Surge Protection Research Articles

Computer-aided Optical Plasma Postprocessing Applied on Model Spark Gaps

Spark gaps are used as surge protective devices (SPD class 1) for low voltage grids protection against surge currents and overvoltages. For practical research of the narrow gap plasma of spark gaps, high-speed camera recordings are used in modified transparent test models. In this test setup, current densities of 1010 A/m2 are generated. In order to optimize and automate the evaluation process of camera recordings, an image analysis tool is developed further in this contribution. After basic image improvement and segmentation, this research optimizes a detection algorithm for plasma location and distribution. As a result, the known plasma distribution gives access to significantly more information about the plasma behaviour and the spatial distribution of radiation.

A simplified transient model of surge protective devices employing varistors

This work provides a simplified transient model for low-voltage DIN rail surge protective devices (SPDs), accounting for their resistive, inductive, and capacitive behavior. The time-domain modeling approach is based on impulse current and sinusoidal voltage experiments. The lumped-circuit model is implemented in the ATP-EMTP environment and yields results in satisfactory agreement with the experimentally derived residual voltage and energy absorption of commercially available DIN rail SPDs for single- and three-phase installations. The proposed model can be used for evaluating the protection level and maximum residual voltage of SPDs under standard and non-standard surge currents and can be an effective tool employed in insulation coordination studies of power systems.

Varistor coupling method and recommendation parameters for combination wave test

AbstractVaristor coupling is recommended by International Telecommunication Union in combination wave test waveforms of surge protective devices (SPD), although the varistor coupling method and recommendation parameters for the combination wave test are not well understood. The waveform influencing characteristics introduced by varistor coupling are studied in detail in this paper. Low‐voltage varistors, with maximum operating voltages ranging from 130 to 750 V, are adopted here in the OrCAD/PSpice environment to analyze the influence of varistor coupling on the output characteristic of the combination wave generator (CWG) in test levels of 0 to 20 kV. Simulation results show that, owing to varistor coupling, the reverse oscillation phenomena will arise in the open‐circuit voltages (OCVs). Also owing to varistor coupling, compared with those generated directly by a CWG, the peak value, the front time, and the tail time for both OCV and short‐circuit current will decrease, whereas the virtual impedance will increase. Moreover, the lower the test level, or the higher the maximum operating voltage of the varistor, the more serious this effect. Experiments have also been conducted here, and our simulation results are found to match the experimental ones well. It seems that, compared with the conventional capacitor coupling, the range of the voltage of power supply networks and the levels of combination wave test by varistor coupling have to be limited to a great extent. Varistor coupling for combination wave test of SPD should be only used in special cases and special test levels where there are no strict waveform limitations.

The influence of conventional sintering on the microstructure and electrical properties of ZnO-based varistor

Zinc oxide varistors are frequently utilized as surge protection devices in power systems. ZnO based varistors' electrical properties depend on their microstructure, which may be altered by sintering. In this paper, we look at how conventional sintering affects the microstructure and electrical characteristics of ZnO-semiconductor varistors. ZnO-based varistors were made using a traditional solid-state reaction process and sintered for 2 hours at varying temperatures (1100 °C, 1200 °C, and 1300 °C). Scanning electron microscopy and X-ray diffraction were used to examine the microstructure and phase composition. A conventional test procedure was used to measure the electrical parameters of the varistors, such as the breakdown voltage, leakage current, and nonlinear coefficient. Traditional sintering has a considerable impact on microstructure and electrical properties.

Mitigation of Lightning-Induced Transient Effects on a Hybrid Photovoltaic–Wind System Based on Lightning Protection Standards

Installing surge protection devices in a hybrid photovoltaic (PV)–wind system is essential to guarantee the survival of the system’s components. If the surge arresters are connected without taking into account the recommendations given by standards, the equipment to be protected might be damaged despite the energy coordination of the arresters. In this study, nonlinear surge protective devices (SPDs) are designed for a multi-MW hybrid system based on lightning protection standards with optimised threat level ratings to investigate the mitigation of lightning transients to an acceptable level. The system is implemented using Power System Computer-Aided Design for Electromagnetic Transients including Direct Current (PSCAD/EMTDC) software. It comprises a 2 MW PV farm, a 2 MW wind farm, and a backup energy storage system (ESS), which are all connected to a 132 kV grid via a step-up transformer and a transmission line. The results were obtained at critical system nodes for two standard lightning current surges, i.e., 1/10 µs and 10/350 µs, considering two lightning strike point scenarios with and without a lightning protection system (LPS). The simulation results showed that the connected SPDs could successfully limit the transient overvoltage in the system to an acceptable level. The analysis in this work is crucial for designing, operating, and maintaining a hybrid PV–wind system. It can help to find the potential vulnerability areas within such a system and implement appropriate protection measures since there is no available lightning standard for such systems. Additionally, it assists the system operators in increasing the uptime and dependability of their RE systems, limiting expensive downtime and environmental effects while optimising energy output. Based on the results obtained, recommendations were made for lightning protection developers.

Control Development and Fault Current Commutation Test for the EDISON Hybrid Circuit Breaker

The DC circuit breaker is an indispensable building block for DC network systems. Hybrid circuit breakers that combine mechanical and solid-state switches have more potential to be utilized in DC distribution networks because of their lower conduction losses and fast interrupt speed. The efficient energy DC interrupter with surge protection (EDISON) removes any solid-state circuit in the main current path, thereby substantially reducing the conduction losses during normal operations. However, it requires a dedicated control with fast dynamics because any false triggering of the mechanical switch or solid-state switches of the breaker would lead to a commutation failure and a potential unquenchable arc. This paper proposes a finite-state-machine (FSM) based control scheme that guarantees an accurate and fast control response during a fault event. Due to this fast response requirement, a dual-core-CPU-based control architecture is applied featuring parallel taskings and negligible communication delays between the two cores. Furthermore, a control-law-accelerator (CLA) is employed to further reduce the latency of the program execution by 33%. The controller hardware-in-the-loop (CHIL) model of the EDISON breaker is implemented in OPAL-RT to verify the control scheme and de-risk the prototype test. A fifth-order RLC network is developed to characterize the mechanical switch behavior such that the hybrid circuit model can be simulated in the CHIL solely by circuit components. Finally, the proposed control scheme is implemented and validated in a prototype test with a 3 kA interrupting current and a 60 A/μs current commutation rate.

Abatacept to induce remission of peanut allergy during oral immunotherapy (ATARI): protocol for a phase 2a randomized controlled trial.

While oral immunotherapy (OIT) has been shown to promote the remission of mild peanut allergy in young children, there is still an unmet need for a disease-modifying intervention for older patients and those with severe diseases. In mice models, abatacept, a cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) immunoglobulin fusion protein, has been shown to promote immune tolerance to food when used as an adjuvant to allergen immunotherapy. The goal of this study is to explore the potential efficacy of abatacept in promoting immune tolerance to food allergens during OIT in humans. In this phase 2a proof-of-concept study (NCT04872218), 14 peanut-allergic participants aged from 14 to 55 years will be randomized at a 1:1 ratio to abatacept vs. placebo for the first 24 weeks of a peanut OIT treatment (target maintenance dose of 300 mg peanut protein). The primary outcome will be the suppression of the OIT-induced surge in peanut-specific IgE/total IgE at 24 weeks, relative to the baseline. Sustained unresponsiveness will be assessed as a secondary outcome starting at 36 weeks by observing incremental periods of peanut avoidance followed by oral food challenges. This is the first study assessing the use of abatacept as an adjuvant to allergen immunotherapy in humans. As observed in preclinical studies, the ability of abatacept to modulate the peanut-specific immune response during OIT will serve as a proxy outcome for the development of clinical tolerance, given the small sample size. The study will also test a new patient-oriented approach to sustained tolerance testing in randomized controlled trials.

Influence of Spark Gap Parameters on the Strength of the Surge Protection Device and the Method of Its Selection

The paper aims to analyze the factors affecting the parameters of surge protection devices with a spark gap and assess the impact of changing these parameters on the level of overhead line strength. For this purpose, this paper contains the results of tests that show the assessment of the impact of changing the spark gap parameters on the voltage–time characteristics of selected protection devices in the range of negative and positive polarity. The paper presents how the change in the parameters of the component element of the surge protection device, which is the spark gap, may affect the selection of the line surge protection method. In addition, the paper presents a method of assessing the strength of an overhead line, taking into account the case of installing surge protection devices at the insulators. The implementation of these tests supports further activities aimed at the actual values of parameters affecting the strength of overhead lines.

The Current Generation Mechanism in the Earth Lines of a Building in TT System Struck Directly by Lightning

Surge protective devices (SPDs) are installed between the neutral and earth lines at the power substation in a TT system to protect the equipment in a building struck directly by lightning. In this case, when operating the SPD, the wiring system of the low-voltage distribution line is a TN system. Using this system, our previous study clarified that the overvoltage generated in the distribution board on each floor was caused by the loop impedance of earth wiring connected to the distribution board. In this article, we elucidated the electromagnetic generation mechanism of the current flowing in the protective earth line that formed the wiring loop.

Lightning Surge Overvoltage Protection for Low-Voltage Equipment Placed Outdoors in TT System

When a TT system is used for earthing a low-voltage distribution line, the conductive enclosure of the equipment is grounded separately from the system ground for the power line. In such a case, lightning protection depends on the installation of surge protective devices (SPD) on the equipment side. However, in newer systems, a protective earth (PE) line is wired from the power substation for stable operation and connected to the PE line in the outdoor equipment. In this case, the SPD of the distribution board can suppress the overvoltage on the equipment side. In this article, the overvoltage generated between the power and grounded PE lines of the equipment using a vinyl-insulated vinyl-sheathed flat-type cable for a low-voltage distribution line was examined using transient circuit analysis. Then, we demonstrated countermeasures to achieve electric shock and lightning overvoltage protection.

Design of a Current-Transformer Based Inductive Coupler for Power-Line Communications

In this paper, the design of a current-transformer based inductive coupler for power-line communications is documented. A worst-case design is presented in a step-by-step fashion and experimentally confirmed by doing verification measurements in the laboratory as well as live, 240-V tests in a controlled environment. Although field deployment of inductive couplers usually relies on parasitic capacitance and/or surge protection capacitors to complete the current loop, in this controlled experimental setup various discrete loop capacitors were utilized to characterize the impact on transmission. A band-pass filtering response was achieved without any external filter circuitry, as internal coupler parasitic parameters were utilized for this. For the single-coupler laboratory measurements, both the lower and upper cut-off point results were approximately within 10% of predicted values. These results are quite encouraging, seeing that coupler core permeability is specified with a ± 20% tolerance. Live tests showed that (i) cable length (series inductance) impacts on the upper cut-off point of the system passband, while (ii) loop capacitance affects the lower cut-off point of the system passband.

An Enhanced Anti-surge Circuit for New Energy Vehicle Electronics System

This paper presents an input surge protection circuit for automotive electronics systems with an adjustable overvoltage protection threshold suitable for high input voltage applications. Compared with the conventional overvoltage protection circuit, it boasts a new high-voltage bandgap reference circuit design without pre-regulation, which takes up less space and can be used on a limited PCB board, expanding the practical application range of the chip. The gate protection circuit can monitor the gate-source voltage of the power MOS in real-time and control the charge pump’s operating mode to improve the system’s safety. The design and simulation of the circuit adopt the 0.18 μm 5V/25V BCD process. The simulation results show that the bandgap reference voltage varies by only 0.38 mV in the input voltage range of 3.5 V-25 V. The quiescent current is 146 uA at 5 V supply voltage. The power MOS can be turned on quickly within 50 us. The overvoltage response time is 599 ns, permitting the circuit to be shut down when a surge occurs.

Lightning protection technology and grounding technology of transmission tower shared equipment

For the power transmission tower shared equipment, there are strong current wireless interference and complex grounding environment, which leads to problems such as unstable operation of the shared equipment. Based on the multi-grade surge protector and new grounding technology, through the impulse experiments, we apply simulated lightning current generated from combined wave generator (1.2/50 μs, 8/20 μs) on the modle, and an oscilloscope is used to collect residual voltage and current data to calculate the absorbed energy of the grounding unit. It is concluded that when the impulse voltage is between 300 V and 3500 V, as the impulse voltage increases, after passing through the multi-grade surge protector and grounding unit, the residual voltage and current value continue to increase, and the residual voltage value is 23.4 V–29.6 V increases linearly, and the increase is small; the internal resistance of the grounding unit decreases with the increase of the impulse voltage. The energy absorbed by the grounding unit is positively correlated with the impulse voltage and negatively correlated with the internal resistance, and its energy absorption percentage decays linearly. The multi-grade surge protector can effectively clamp the residual voltage value within a safe value, and its discharge effect is better than that of the traditional protection mode. It provides a theoretical basis and data reference for the lightning protection and anti-interference projects of the actual transmission tower sharing equipment, and has certain practical value.

Multifunctional bypass valve for water management and surge protection in a proton-exchange membrane fuel cell supply-air system

A multifunctional valve for air supply was placed downstream of the compressor in a fuel cell system to manage cathode air characteristics under different load changes and configurations. The advantages of using the four-way valve, with different ports for cathode flow, throttling, and bypassing, were analyzed through modeling and simulation. The model focused on the air supply system, which included a centrifugal compressor, intercooler, membrane humidifier, valve, and mixer. The simulation demonstrated that placing the valve right after the compressor was more effective in controlling the compressor surge than a traditional back pressure valve. During compressor surge, opening the throttling port at 18° could suppress the surge and stabilize the cathode flow. The balance between surge protection and stack performance under transient conditions was also discussed, and an optimal valve opening for throttle flow was presented. Furthermore, bypassing the humidifier by 20% of the supply air reduced the cathode inlet relative humidity by the same percentage, contributing to water management in the stack, particularly under flooding conditions.

Surge protective device failure caused by triggered lightning continuing current and M component

Surge protective device failure caused by triggered lightning continuing current and M component

SCR-Based Bidirectional Circuit Breaker for DC System Protection With Soft Reclosing Capability

The emergence of power electronics has lead to a paradigm shift towards dc grids, which are widely recognized to provide better performance and efficiency. However, fault isolation is one of the prime challenges of dc grids due to the absence of current zero-crossing. With this motivation, this paper introduces a novel silicon-controlled-rectifier-based bidirectional dc solid-state circuit breaker. In addition to its ability to isolate the faulty section, the proposed topology can also provide soft reclosing capability, which aids in reducing repetitive voltage and current stress on the breaker and current feeding components. Moreover, the heat loss by the surge suppression devices during reclosing is negligible. Equations are derived to analyse the effect of component values on various circuit-level considerations. Simulation and scaled-down experimental results are presented to verify the operation of the breaker under various operating conditions.

Permeance Based Design and Analysis of Supercapacitor Assisted Surge Absorber for Magnetic Component Selection

AbstractSupercapacitor assisted surge absorber (SCASA) technique is a unique and commercially useful design approach for surge protector devices. SCASA topology is based on the combination of a coupled inductor which partly acts as a transformer, and a supercapacitor sub-circuit. In developing the first commercial product, the research team had to optimize the selection of the magnetic core, based on empirical approaches and industry price constraints. This paper presents a permeance-based design and analytical approach to SCASA, with the topological details of its first successful implementation. While existing SCASA topology performs satisfactorily, this research elucidates design techniques to improve surge absorption by 60% and reduce load clamping by 10% based on high-performance prototypes developed using High-Flux and X-Flux toroids. The test results presented in this research are validated by experimental work carried out in a high-voltage surge laboratory using Noiseken LSS-6230 lightning surge simulator adhering to IEEE C62.41/IEC 61000-4-5 standards. Surge immunity of SCASA prototypes was evaluated using international test procedures of UL-1449 3rd edition standard. Index TermsMagnetic permeance, SCASA, Supercapacitor, Surge protection, Transient absorption

Review on mangrove restoration: Re-greening the sea coast

Mangroves are important coastal resources that can provide exceptional ecosystem benefits. Several of its ecosystem functions, including sediment buildup, carbon sequestration, and storm surge protection, are being recognized as practical tools for climate change adaptation and mitigation. Its unique capacity to endure extreme environmental circumstances makes them; in particular, the only viable option for ecosystem-based adaptation in exposed coastal locations. Mangroves are among the most severely damaged tropical ecosystems, and they are continuing to disappear as a result of increased human activity. Especially in the Asia-Pacific region, where they exist in the form of complex socio-ecological systems, mangroves remain heavily threatened due to numerous anthropogenic activities. Mangroves are under grave danger; hence it is imperative that prompt steps be taken to methodically conserve and restore their ecosystems. The Asia-Pacific region is the location of nearly half of the existing mangroves, scattered over some of the poorest and post-conflict states. Dependence on traditional sources of income and the recent trend of coastal development have had a negative impact on the region's mangrove sustainability. Lacks of supportive policies and mangrove conversion to non-forest uses has been further fueled by insufficient institutional intervention. Nevertheless, in recent years, participatory, multi stake holder-based approaches for mangrove conservation and/or restoration have gained immense popularity in the region of Asia pacific. Participatory management which exemplifies an ameliorative approach can also support sustainable development, community empowerment, and social inclusion. Despite its asserted superiority, a number of new sustainability challenges need to be carefully examined and reconciled due to conflicting results of earlier experiences.

CAPACITY EXPANSION AND INSTALLATION OF SURGE PROTECTION DEVICE IN SOLAR POWER PLANT SYSTEM FOR HYDROPONICS FARMER

Community service has been carried out in Pasuruan, Eastern Java. A hydroponics farming system, run by a group of farmers in Kecamatan Gempol, consumes electric energy provided by a 900 Wp solar power system. The power plant is equipped with two batteries, 12 V 100 Ah, with a Depth of Discharge (DoD) of 80% each, which enables the power system to store the energy of 1920 Wh as a reserve. According to the farmer’s report, one of the essential components in the solar power system was damaged twice due to lightning strikes at an adjacent time. Also, the hydroponics system is unable to run all night continuously due to the insufficient capacity of the storage system. Therefore, surge protection devices (SPD) are installed in the solar power plant system to protect crucial components from damage caused by lightning strikes. Furthermore, this activity adds two more batteries to the system that double the energy reserve to extend the operating hours of hydroponics electrical equipment when sunlight is unavailable. The work also created a new hydroponics platform with 126 holes as a part of capacity expansion to meet the market demands. Extra protection against insects is also provided by shielding the hydroponics platforms close to the bushes with the insect net.

Analysis of the Integrated Effect of Temporary Overvoltages, PV Transformer Connection and Overcurrent Protection in Hybrid PV-Wind Energy System

The integration of solar and wind energy in hybrid PV/Wind energy systems (HPWES) have allowed it to be more reliable renewable energy source. However, the overvoltage protection for HPWES is scarcely covered in literature. To fill this gap, an investigative analysis of the effect of temporary overvoltages (TOVs) in HPWES is presented in this paper. Sources of TOV considered were ground faults and load rejection events. The HPWES was simulated and tested for TOVs under different fault conditions. The results showed that the TOV response was dependent on three more elements; overcurrent protection relays (OCRs), surge protective devices (SPDs) and the type of the PV transformer connection. The analysis showed that an interactive effect between these three elements after the occurrence of TOVs. This interactive effect has affected the tripping time of the OCRs which in turn affected the TOV duration and the energy absorbed by SPDs. It was concluded that the impact of the type of transformer connection and OCR tripping settings upon SPD could be critical that in some cases could lead to SPD failure. Conclusions are presented to the designers of HPWES to consider them during the design phase to overcome possible failures of SPDs.