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The good mechanical characteristics of circuit breakers are essential to ensuring their safe and stable operation. The characteristic signals at the points of initial opening and closing contain abundant information about the mechanical–time characteristics of the circuit breaker. Existing online measurement methods for circuit breaker mechanical–time characteristics typically rely on monitoring the secondary current signals of the opening and closing coils, or the signals such as vibration, pressure, and angular displacement that are generated during the opening and closing of moving and stationary contacts. Unlike these conventional approaches, this paper proposes an online measurement method for circuit breaker mechanical–time characteristics based on feature extraction from transient voltage and current signals in the primary circuit. By extracting features from the transient voltage and current signals in the primary circuit, this method obtains mechanical–time characteristics such as the points of initial opening and closing. This method is convenient and stable, enabling the online detection of the mechanical characteristics of the circuit breaker. Finally, a comparison and analysis of the online measurement results with the offline measurement results were conducted. The analysis shows that the calculation error of the opening and closing times is within 0.2 ms. This online detection method has a high measurement accuracy and provides a new approach for the online measurement of the mechanical characteristics of circuit breakers. [ABSTRACT FROM AUTHOR]

Among all circuit breaker faults, mechanical failures account for a considerable proportion, and online monitoring of their mechanical characteristics is of great practical significance. The opening and closing time is a very important feature of the mechanical characteristics of the circuit breaker. Online monitoring of the opening and closing time of the circuit breaker has always been the focus and difficulty of the intelligent technology of switchgear. In this paper, for a 10 kV spring energy storage vacuum circuit breaker, transient voltage and current signals are innovatively used to calibrate the opening time, breaking time, and closing time, and an online monitoring method for the opening and closing time of a vacuum circuit breaker based on transient electrical signals is proposed. An online monitoring platform was built and a multi-group closing test was carried out to simulate the power plant environment. The opening and closing time samples of a spring energy storage vacuum circuit breaker were measured and compared with the measurement results of the mechanical properties tester. The comparison results show that this method has good stability, and the calculation error is controlled within 1% after self-calibration, which provides a new idea for the online monitoring research of the mechanical characteristics of spring energy storage vacuum circuit breakers. [ABSTRACT FROM AUTHOR]

High voltage switchgear is an essential element for the transformation of energy systems towards sustainable and low carbon footprint technologies by electrification of society and industry. This contribution highlights some important research and technology trends in high voltage (HV) switchgear development for reaching greener and smarter electricity transmission systems. In AC transmission, the focus is on the replacement of SF6, which is a strong greenhouse gas, in HV switchgear. Condition assessment is an important field within the “digitalization” of transmission systems to ensure reliability at reduced costs. Research activities and trends in these fields are discussed. Furthermore, HVDC transmission systems will be important for the future electricity system. As more point‐to‐point links are built, and as the need for HVDC transmission increases with a growing integration of renewables and rising demand for electricity, more complex multi‐terminal HVDC grid topologies appear. Activities in this field are also presented with a focus on HVDC circuit‐breakers and gas‐insulated HVDC systems, which have been emerging in the last years. © 2024 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

We model the dynamics of an asset price in the presence of a circuit breaker. A circuit breaker is a trading halt imposed by the exchange after the price drops below (or rises above) a pre-specified value within a trading session. The investors' anticipation of the probability of a halt feedbacks on the price process. In a general stochastic financial framework, this leads to coupled integral and stochastic differential equations. With first-order analytical solutions and numerical treatment, the theory predicts an increased price volatility prior to the trigger point, as has been reported in the empirical literature. We show that the sole existence of a circuit breaker leads to the adverse effect of attracting the price to the circuit breaker level (known as the ‘magnet effect’). We then propose first steps towards a more robust design of circuit breakers. In particular, we show that a trading halt that is conditioned on a pre-specified volatility level, instead of price level, mitigates the negative side effects of increased volatility. The methodology proposed in this article serves as starting point for the design of more resilient circuit breaker mechanisms. [ABSTRACT FROM AUTHOR]

The plum blossom contact spring of the circuit breaker in the power supply line of an ultra-supercritical unit broke after about 50,000 h of operation. In this study, various experimental techniques such as macroscopic examination of morphology, metallographic analysis, chemical composition analysis, scanning electron microscopy and hardness analysis were used to analyze the causes and types of fracture of the plum blossom contact spring. The results indicate that the structural unevenness of the contact spring led to an uneven distribution of tightening pressure on the moving contact, resulting in localized overheating and consequent stress relaxation. This is identified as the main cause of the spring breakage. [ABSTRACT FROM AUTHOR]

Neural-networks (NNs) for the current feature analysis bring novel electrical safety functions in smart circuit breakers (CBs), especially for preventing the fire hazard from electric vehicle/bike battery charging. In this work, the edge artificial intelligence (AI) solutions for the electrical anomaly detection were designed and demonstrated based on the process-in-memory (PIM) AI chip. The ultra-low power and high-performance character of PIM AI chips enable the edge solution to embed in the limited space inside the circuit breaker and to detect improper battery charging at millisecond latency. [ABSTRACT FROM AUTHOR]

Abstract The purpose of this study is to provide data for the best possible circuit breaker allocation in power grids with HVDC transmission while taking circuit breaker failure into account. The lack of a suitable selection of HVDC circuit breakers is one of the primary obstacles to establishing an appropriate protection system for HVDC transmission. This research focuses on finding the optimal circuit breaker allocation strategy with respect to the transient response of the system, especially when the grid operator is using existing circuit breakers, rather than on the necessary steps to improve the technology of circuit breakers. Case studies are simulated using PSCAD/EMTDC in order to verify the transient response of the transmission system corresponding to the allocation of circuit breakers and the circumstance of circuit breaker failure. It is crucial to remember that there isn’t a strategy that is always the best. Consequently, a detailed analysis of the suggested approach is required, taking into account the benefits and drawbacks from the standpoints of fault clearing, power system planning, and operational factors. In the context of HVDC transmission, the authors hope that their research will spark and start conversations about circuit breaker allocation strategies.

The purpose of this study is to provide data for the best possible circuit breaker allocation in power grids with HVDC transmission while taking circuit breaker failure into account. The lack of a suitable selection of HVDC circuit breakers is one of the primary obstacles to establishing an appropriate protection system for HVDC transmission. This research focuses on finding the optimal circuit breaker allocation strategy with respect to the transient response of the system, especially when the grid operator is using existing circuit breakers, rather than on the necessary steps to improve the technology of circuit breakers. Case studies are simulated using PSCAD/EMTDC in order to verify the transient response of the transmission system corresponding to the allocation of circuit breakers and the circumstance of circuit breaker failure. It is crucial to remember that there isn't a strategy that is always the best. Consequently, a detailed analysis of the suggested approach is required, taking into account the benefits and drawbacks from the standpoints of fault clearing, power system planning, and operational factors. In the context of HVDC transmission, the authors hope that their research will spark and start conversations about circuit breaker allocation strategies. [ABSTRACT FROM AUTHOR]

Electrical arc fault detector development requires many tests to develop and validate detection algorithms. The use of artificial intelligence or mathematical transformation requires the use of consequential datasets of current signatures corresponding to as many different situations as possible. In addition, one of the main drawbacks is that these experiments take a great deal of time and are often laborious in the laboratory. To overcome these limitations, a virtual test bench based on the modeling of a modular 230 VAC electrical circuit has been developed. The simulated network is composed of different home appliances (resistor, vacuum cleaner, dimmer, etc.) and its configurations are those of single and combined loads. The fault modeled is an electric arc, modeled by active diode switching, which can be inserted at any point of the circuit. This arc model takes into account the random variations in the restrike and arc voltage. All the appliance models are validated by comparing the frequential (harmonic distortion) and temporal (agreement index) signatures of the measured currents in real situations to those obtained by modeling. The results obtained using the model and experiment network show that the current signatures are comparable in both cases. Further, two detection algorithms are tested on those current signatures obtained by the modeling and experimentation. The results are comparable and provide identical detection thresholds. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Measurement Science & Instrumentation is the property of Journal of Measurement Science & Instrumentation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article describes the development of current sensors used in DCU-type high-speed circuit breakers. DCU-type circuit breakers use the principle of turning off a constant short-circuit current by means of countercurrent. The article presents a new current sensor design called PIKh, which uses Hall sensors to measure current and determine its direction. PIKh sensors allow parallel operation of high-speed circuit breakers during the "parking" operation. The article includes the algorithm and principle of operation of the PIKh sensor. The proposed solution was verified on an electric traction vehicle. [ABSTRACT FROM AUTHOR]

A reliable and cost-effective mechanical direct current circuit breaker (DCCB) is a promising solution for DC interruption. However, the typical mechanical DCCB has difficulty in interrupting a rated current, because the high oscillating current superimposed on the rated current generates a steep current slope at current zero-crossing (CZC) points, which makes it difficult for the vacuum interrupter to extinguish the arc. The objective of this paper is to present a novel DCCB topology with a gradually increasing counter-current. It utilizes a full-controlled converter, a semi-controlled full bridge, and an LC oscillation branch to generate a gradually increasing counter-current, which is superimposed on any fault current and generates a smooth current slope at CZC points. The proposed DCCB topology is modeled with PSCAD, and the current slope and the initial transient interruption voltage (ITIV) at CZC are analyzed and compared with the typical mechanical DCCB. The results indicate that the current slope at CZC decreases by 57–84% in full-range current interruptions, and the ITIV can be reduced by the same extent. Additionally, the performance of the proposed DCCB is evaluated in a four-terminal HVDC system. A cost and performance comparison is conducted among the main topologies. The obtained results show that the proposed DCCB is a reliable solution for the multi-terminal HVDC system. [ABSTRACT FROM AUTHOR]

Microservice architecture is widely used in the development of distributed applications. Many problems present at the beginning of using this approach have already been solved. However, one of the fundamental problems that seriously affects the system's fault tolerance remains unsolved. This fundamental problem is known as guaranteed delivery of messages between services. The article analyzed standard approaches to solving this problem. Based on the analysis, the Circuit Breaker pattern was isolated, and its modification was carried out, which reduced the delay in the transition between states and, accordingly, the sending of messages by the service. The efficiency of the proposed modification has been confirmed experimentally. The result of the modification is presented in the form of a quick configuration for Spring Boot. [ABSTRACT FROM AUTHOR]

Microservice architecture is widely used in the development of distributed applications. Many problems present at the beginning of using this approach have already been solved. However, one of the fundamental problems that seriously affects the system’s fault tolerance remains unsolved. This fundamental problem is known as guaranteed delivery of messages between services. The article analyzed standard approaches to solving this problem. Based on the analysis, the Circuit Breaker pattern was isolated, and its modification was carried out, which reduced the delay in the transition between states and, accordingly, the sending of messages by the service. The efficiency of the proposed modification has been confirmed experimentally. The result of the modification is presented in the form of a quick configuration for Spring Boot. [ABSTRACT FROM AUTHOR]

The article presents the classification of fuses, breakers, circuit breakers and packet switches. The laws of change of probabilistic reliability characteristics of the studied devices, as well as low-voltage cable lines are determined. Types of functions of change of basic reliability parameters are determined and corresponding graphical dependences are shown. The comparison of the obtained results of the values of probability of failure-free operation time with the requirements of GOST and passport data is carried out. The investigated probabilistic parameters of lowvoltage devices and cable lines are checked for compliance with the accepted law of distribution of random variables.

Este artigo tem por objetivo identificar os setores da economia que mais se sobressaíram em meio à pandemia da Covid-19 de 2020, doença causada pelo vírus Sars-Cov-2. Foi realizada análise da variação dos preços das ações das companhias listadas na bolsa de valores de São Paulo, a B3. A pesquisa abordou 193 empresas no período de janeiro de 2016 até dezembro de 2020 e selecionados os segmentos com maior número de empresas que obtiveram as maiores valorizações. O período inicial da análise deste trabalho foi determinado com o intuito de que se tivesse um amplo período, anos antes da pandemia, a fim de verificar a variação do mercado. As análises das variações se deram a partir de um material extraído da própria B3 e consolidado por setor e subsetor, utilizando a rentabilidade das cotações. Ao final, foi possível identificar que no segmento de Materiais Básicos, se sobressaiu dentre todos os demais analisados no período indicado com uma variação positiva de 159,51%, além de uma variação positiva de 50,21% entre o segundo trimestre de 2020 e o quarto trimestre de 2020. Outra importante constatação foi a apresentação da variação positiva do subsetor Agropecuária, sendo o único que obteve um resultado positivo durante o anúncio de situação pandêmica no mundo, com uma variação positiva de 6,11% entre o primeiro trimestre de 2020 e segundo trimestre de 2020.

This paper proposes a shortcoming distance finder model for an underground power link utilizing an Arduino Uno microcontroller. The utilization of underground links presents an issue of distinguishing the shortcoming area and the distance of the link issue as it isn't accessible to see as in the event of an above-ground link. Hence, the underground link shortcoming distance finder is created to distinguish the specific shortcoming area and the distance of the underground link issue from the base station in kilometers. The framework will recognize the blamed link underground and will send the data to the control room by utilizing IoT cloud. A 16x2 LCD display is associated with the microcontroller to show the data. In the event of a shortcoming, the voltage across series resistors changes accordingly, which is then fed to a microcontroller ADC pin to foster accurate digital information to a programmed Arduino microcontroller that further displays the exact shortcoming area from the base station in kilometers. The same data will be updated on the IoT cloud. Incidences of underground link deficiencies in the delivery and power transmission framework are inevitable due to several reasons; thus, a rapid correction and, therefore, automatic shortcoming location are utilized to minimize the time to rectify flaws to make the framework reliable by identifying weak areas quickly, resulting in reduced restoration time and interruption. Proper shortcoming finding and identifying approaches are needed to reduce the intervention time issue and improve reliability [ABSTRACT FROM AUTHOR]

The incorrect operation of protective relays and circuit breakers will significantly compromise the safety and stability of power systems. To promptly detect the faults of the relay protection system and the circuit breakers in time and to ensure the operational reliability of these protective devices, this paper proposes a fault tracing method for a relay protection system–circuit breaker based on improved Random Forest. Firstly, an analysis is conducted to identify the causes of incorrect operation of the protective relay and the circuit breaker. The fault types and corresponding alarm messages for the relay protection system and the circuit breaker are categorized, and the alarm feature set is constructed. Then, the Random Forest is improved and trained to develop the fault tracking model. Finally, the operation evaluation process is developed to determine the incorrect operations of the protective relay and the circuit breaker, and the fault tracking model and fault tracking process are then employed to locate the faults of the relay protection system and the circuit breaker. The experimental results demonstrate the method's capability to accurately track faults in the relay protection system and the circuit breaker, thereby assisting operation and maintenance personnel in troubleshooting and highlighting its promising practical potential. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Fatec Zona Sul (REFAS) is the property of Revista Fatec Zona Sul (REFAS) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To attain current limitation in low voltage circuit breaker (LVCB) apparatus, the approach involves elevating the arc voltage. This improvement is realised primarily in the arc chamber's splitter plates because of the higher drop voltages at the anode and cathode sheath areas. One of the most crucial ways to better describe arc behaviour in LVCB is to account for voltage in the vicinity of the electrodes. To reduce the current, LVCB works by raising the arc voltage. Voltage is raised in several ways, including increase in losses, elongating the arc, and multiplying the splitter plates. The aim of this research is to present readers with an additional technique for analysing electric arcs in moulded case circuit breaker (MCCB) which is one of the types of low voltage circuit breakers which is used to prevent overload and short circuit in electrical systems. 2-D model of MCCB with splitter plate has been developed and simulated using ANSYS software. Simulation results with the effect of increase in the number of Splitter plates considering blow-out coil voltage in arc chamber has been discussed. Modelling and simulation technologies provide the mechanism through which this understanding may be attained.

In a battery energy storage system (BESS), short-current protection is critical and need to be designed carefully to enhance the system’s safety and reliability. Additionally, the switching operation of a power converter often induces significant voltage fluctuations, necessitating the use of sizable electrolytic capacitors (EC) to mitigate them. However, the substantial capacitance of ECs can lead to a substantial increase in DC-bus fault currents during short-circuit events. To address this concern and bolster the dependability of BESS applications, the implementation of a fast circuit breaker becomes crucial. In light of the paramount importance of a circuit breaker, this paper presents and explores a novel solid-state circuit breaker (SSCB) based on a coupled-inductor. The proposed SSCB can exhibit the capacity to mitigate voltage fluctuations and short-circuit current levels. Subsequently, the proposed SSCB can attain structural simplicity, reduced voltage ripple, and high reliability. Finally, the simulation and experimental investigations can verify the improved current handling, disconnection, and reduced voltage ripple capabilities offered by the proposed SSCB.

Hydrogen-powered electric aircraft have attracted significant interests aiming to achieve decarbonization targets. Onboard DC electric networks are facing great challenges in DC fault protection requirements. Vacuum interrupters are widely used in low voltage and medium voltage power systems due to being environmentally friendly with low maintenance. In this paper a moving coil actuator with compensation coils for a vacuum interrupter, as part of a hybrid direct current circuit breaker, is designed and experimentally tested. Compensation coils are used to improve operating speed compared with original moving coil actuator. Comparisons between four possible connections of compensation coils and original moving coil actuator are carried out. Experimental results show comparisons between different connections of actuator coils in terms of opening time and coil current with a range of pre-charged capacitor voltages. Dynamic performance of each actuator connection is also compared. The actuator with compensation coils is shown to have a higher current rising rate and achieve faster opening speed, which is a critical requirement for electric aircraft network protection. The parallel connection actuator achieves the highest opening speed within 3.5 ms with capacitor voltage of 50 V.

The seismic resilience has become a critical concern for power systems for high-impact, low-probability disasters such as severe earthquakes. In order to enhance seismic resilience for power systems, a novel protective device, the Passive Over-Current Trip (POCT), has been designed in this paper. In the design, the POCT integrates a fuse and a mechanical switch, able to trigger the breaker to interrupt the circuit to ensure effective protection. The POCT has the trip-free feature as it fulfills its protective function without the need for an electric relay requiring a continuous power supply. The proposed POCT provides an immediate and reliable solution for the protection in high and ultra-high voltage applications. To validate the effectiveness of the proposed POCT, shockproof and tripping tests were conducted. A seismic test waveform from the Fukushima earthquake that occurred on March 11, 2011 was used to test POCT. Under such a severe earthquake, no structural or mechanical damage on the associated components in the POCT was found. Also, the POCT is also in compliance with IEEE 693 standard. Finally, various tripping tests show that the POCT can operate within 18 ms when a fault occurs in a power system, which is much shorter than that of a typical high-voltage fuse.

This paper proposes an intelligent wireless monitoring system integrating grey wolf optimization and support vector machine for real-time fault detection in low-voltage circuit breakers. A wireless measurement network collects vibration signals from circuit breakers for feature extraction. An optimized support vector machine model using an improved grey wolf optimization algorithm is developed for fault diagnosis. Experiments demonstrated a 93.2% diagnosis accuracy for the model on single faults. The integrated monitoring system achieved 0.74 AUC, 0.35 F1 score, and 2.8 seconds response time, outperforming other systems. The wireless intelligent monitoring framework enabled efficient fault detection and maintenance for circuit breakers. However, limitations include small dataset size and lack of validation on real breakers. Further research on model optimization and testing on field data will be valuable. In conclusion, this paper proposed and validated an intelligent wireless monitoring system integrating grey wolf optimization and support vector machine for real-time low-voltage circuit breaker fault detection.

The contact of the closing resistance of a certain 1 100 kV circuit breaker is faulty. Two short bolts are falling off and two long bolts are broken and separated. By technical means of macro inspection， dimensional measurement， metallographic analysis and so on， the material， connection and operation conditions are discussed， the finite element analytical model with high precision is developed， and the fault cause is analyzed by considering the height difference of bolt hole between long bolt and short bolt and the impact of operation load. The results show that both long bolts and short bolts are intact， but the long bolts show obvious fatigue fracture morphology. Further analysis shows that when the closing resistance and the active arc contact press cylinder are fully fastened， the height difference of bolt hole between the long bolt and short bolt forms the tension， which loosens the long bolt and produces cracks at the connecting plate， thus the long bolts are broken under the action of long-term opening and closing. The height difference of the blot hole can be identified as the main cause of breaking of closing resistance fastening bolts.

For extremely large ultra-high-voltage (UHV) power transmission and distribution lines with typical project using hybrid reactive power compensation (HRPC), single-phase earth fault (1LG), three-phase ground fault (3LG), phase-to-phase fault (2LS), and two-phase grounding fault (2LG) often occurs. Circuit breaker is one of the most critical equipment of UHV transmission system. And the interruption performance is crucial to circuit breakers’ breaking capability. In this study, formal expressions of the indicators for the interruption performance of the circuit breaker are deduced in case of different faults based on the equivalent-valued parameter circuit based on the structure a UHV demonstration project. The simulations are used to validate the accuracy of formal expressions. Then, the influence of such factors as the location of the fault and the degree of HRPC on the interruption performance of the 1LG, 2LG, 3LG, and 2LS is analyzed. Finally, the interruption performance of circuit breakers under different faults are compared. A quantitative evaluation of the influence of changes in the relevant indicators on the interruption performance of circuit breakers can provide a technical basis for choosing the appropriate design of the circuit breaker in light of the application as well as equipment development and assessment.© 2017 Elsevier Inc. All rights reserved.

For the realization of sustainable society installing renewable energy sources, we have proposed a compact, low‐cost, versatile DC circuit breaker that combines a fuse and a power semiconductor. However, even under the same interruption conditions, there are cases where the interruption success and failure are observed probabilistically; the reason for this is still unknown. In the interruption failure, thermal reignition of an arc discharge occurs inside the fuse under transient recovery voltage. In this study, the spatiotemporal dynamics of the fuse arc was diagnosed for both interruption success and failure by a voltage–current waveform recording, high‐speed arc‐emission videography and borescope‐integrated optical emission spectroscopy, in order to identify the difference between the interruption success and failure. The waveform recording and videography demonstrated that at the arc initiation inside the fuse, the radial arc length for the interruption failure was longer than the interruption success. In the current interruption phase, the radial arc length was still longer, axial arc length was shorter, and arc column resistance was lower for the interruption failure. Further, the optical emission spectroscopy showed that localized regions with higher temperature and electrical conductivity existed for the failure in the current interruption phase. From these results, the dominant factors differentiating interruption success and failure were identified as the arc shape and electrical conductivity of the arc. To improve the interruption performance of the fuse and our DC circuit breaker, it is effective to increase the axial arc length, suppress the radial arc length, and reduce the electrical conductivity of the arc. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A Power Breaker is a mechanical switch that is able to open to allow current to flow under normal conditions and close when there is a disturbance under abnormal conditions, such as a short circuit current disturbance. Damage to the Power Breaker has a considerable influence on the operation of the electric power system, resulting in losses and the operating system of the electric power being disrupted. For this reason, it is necessary to periodically test Power Breaker performance in order to meet operating standards, improve reliability, guarantee quality, and maintain the continuity of electric power distribution. This research was limited to testing before and after the Power Breaker 20 kV Net Cubicles Maintenance located at the Senayan PLTMG Substation during February 2023 in the form of contact resistance testing, Insulation resistance testing, simultaneity testing, and trip relay testing. By testing the performance of the Power Breaker, it is hoped that it can prevent malfunctions that result in damage to the Power Breaker and other components at the Senayan PLTMG Substation. [ABSTRACT FROM AUTHOR]

Failure of islanding detection techniques leads to improper operation of DGs, risk for working personnel, loss of control over voltage and frequency, uncoordinated protection, poor power quality, etc. Therefore, the islanding event (IE) should be identified, and its detection algorithm should be incorporated according to the standard guidelines. Through this paper, a communication-assisted passive islanding detection technique (IDT) is proposed based on an index, which is the ratio of multiplications of superimposed negative sequence voltages and currents of DG and grid sides. Proposed ID is implemented in the modified IEEE-13 bus system through the micro phasor measurement unit. The calculated index is compared with a set threshold to discriminate between the IEs and non-islanding events (NIEs). The calculation of threshold is not very complex as compared to other schemes. The efficacy of the proposed IDT is tested under various system conditions, such as zero power mismatch (ZPM), wide range of active power mismatch, and reactive power mismatch. DG disconnection and unbalanced load test cases are also performed under ZPM condition. Similarly, different NIEs like capacitor switching, load switching, nonlinear load and different fault cases are verified through the proposed IDT. Real-time implementation of proposed IDT is conducted using opal-RT. [ABSTRACT FROM AUTHOR]

AbstractEvaluating the rated MVA sizes of the Circuit Breaker (CB) requires calculating reactance parameters from fault analysis and synchronizing these parameters with the reference re- striking voltage. In this paper two ways are used in controlling X/R ratio of the system to reduce CB size in order to save cost on system configuration. PSS/E program was introduced to facilitate and illustrate the solution. X/R ratio and subtransient reactance were calculated to provide an approach to assess the current and duty interruption of generator buses with contributions from all other buses. The effect of reduction factors and NACD for the symmetrical component of the short circuit current is also applied in our proposed method. The obtained results proved that applying the reduction factor technique in New England system reduces the rated interruptions of C.Bs, and CB rate is also minimized in Bismayah132kV power plant from Iraqi grid utilizing effective switching which economizes choosing CB. It is concluded that the two techniques can be used successfully for designing CB ratings with a minimum cost.