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This paper proposes a novel ultra-Fast self-powered bidirectional solid-state circuit breaker (SSCB) with voltage overshoot suppression that uses gallium nitride (GaN) switches with very low conduction losses. This SSCB can be used in low and medium AC/DC networks for both short-circuit protection and overcurrent protection. An exhaustive methodology for RCD snubber design applied to SSCBs is provided. A comprehensive review of the technical literature is presented exhibiting that the proposed SSCB reduces conduction losses and detection time in comparison with other similar SSCBs. The performance features of the proposed SSCB are verified through the functional tests that are carried out employing a hardware-implemented prototype. Experimental results confirm that our proposal is able to detect and process the short-circuit failure in 282ns; the authors have not found any faster results in the literature.

Next generation fleets will rely on medium-voltage direct-current (MVDC) electric power distribution systems utilizing high power density and high-efficiency components. One key gap to make such MVDC systems feasible is a super-fast, high-efficiency, and high power density protection device. The U.S. Navy has previously developed a 1 kV, 1 kA solid state circuit breaker (SSCB). A new 2 kV, 1.2 kA SSCB has been designed by NPS with collaborating partners that has quadrupled power density. This innovative insulated gate bipolar transistor (IGBT)-based SSCB consists of anti-series IGBT modules, a parallel resistor-capacitor (RC) branch, and an electronically triggered metal-oxide varistor (MOV) branch. The novel electronically controlled MOV is comprised of a MOV in series with a silicon controlled rectifier (SCR) passively triggered during the IGBT turn-off process, improving the trade-off between the leakage current and clamping voltage. The use of a lower IGBT gate voltage allows the elimination of current limiting inductors, increasing the SSCB power density. This thesis focuses on the switching and thermal tests necessary to validate the implemented concepts, and the data will be used for down-selecting technical directions, improving the SSCB performance. The results show that the SSCB is sufficient to interrupt most faults while containing peak current and voltage within design parameters and the efficiency target can be met with comfortable thermal margins. Lieutenant, United States Navy Approved for public release. Distribution is unlimited.

This paper investigates a degradation of SiC power device for DC circuit breaker through repetitive unclamped inductive switching (UIS) tests. Being much lower compared with Si devices, it has been considered an application for DC circuit breakers using SiC semiconductor. In order to use for the DCbreaker, it is essential to evaluate the destructive endurance for UIS test.This paper evaluates a deterioration phenomenon by paying attention to the decrease of the gate voltage of the SiC-MOSFETs under the degradation at repetitive UIS test.

Naval Postgraduate School and the Naval Surface Warfare Center Philadelphia Division, University of Connecticut, and Clemson University propose to advance the response speed, power density, efficiency, and altitude capability of circuit breaker technology by developing a fast lightweight altitude-ready solid state circuit breaker for hybrid electric propulsion (FLASH). This thesis describes the procedure and methods used to create a nondestructive testbed that identifies the potential issues in the circuit breaker related to electromagnetic interference (EMI) susceptibility. The testbed uses magnetic and electric field injection to simulate harsh EMI environments and pinpoints the exact areas within a system that are susceptible to EMI. Furthermore, this thesis recommends low-cost solutions to correct the identified problematic areas and components. Lastly, the testbed designed in this thesis can be used on the FLASH circuit breaker as well as a wide range of other applications and electrical circuits. This thesis will identify the potential issues in the circuit breaker related to EMI and proposes solutions that will help the team integrate the solutions in the circuit breaker design. In addition, it develops a tool used to enhance the EMI performance of the circuit breaker components. Lastly, this thesis documents the results of the full power test and validates the proposed solutions with experimental data. NASA Glen Research Center 21000 Brookpark Rd, Cleveland, OH 44135 Lieutenant, United States Navy Approved for public release. Distribution is unlimited.

DC fault current limitation is important for the low-voltage dc distribution network, because the existing dc selective protection cannot act fast enough. However, the typical dc fault current limiting method—installing dc reactors directly in the dc system—will lead to negative influence on the system normal operation and dc circuit breaker (DCCB) fast isolation. This paper proposed a novel solid-state circuit breaker (SSCB) with self-adapt fault current limiting capability, namely, no negative influence on the dc distribution network normal operation, swift fault current limiting response to the dc fault, and efficient cooperation between the fault current limitation and isolation. The hybrid configuration strategy of the proposed SSCB and mechanical DCCB for multiterminal dc distribution network is proposed to reduce the conducting power loss and investment from the scale of the whole system. Finally, the experiment tests and simulation cases are carried out to verify the working principle and superiorities of the proposed SSCB.

A cost-efficient Solid-State Circuit Breaker (SSCB) by using the proposed matrix configuration of the main branch for Low Voltage Direct Current (LVDC) microgrid applications is presented. The proposed SSCB can achieve 99.9% efficiency from 50% to 100% load which is comparable to traditional mechanical circuit breaker. The matrix configuration is an optimized design considering cost, efficiency, and current interruption capability. It is suitable for cost and space sensitive applications such as residential and commercial DC buildings. Due to the superior efficiency, the proposed SSCB is natural cooled design which ensures low acoustic noise and suitable for residential applications. Performance of the proposed SSCB has been evaluated analytically. Experimental verification is performed on a 400V/40A prototype.

With the continuous development of More Electric Aircraft, the protection of its DC power supply system is more important. DC solid-state circuit breaker (SSCB) has better performance in short-circuit fault protection of DC power supply system. Therefore, this paper mainly introduces the More Electric Aircraft DC power supply system protection based on a novel SSCB. The SSCB uses two transformers and two thyristors to realize the bidirectional protection of the system, and has a simple structure and low loss. This paper introduces the DC power supply system short-circuit fault principle at first, and then, introduces the working principle of the novel SSCB, and the SSCB is verified by simulation experiment at last.

An effective DC solid state circuit breaker (SSCB) based on cathode-short MOS-controlled thyristor (CS-MCT) is evaluated in this paper. Firstly, the low on-state resistance and high surge current capability of the CS-MCT are proved through experimental results, thus indicating that the CS-MCT is a competitive device in SSCB applications. Moreover, an effective SSCB based on CS-MCT is designed. Both the behaviors of the CS-MCT and the SSCB topology is studied via simulations and prototype experiments. According to the research, the proposed SSCB can achieve a reliable fault interruption capability once the mis-triggering of the CS-MCT is effectively suppressed.

Solid‐state circuit breakers (SSCB) show great promise to become the key element in the protection of low‐voltage direct current microgrids. SSCBs operate in the microsecond range and employ semi‐conductor devices that have strict safe operation area limits. Therefore, the design of the SSCB needs to consider the effects of fault detection delays and semi‐conductor safe operation area limitations. This paper derives SSCB design criteria that consider the effect of different detection methods with different detection delays under varying system constraints. The design space is investigated in a sensitivity analysis, which provides insights into the operation boundaries of SSCB and explains how a combination of fault detection methods can reduce the SSCB size. The insights from the theoretical and sensitivity analysis are used to propose an SSCB design flowchart. SSCB prototype is developed and tested in different scenarios under nominal grid voltage and current. The derived design constraints can be used for efficient SSCB design and also to evaluate the effects of different protection schemes on the required SSCB size.

In this work, a current derivative assisted protection coordination system between the fast protection devices in a power electronic converter dominated radial DC microgrid is proposed. A circuit based model of a grid connected radial DC microgrid with energy storage unit is developed in PLECS that includes solid-state circuit breaker model as protection device. Microgrid fault dynamics have been analyzed theoretically to modify the standard time graded breaker coordination curve for faster fault isolation. We demonstrate that faster response is achieved by adding a corrective term for breaker coordination based on the derivative of the sensed current and coordinated operation between upstream and downstream protection devices without any active communication. The performance of the proposed approach is compared in simulation with regular time graded breaker operation for validation. In addition, experimental results are provided to demonstrate the effectiveness of the proposed method for faster fault isolation in a 380V DC system.

In this study, the basic device features of a novel monolithically integrated solid-state-circuit-breaker (MI-SSCB) are demonstrated and analyzed using numerical simulations. Thereby, the MI-SSCB is built according to the concept of the dual thyristor. But, in comparison to similar technical solutions reported in literature, due to the advanced device structure proposed in this study a monolithically integration could be achieved for the first time.

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.

Fast increasing dc fault currents in dc shipboard distribution systems require fast dc protective devices and protection methods. Solid-state circuit breakers (SSCBs) inherently have fast protection speed and thus are proper for dc shipboard distribution protection. Based on the analysis of the fault current features in dc shipboard distribution systems, the design of the system protection employing SSCBs is discussed from the perspectives of SSCB technologies, design requirements, and protection methods. Fast speed, low cost, low loss, and optimized design are major challenges of SSCB-based dc shipboard distribution protection.

Due to the interconnected scheme of multiple components, such as distributed generators, storage systems, and loads through converters to a common bus in DC microgrids, the possibility of fault occurrence is increasing significantly. Meanwhile, due to the huge and rapid increase of short-circuit currents, the development of a small- and large-scale DC system requires a reliable and fast protection system to ensure fault clearance and maintain safety for the rest of the system. Thus, fault protection has been focused on as one of the most critical issues in a direct current network. The application of traditional circuit-breakers for DC fault protection has the drawback of slow operation, which requires a high rating power equipment. Recently, the high speed and excellent performance capabilities of semiconductor breakers have attracted a lot of attention and been considered as an optimal solution for fast DC fault interruption. In this study, a bidirectional Insulated-Gate Bipolar Transistor (IGBT) semiconductor breaker, suitable for the fault protection of low-voltage DC networks, is proposed. The operating characteristics of this breaker are based on changes in the circuit current and terminal voltage of IGBTs. It detects the abrupt change of the terminal voltage as an abnormal condition and isolates the faulted branch in a short time to prevent the operation disturbance in the healthy part of the network. Therefore, for the entire protection of a typical 400V DC-microgrid cluster, breakers need to be integrated and examined in each branch and the interconnected lines. The proposed protection method in this study is examined in a Simulink®/MATLAB environment to analyze and assess its operation.

The development of the DC microgrid system has promoted the development of the DC circuit breaker. However, the traditional DC circuit breaker exists many problems such as long period of fault interruption, complex circuit structure, existing arc, low reliability and low anti-interference. Aiming to solve these problems, an improved solid-state DC circuit breaker was proposed in this paper. This improved solid-state circuit breaker uses a transformer instead of LC legs which exist in the traditional Z-source circuit breakers to realize the function of turning off the thyristor. The working principle and designing process are discussed in this paper according to the results of simulation based on Saber. And the operation performance of the improved solid-state circuit breaker is validated by the calculation and simulation results.

In this work, the application of cathode-short MOS-controlled thyristor (CS-MCT) in DC solid state circuit breakers (SSCB) is evaluated. Firstly, static and dynamic characteristics of CS-MCT are presented, and a low on-state resistance combined with a high surge current capability makes CS-MCT a promising candidate for SSCB. Furthermore, fault interruption process of SSCB based on CS-MCT is demonstrated via TCAD simulation as well as experiment. According to the research, SSCB based on CS-MCT can achieve a high fault current interruption capability once the mis-triggering of internal thyristor is effectively suppressed. And a contradictory relationship between energy loss and interruption capability of the SSCB is also found, which implies a trade-off design should be taken into consideration.

These days, the widespread use of sensitive loads and distributed generators makes the solid-state circuit breaker (SSCB) an essential component in power circuits to achieve a high power quality for AC Grids. In traditional AC SSCB using SCRs, some auxiliary mechanical devices are required to make the reclosing operation possible before fault recovery. However, the proposed AC SSCB can break quickly and then be reclosed without auxiliary mechanical devices even during the short-circuit fault. Moreover, its fault current breaking time is short and its SSCB reclosing operation is fast. This results in a reduction of the economic losses due to fault currents and power outages. Through simulations and experiments on short-circuit faults, the performance characteristics of the proposed AC SSCB are verified. A design guideline is also suggested to apply the proposed AC SSCB to various AC grids.

The SiC ETO concept, developed based on the SiC gate turn-off (GTO) thyristors, has the advantages of simple voltage controlled gate drive, very high blocking voltage, low forward voltage drop and large turn-off current capability, demonstrating a high suitableness for medium voltage solid state circuit breaker applications. In this paper, a 15 kV/200 A solid state circuit breaker (SSCB), which is suitable for medium voltage direct current (MVDC) power systems protection, is designed and developed based on the parallel and high temperature operation of the 15 kV SiC emitter turn-off (ETO) thyristors. To realize the 200A current rating, three SiC ETOs are connected in parallel. The static and dynamic current sharing of the SSCB is tested at 4.5kV/200A, showing it is an ideal candidate for the medium voltage SSCB applications.

This paper reports a SiC-based solid-state circuit breaker (SSCB) with an adjustable current-time (I-t) tripping profile for both ultrafast short circuit protection and overload protection. The tripping time ranges from 0.5 microsecond to 10 seconds for a fault current ranging from 0.8X to 10X of the nominal current. The I-t tripping profile, adjustable by choosing different resistance values in the analog control circuit, can help avoid nuisance tripping of the SSCB due to inrush transient current. The maximum thermal capability of the 1200V SiC JFET static switch in the SSCB is investigated to set a practical thermal limit for the I-t tripping profile. Furthermore, a low fault current ‘blind zone’ limitation of the prior SSCB design is discussed and a new circuit solution is proposed to operate the SSCB even under a low fault current condition. Both simulation and experimental results are reported.

This review present the state of the art of the circuit breaker for photovoltaic applications. The work consider the most used systems for this kind of applications, and in particular, starting from the state of the art of the mechanical Circuit Breaker, introduce the new emerging technologies based on Solid State Circuit Breaker and Hybrid Circuit Breaker. All the proposed systems will be compared each other in terms of robustness, galvanic insulation, intervention time, remote control etc. The study highlight that the Solid State Circuit Breaker are better in terms of protection capability and customization, thanks to the software based sensing method. This allow to design better protections for lines and equipment. For this reason, the authors think that in the future all circuit breaker technology will substitute the sensing hardware with digital based sensing. The last part of the paper introduce a laboratory prototype solid state circuit breaker, build to test different protection methods and understand limits of the digital sensing method. The experimental results confirm the higher performance in terms of accuracy, fast response and customization of the digital sensing if compared with classical hardware sensing.

Recently according to the development of DC transmission which is high efficiency, stability of DC grid has become a major concern. Therefore, the reliable DC SSCB (Solid-State Circuit Breaker) is required in order to secure high safety. The previous DC SSCB is unstable and many elements are required in order to perform the operating duty. This paper proposes a new DC SSCB. Since the proposed DC SSCB does not cause delay of breaking operation caused by charging operation, it can break an accident quickly. Also, since it can perform the operation duty with a few elements, it is economical. The operating characteristic of the proposed DC SSCB is verified by simulations on short circuit fault. Also, this paper suggests the design guidelines so that it can be applied to any other DC grid.

This paper discusses SSCB (Solid State Circuit Breaker) based DC shipboard distribution system protection in different perspectives. Unique features of DC distribution faults are analyzed and corresponding protection requirements are discussed. Latest SSCB technologies are presented and suitability for DC shipboard power systems is addressed. An overall evaluation gives out advantages and disadvantages of applicable SSCB based DC distribution protection methods.