”, “refurbished”, “remanufactured”, “reconditioned” and “renovated” and terms such as “field-modified”. The paper will briefly review design and test standards for new 600-volt class molded-case, insulated case and low-voltage power circuit breakers followed by standards covering accepted practices for reconditioned products, with focused guidance on proper application to assure safe and reliable system circuit protection.

The vehicle electrification era is here, bringing with it a wave of innovative technologies and exponential advancements. However, there are important safety implications to be considered as these technologies and market trends are adopted. What are these trends and how do they impact circuit protection of electric vehicles?

The Solid State Circuit Breaker (SSCB) is conveniently used to substitute classical circuit breaker for the applications where the circuit breaker works with high mechanical stress (i.e. high vibrations, shock etc) and the dimension and weight must be reduced. Among the SSCB family, the snubberless SSCB have been recently introduced for particular application that differs from the classical SSCB because waste the load energy in the SSCB itself during the turn-off time. This is possible by using particular IGBT/MOSFET drivers with active clamp circuits. In this paper the authors find the limits of this class of SSCB circuits and define the key elements that act on the them.

With increasing dependence on precision electronic equipment, self-protection is becoming essential. The protection circuits commonly used before were fuses and circuit breakers which, however, they are not enough for the current need of high-speed protection circuits and automated engineering logic. In this paper, we develop a new ultrahigh-speed protection circuit, which is over exceeded 20 times faster than traditional circuits and has the ability to self-recover when any failure occurs. With the new circuit developed, it is not necessary to do manual restart and will meet the future needs of protection for electronic precision equipment. This design provides greater convenience and reliability for the unmanned equipment for the future.

In electrical power systems, the cords and extension cords are exposed to mechanical damage and other insulation stresses. Mechanical damage to the stranded conductors can reduce locally their cross section or break them and cause anomalous local conditions of overheating or arcing. The ordinary protective devices cannot detect the series faults that persist; so the fault point remains energized and subject to electric shock and fire hazards. Effective protection can be accomplished by implementing active and passive measures: installing Arc-fault Circuit Interrupters (AFCI) or Detection Devices (AFDD), able to detect arcing faults; or wiring the circuits with a grounding protection conductor to involve the ground in every fault. In this way, residual current protective devices (RCDs or GFPDs) protect quickly the series faults with arc, but also without arc. The Ground-Fault-Forced Cables (GFFCs) facilitate the conversion of any kind of fault to a ground fault in all the applications and are particularly recommended for cords and extension cords, internal circuits to grounded equipment, UPS continuity circuits, aircraft circuits, road tunnels, data centers, residential houses and hospitals.

In power systems that comply with best practices, electrical ignition theoretically remains possible only when there is an accident. Generally, if there is a fire, it is not easy to identify its origin because everything is destroyed. In an effort to assist fire investigations, this article suggests a deductive approach in testing possible hypotheses on electrical ignition. It analyzes the different evolutionary scenarios that characterize faults in primary distribution circuits versus branch distribution circuits. As an application, we illustrate a case study of the fire ignition that affected two fabric storage rooms and an adjacent transformer substation.

Miniature film fuse is a key component widely used in electronic systems for circuit protection. In order to meet the demand of high reliability application, higher requirements are raised on the miniature film fuse’s performance of reliability and application adaptability. Based on the characteristics of the fuse, and the actual application requirements of the circuit design, a key method for application verification is designed for the miniature film fuse, to evaluate its applicability and reliability in the high reliability engineering application, to serve as basis for its application in the electronic engineering.

Specific system protection is needed for direct current microgrids in the low voltage range. Model-based analysis of transient events applying system identification and machine learning procedures provides additional knowledge on system topology and components. Using this information, refined model-based fault detection and discrimination methodologies can be set up in addition to the basic functionality of conventional protective devices. Consequential damage and grid sector breakdown can be avoided by fast and selective tripping of suitable switching devices.

Hardware security concerns such as intellectual property (IP) piracy and hardware Trojans have triggered research into circuit protection and malicious logic detection from various design perspectives. In this article, emerging technologies are investigated by leveraging their unique properties for applications in the hardware security domain. Security, for the first time, will be treated as one design metric for emerging nano-architecture. Five example circuit structures including camouflaging gates, polymorphic gates, current/voltage-based circuit protectors, and current-based XOR logic are designed to show the high efficiency of silicon nanowire FETs and graphene SymFET in applications such as circuit protection and IP piracy prevention. Simulation results indicate that highly efficient and secure circuit structures can be achieved via the use of non-CMOS devices.

Electrical and thermal switchable materials are of interest in temperature regulation, circuit protection, sensors and other field. In this paper, functionalized carbon black (CB)/octadecane composites were synthesized for room temperature electrical and thermal switch. With these composites, large contrast ratios of electrical conductivity (EC) and thermal conductivity (TC) are achieved around the phase transition temperature (28–29 °C). The corresponding contrast ratios of EC and TC reach 4.3 × 105 and 3.3 times, respectively. The composites show remarkable stability and durability during the cycling experiments. The mechanisms of good stability and high EC contrast ratio are discussed as well.

Fire destroys all things, so it is not easy to identify its cause. The paper suggests a deductive approach in matching possible hypotheses on electrical ignitions. It analyzes the different evolutions that characterize the ignition in a primary electrical distribution versus to the ignition in a branch distribution. At this aim, the paper illustrates a case study of the ignition of a fire that affected two fabrics storage rooms and a transformers substation that was adjacent.

Aiming at the problem of non - intelligent opening pressure regulation of four-circuit protection valve, a set of automatic adjustment system for four - circuit protection valve opening pressure is designed. The system of the host computer takes LabVIEW software as the development platform, and the programmable logic controller PLC as the next machine, with using COGNEX intelligent camera to accurately locate the four exhaust center coordinates of four-circuit protection valve, coordinating with OPC server communication and NI Assistant camera calibration and other technologies, so that the servo movement system dynamically controls tightening mechanism automatically adjusts the four-circuit protection valve opening pressure. Online authenticating is performed on the two-station hardware experiment platform, and the results show that the system is fast and stable, which also meets the requirements of the industrial positioning accuracy of less than or equal to 0.5mm, and has a 95% success rate of opening pressure adjustment.

Distribution feeder protection could soon be complicated by non-radial flows of real and reactive power available from high penetration distributed generation and potentially from microgrids. Non-directional overcurrent protection may not provide necessary security and sensitivity for faults on remote points of the circuit. Directional supervision is necessary to set overcurrent pickups with adequate sensitivity for remote faults. Setting the directional element by traditional means provides a reliability risk at varying VAR flows within reach of specific types of distributed generation. This paper will demonstrate the limitations of non-directional overcurrent protection and the pitfalls of an improperly configured directional element. A unique solution using directional overcurrent elements further secured by a load encroachment function can solve these problems. This approach has been validated in renewable plant collector circuit protection applications over a wide range of operating conditions.

A robust ESD device for 5V circuit protection was designed and fabricated in a 0.5-µm 5V CDMOS process. It is composed of multi-fingered GCNMOS and ballasting-resistor. The ESD performance of such device with strip layout style is investigated by employing transmission line pulse (TLP) measurement. A double-triggered phenomenon is detected in the multi-fingered GCNMOS with ballasting-resistor. And this device's ESD performance is superior to the traditional multi-fingered GCNMOS for its relatively stronger ESD device robustness, higher HBM rank, build-in secondary protection mechanism, and the holding voltage (Vh) also gets a promotion from 6.9V to 8.5V.

This paper presents a simplified model of arc fault that allows analyzing the dynamic behavior and evaluating the rms value of arcing fault current and the incident energy released by the electric arc. This study confirms previous results carried out in low-voltage and medium-voltage systems in different configurations, where the values of arcing fault current estimated by the simplified model are in accordance with the corresponding values determined by the equations described by IEEE Standard 1584. The dynamic behavior of the electric arc depends on a lot of factors. As improvement, the simplified model allows analyzing and determining basic parameters such as conduction angle, peak value, reduction factor of arc current, and power and energy supporting the understanding of the phenomenon of the arc flash. The behavior of the arc current conduction is predicted by knowledge of the phase angle of fault circuit impedance and the phase angle of the ignition voltage; the reduction factor of arc current is variable depending on whether the conduction is continuous or pulsating.

Overheating is the single biggest cause of failure in switchgear. Modern circuit protection is provided by digital overcurrent relays which are operated by current, not heat so abnormal heating caused by loose connection bolts, ventilation failure or worn contacts is usually left undetected by conventional circuit breakers. This can lead to pre-mature failure of switchgear and also constitutes a potential fire hazard. Thermal imaging can help prevent this but is only valid for that `snapshot' in time. Continuous condition monitoring of the temperature of switchgear can substantially minimise down time of the installation and reduce the risk of fire.

Electrical properties of the laminated SMD-type PTC thermistor for microcircuit protection were investigated as a function of calcination and sintering temperature. BaTiO₃ with Y₂O₃ and MnO₂ were calcined at 1000 to 1150℃ for 2h and the laminated SMDtype PTC thermistor was sintered at 1350 to 1400℃ for 2h in a reduced atmosphere (1% H₂/N₂). Sintered density of the sample was dependent on the calcination and sintering temperature. Electrical properties of the sintered samples were strongly dependent on thedensities of samples. For the samples with density below 4.6 g/㎤, the insulator characteristics were observed, while PTC jump characteristics (R150/R30) were disappeared for the sample with density above 5.05 g/㎤, Optimal PTC characteristics were obtained for the sintered samples with density of 5.05 g/㎥. The laminated SMD-type PTC thermistor prepared by calcination at 1100℃ for 2h and sintering at 1270℃ for 2h showed the room temperature resistivity of 11 Ωㆍcm and PTC jump characteristics of 10 2 order.

As a circuit protection device, failure or abnormal behavior of polymer positive-temperature-coefficient resettable devices can cause damage to circuits. Identification of failure modes and determination of failure causes are necessary to improve the reliability of resettable circuit protection devices and understand their limitations. In this study, a series of experiments was conducted to identify the failure modes of polymer positive-temperature- coefficient resettable circuit protection devices. The causes of failures of a polymer positive-temperature-coefficient resettable circuit protection device were determined by failure analyses, including analysis of the increase in surface temperature using an infrared camera, interconnection analysis using cross-sectioning and environmental scanning electron microscopy, analysis of the microstructures of carbon-black-filled polymer composite, thermal property analysis of the polymer composite, and coefficient of thermal expansion analysis of different parts of the resettable circuit protection device.

As circuit protection devices, failure or abnormal behavior of polymer positive-temperature-coefficient resettable devices can cause damage to circuits. It is necessary to detect anomalies in the resettable circuit protection devices to provide early warning of failure and avoid damage to a circuit. In this paper, a novel anomaly detection method, the cross-validation-based sequential probability ratio test, is developed and applied to the failure precursor parameters of the resettable circuit protection devices to conduct anomaly detection. The cross-validation-based sequential probability ratio test integrates the advantages of both the sequential probability ratio test for in situ anomaly detection and the cross-validation technique for model parameter selection to reduce the probability of false and missed alarms in anomaly detection. The cross-validation-based sequential probability ratio test solves the model parameter selection difficulty of the traditional sequential probability ratio test and improves its performance in anomaly detection.

We investigated the electrical properties the starting material and sintering condition on the laminated PTC thermistor for micro circuit protection. The influences of BaTiO 3 powder with the 0.3 and 0.45 μm size and the electrical characteristics (Ba,Sr)TiO 3 sintered at 1350~1400℃ for 2 h in a reducing atmosphere (1% H 2 /N 2 ). The sintered (Ba,Sr)TiO 3 was increased pore and the grain size was decreased according to increasing Sr additions. In relative permittivity, the phase transition temperature of (Ba,Sr)TiO 3 was decreased for 2.5℃ according to increasing 0.01 mole Sr additions, and the phase transition dose not appeared about 0.3 mole Sr addition. The (Ba,Sr)TiO 3 was show the low resistance from 0.01 mole to 0.05 mole by Sr addition, regardless of sintering temperature. The (Ba,Sr)TiO 3 was show 10 2 jump order at 0.1 and 0.2 mole Sr addition, and PTCR of the sintered (Ba 0.7 Sr 0.3 )TiO 3 does not appeared about 0.3 mole Sr addition, regardless of the sintering temperature and starting material size.

Resettable fuses have been widely used in overcurrent or overtemperature circuit protection designs in computers, automotive circuits, telecommunications equipment, and medical devices. Abnormal behavior of a resettable fuse can damage a circuit. This paper identifies and experimentally assesses the failure precursor parameters of a polymer positive temperature coefficient resettable fuse. It is shown that the degradation of the resettable fuse can be monitored, detected, and predicted based on the monitoring of these precursor parameters.

There are several approaches for ESD protection of integrated circuits. This paper provides practical guidelines to I/O library designers to choose the right methodology for ESD protection of I/O libraries in advanced CMOS technologies. Guidelines are provided predominantly for low-voltage I/O libraries that are commonly used for general purpose interfaces and industrial low-voltage interfaces such as DDR, MLB, USB, etc. Additionally, some general background issues of ESD protection methodologies used in the industry are considered. This paper is focused on HBM and MM ESD protection solutions. Special CDM ESD protection solutions are not considered.

CDM ESD event has become the main ESD reliability concern for integrated-circuits products using nanoscale CMOS technology. A novel CDM ESD protection design, using self-biased current trigger (SBCT) and source pumping, has been proposed and successfully verified in 0.13-μm CMOS technology to achieve 1-kV CDM ESD robustness.

Power supply for electronics is one of the more recent application areas which has been explored for MEMS devices and techniques. Within this field, the most actively researched application has been MEMS power sources, particularly to replace batteries for portable electronic devices such as wireless sensor nodes. In addition, there are possibilities for MEMS devices in circuit protection, and power conversion and conditioning. This paper reviews these applications. More detailed descriptions are presented of work at Imperial College on motion scavenging power sources and MEMS circuit breakers, and examples of work in power applications by other groups are also given. Finally, some possible future directions are discussed.

This paper provides an overview of the potential impacts that electronic-coupled generators, such as those used on distributed generation (DG), will have on the electric grid. First, it will provide a description of how Southern California Edison (SCE) performed short circuit (fault) tests on electronic-coupled generators. In addition, the paper will show how to analyze actual fault test data from electronic-coupled generators such as solar photovoltaic (PV) inverters. Furthermore, it will provide an overview of the potential system impacts that DG may bring to distribution circuit protection, circuit breakers (CBs). Finally, the paper will provide recommendations on how to prevent or mitigate fault impacts from electronic-coupled generators.