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Arc Faults and Electrical Safety
Published in Paul G. Slade, Electrical Contacts, 2017
Since the late 1980s, research on mitigating residential electrical fires produced from electrical arcing faults has led to the development of the first commercially available Arc Fault Circuit Interrupter (AFCIs) in 1999 [5–8]. These circuit protection devices are designed to mitigate the effects of electrical arcing faults that are not detected by ordinary thermal-magnetic (T-M) circuit breakers or other types of circuit protection devices [5–10]. These new circuit protective devices have the potential to reduce property and equipment damage and minimize personnel injury by their ability to sense various types of arcing faults [5–10]. Today, AFCI technology is an actively researched field with many companies and universities pursuing advancements in detection methodology, testing standards, and basic arc physics to advance electrical safety [9, 11–17].
Battery-Backup Grid-Connected Photovoltaic Systems
Published in Roger Messenger, Homayoon “Amir” Abtahi, Photovoltaic Systems Engineering, 2017
Roger Messenger, Homayoon “Amir” Abtahi
There are essentially two types of 120-V circuits in an occupancy. The simplest is when a hot wire and a neutral wire, generally run as a piece of “romex” (Type NM) cable, run from an existing electric panel to a load or, perhaps to as many as ten 120-V outlets connected in parallel. Normally, these circuits are connected to single-pole 15- or 20-A circuit breakers, or, sometimes to fuses. In these cases, the circuits can be transferred to either a separate distribution panel that has been wired for 120 V, or to a circuit breaker in the PV system ac component enclosure. That is, except for one detail. In the 2014 NEC, nearly every circuit in a dwelling unit must be protected by either an arc fault circuit interrupter or a ground fault circuit interrupter. The arc fault circuit interrupter is capable of detecting arcing at current levels below the circuit breaker trip rating and interrupting the circuit. The ground fault circuit interrupter is capable of detecting a difference of as little as 5 mA between the hot and neutral conductors of a circuit and interrupting the circuit if such a fault should occur.
Principal safety precautions
Published in John M. Madden, Electrical Safety and the Law, 2017
Not all arcs are caused by earth faults. Phase-to-phase or phase-to-neutral arc faults that have the potential to initiate a fire will not be detected by RCDs, and the fault current may be too low to operate overcurrent protection such as a fuse or circuit breaker. One option that may be considered is that of the arc fault detection device (AFDD), also known as an arc fault circuit interrupter. This is a unit about the size of a standard 2-pole disconnector that analyses voltage and current waveforms and, when the waveforms have the characteristics associated with the presence of an arc fault, will interrupt the affected circuit. Such devices are widely used in the United States and other countries, and although their use is not currently a requirement of British standards, it is likely that it will become so in the coming years.
Simplified Active Power Regulation Scheme for Grid Connected Solar Photovoltaic based Micro-Inverter
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Ganesh Moorthy Jagadeesan, Raja Pitchaimuthu, Moorthi Sridharan, Venkata Kirthiga Murali
With the above-mentioned points, this work has been carried out to explore the possibility and implementation of APR schemes for such a single-stage micro-inverter-based solar photovoltaic (SPV) system. Nowadays, module-integrated type grid-tied PV micro-inverters are finding good scope in the market compared to existing string inverters due to their unique characteristics such as the elimination of (DC) arc-fault circuit interrupter, plug and play, no mismatch losses, and individual MPPT. Due to high voltage gain, isolation, compact design, and high-frequency operation, the flyback type micro-inverter topologies are found to be promising. In this work, based on the command from the micro-grid operator or intelligent control devices, the SPV system will switch its operation between MPPT mode and APR mode. The literatures clearly show that there is no trace of the APR scheme implemented to control a single-stage micro-inverter-based grid connected SPV system, which motivated the authors to design and test the APR scheme for a single-stage micro-inverter in this paper. There are various configurations proposed for a SPV-based grid-connected single-stage micro-inverter (Kan et al. 2021; Shawky, Takeshita, and Sayed 2020). Among such configurations, the topology proposed in Hu et al. (2013) has been considered due to the following reasons: high voltage gain, isolation, compact design, and high-frequency operation, and pulsated power decoupling capability.