Breaker Devices Research Articles

Copper-Nickel/SiC composites for applications on contact electrodes

Novel copper-nickel matrix composites reinforced with silicon carbide (SiC) micro particles for metal contact applications were manufactured by powder metallurgy technology and were experimentally characterized. Cu and Cu alloys are commonly used as metal contact for either vacuum, oil, or SF6 in low-voltage circuit breaker devices, but their application in environments with the presence of oxygen is limited due to their tendency to form high-resistance copper oxides. Thus, the addition of Ni as an alloying element provides resistance to both humidity and several corrosive environments and increases the composites' hardness, mechanical strength, and wear resistance. Moreover, SiC was chosen due to its contribution to mechanical strength, mouldability, low production cost, and non-reactive nature at ordinary temperatures. Here, three SiC particle size distributions were considered, and it was found that the composites' physical properties are also dependent on the ceramic loading. After evaluating these properties, two specific SiC concentrations were potentially considered for electrode applications: 10 wt% and 20 wt%. The obtained hardness values are in the range of 55 – 65 HR30T which guarantees the necessary strength without detriment of the contact area whereas the welding is minimized. In addition to a homogeneous particle distribution in the solid material, specific wear resistance of ∼10-5 mm3N-1m-1 and electrical conductivities of ∼20 %IACS were obtained. Considering these parameters, Cu-Ni/SiC composites' performance is not compromised compared to commercial Ag/WC materials commonly used in metal contact applications.

Analytical Modelling of the Quasi-Static Operation of a Monolithically Integrated 4H-SiC Circuit Breaker Device

In this work, an analytical model describing the quasi-static operation of a monolithically integrated SiC solid-state circuit breaker (SSCB) device is rederived and refined. This SSCB is based on a 4H-SiC JFET technology offering a self-sensed blocking mechanism. The proposed model is solely based on physical parameters including the SSCB design parameters. With respect to the refinement, the proposed model is not limited to one-sided pn-junctions, considers incomplete ionization of dopants, and is able to represent breakdown characteristics. In this regard, the JFET gate breakdown characteristics are derived taking thermionic emission, space-charge-limited current and impact ionization into account. To calculate the SSCB output characteristics, a bisection-based optimization algorithm is applied carefully considering individual JFET operating states.

Adjustable Current Limiting Function With a Monolithically Integrated SiC Circuit Breaker Device

This paper proposes a current limiting function for a self-sensing and self-triggering monolithically integrated SiC circuit breaker device. The proposed function provides the device not only with a fast-response current breaking operation but also with the current limiting operation, including supplying a constant current to the load and preventing the detection of inrush currents. This function is suitable for replacing mechanical conductors in initial charging circuits within rectifiers and safety equipment in case of overcurrent phenomena. The proposed method achieves certain constant currents through a simple variation of the gate-drive circuit with the adjustable parameters of an additional MOSFET. The mechanism of the current limiting function is verified using TCAD simulations based on certain conditions. Consequently, experimental results verified that the circuit breaker device with the current limiting function reduces the inrush current by up to 76.9% using a 500 VDC distribution circuit system.

A Monolithically Integrated SiC Circuit Breaker

In this letter, a monolithically integrated SiC circuit breaker device providing self-triggered blocking operation is presented. The proposed topology is implemented into a common 4H-SiC JFET technology, which offers conventional cell design and chip scaling opportunities. Basic operation and design implications are discussed on the basis of quasi-static electrical measurements of fabricated nJFET, pJFET and circuit breaker devices. The design of experiment including a variation of channel length and channel doping dose reveals a distinct effect on the design targets, especially on on-state resistance, trigger current and blocking voltage. The investigated devices exhibit trigger current density levels of up to 2.8 A/cm2 and self-sustained blocking capability up to 795 V DC-link voltage. On-state resistance at room temperature is determined to 0.93 $\Omega $ cm2 but drastically decreases at elevated temperatures, as is shown in the experiments.

RELAP5 Modeling of a Siphon Break Effect on the Brazilian Multipurpose Reactor

This work presents the thermal-hydraulic simulation of the Brazilian Multipurpose Reactor (RMB) using the RELAP5/Mod3 code. The RMB will provide Brazil with a fundamental infrastructure for the national development on activities of the nuclear sector in the areas of social, strategic, industrial applications and scientific and technological development. A RELAP5/Mod3 code model was developed for thermal-hydraulic simulation of the RMB to analyze the phenomenology of the Siphon Breakers device (four flap valves in the cold leg and one open tube for the atmosphere in the hot leg) during a Loss of Coolant Accident (LOCA) at different points in the primary circuit. The Siphon Breaker device is an important passive safety system for research reactors in order to guarantee the water level in the core under accidental conditions. Different simulations were carried out at different location in the Core Cooling System (CCS) of the RMB, for example: LOCA before the CCS pumps with and without pump trip and LOCA after the CCS pumps and the heat exchanger. In all RELAP5/Mod3 code simulations, the Siphon Breaker device's performance after a LOCA was effective to allow enough air to enter the outlet pipe of the CCS in order to break the siphon effect and preventing the pool level from reaching the riser (chimney) and the RMB core discovering. In all cases, the reactor pool level stabilized at about 5.5 m after the end of the LOCA simulation and the fuel elements were kept underwater and cooled.

A quasi-optimal energy resources management technique for low voltage microgrids

The increasing penetration of Distributed Energy Resources (DERs) in modern power systems is introducing new challenges for system stability and control. The stochasticity of Renewable Energy Sources (RESs) and the unpredictable behaviour of demand, make it necessary to develop intelligent Energy Resources Management (ERM) methodology, able to actively regulate the actors of the electrical network. This paper proposes a new quasi-optimal control algorithm, designed for LV breaker devices, aiming to manage DERs in a distributed and scalable approach. The developed ERM technique is able: (1) to control the energy consumption at the Point of Common Coupling (PCC) (with the possibility to join Active Demand Response (ADR) programs or to provide flexibility/energy reserve), when the microgrid itself is connected to the main grid; (2) to control the frequency profile when the microgrid is operating in islanded mode, using information provided by real time measures.

Sistem Proteksi Arus Bocor Menggunakan Earth Leakage Circuit Breaker Berbasis Arduino

Touching a live part of electrical equipment either intentionally or unintentionally can cause an electric shock. The touch can occur directly or indirectly and results in the flow of electric current through the human body to the ground. This electric current is known as the leakage current and can have fatal effects on the human body such as burns, cramps, faint and death. This paper aims to design a prototype protection model of the earth leakage circuit breaker device based on Arduino (ELCBA) to protect the human body from the electrical hazards. The performance of the ELCBA is investigated by detecting the earth leakage current to the grounding system (TN). The prototype is designed and simulated by using Proteus software. Based on the response test carried out on the prototype, it can be concluded that the ELCBA can operate properly to disconnect the electric circuit if the leakage current is detected greater than or equal to 30 mA with a time delay of 15 ms and to reclose the circuit again after 5 minutes.

Design on the HCB Based on IGCT and Neural Network Current Detection

Nowaday,the traditional circuit breaker is which action slow, poor reliability, can not meet Large grid interconnection and flexible AC transmission requirements. To address those shortcomings of traditional circuit breaker,an idear is put forward that traditional mechanical circuit breaker combinates of power electronic switch-IGCT to build a new type of hybrid circuit breaker device (Hybrid Circuit Breaker shorted at HCB). Basing on natural converter circuit principles,when grid line failure,the novel device adopts Elman neural network to detect short-circuit fault current,can disconnect quickly by IGCT’s rapidity to ensure the safety of the power grid and improve switching speed and service life of the mechanical switch. It has a very important significance in fast switching of power system. DOI: http://dx.doi.org/10.11591/telkomnika.v11i8.3130

Magnetic Method to Characterize the Current Densities in Breaker Arc

The purpose of this research was to use magnetic induction measurements from a low voltage breaker arc, to reconstruct the arc’s current density. The measurements were made using Hall effect sensors, which were placed close to, but outside the breaking device. The arc was modelled as a rectangular current sheet, composed of a mix of threadlike current segments and with a current density varying across the propagation direction. We found the magnetic induction of the arc is a convolution product of the current density, and a function depending on the breaker geometry and arc model. Using deconvolution methods, the current density in the electric arc was determined.The method is used to study the arc behavior into the breaker device. Notably, position, arc size, and electric conductivity could all be determined, and then used to characterize the arc mode, diffuse or concentrated, and study the condition of its mode changing.

Ribbon Breaker Device for Type SR Winder

Ribbon Breaker Device for Type SR Winder