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Bi-directional solid-state circuit breakers (BDSSCBs) can provide performance benefits over mechanical fault protection devices. A common-source configuration of normally ON, junction field effect transistors (JFETs) is favorable for BDSSCB implementations. SiC 0.1-cm² 1200-V JFETs designed for normally-ON operation at a zero-volt gate bias, and having low leakage currents, were used in the fabrication of a 30-A BDSSCB switch module. Operation of the module under continuous current and during turn-OFF transitions was evaluated to verify the parallel scalability of the common-source configuration. A bi-directional snubber connected across the switch module mitigated inductive voltage overshoot during BDSSCB turn-OFF transitions. At turn-OFF, under maximum power tests in both directions, the load current was reduced from 30 A to 0 A in approximately 10 μs, with a supply voltage of 600 V, and a BDSSCB peak voltage of 680 V. These results demonstrate the functionality and current scalability of this BDSSCB topology.

Conventional circuit breakers suffer from two main deficiencies: they are slow to operate and develop an electrical arc. These may be overcome by using solid-state switches which in turn introduce other problems, most significantly power dissipated while in the on-state. Nevertheless, a number of solid-state devices are candidates for implementation as low-voltage circuit breakers and there are several options based on the semiconductor material that may function as high-power switches. This paper presents a unique, extensive and systematic evaluation of these options. Voltage-controlled devices are selected due to the simplicity of the controlling circuit and their resilience to $dv$/$dt$-induced switching. Properties of fully solid-state circuit breakers are established and systematic comparisons are made among switches built of silicon and other wide bandgap (WBG) devices such as SiC MOS and GaN HEMT transistors. Using SPICE simulation it is shown that solid-state circuit breakers (SSCBs) based on WBG devices exhibit superior characteristics compared with silicon devices, with faster switching and higher voltage and current ratings. Hybrid circuit breakers, combining both conventional and solid-state switches, are discussed too and a new design circuit is simulated and compared to both conventional and fully solid-state designs.

The following sections are included:

• Introduction
• Social Stigmatization
• Removing the Social Stigma in Mental/Health Issues
• The Tech World and Their Destigmatizing Solutions
• Conclusion
• References
• Appendix

In order to improve the mechanical structure of the type of fault resolution precision high voltage circuit breaker spring mechanism, the paper analyzes the characteristics of the circuit breaker and the combination of mechanical vibration signal, PSO algorithm (PSO), SVM parameter optimization method, proposed collaborative dynamic acceleration constant inertia weight particle swarm optimization (WCPSO) optimization, support vector machine (SVM) analysis breaker fault classification parameters and kernel function parameters. The vibration signal circuit breaker empirical mode decomposition, the total intrinsic mode components through energy analysis to obtain the required fault feature vectors and support vector machine as input, the use of dynamic acceleration constant synergy inertia weight PSO support vector machines penalty factor C and radial basis kernel function parameters optimize the fault feature vector signal input test samples after SVM training sample trained optimized for fault status classification. The experimental analysis of this method can effectively improve the resolution of the breaker failure signal type accuracy.

This paper proposes the design of a state monitoring system for energy-storing closing spring, to ensure the reliable and safe operation of the spring operating mechanism in circuit breakers. Firstly, the LW25-126 SF6 circuit breaker is used as the experimental sample. Secondly, the photoelectric encoder is utilized to monitor the stroke curve of closing contact. Thirdly, the acceleration sensor monitors the working stroke of closing spring. Fourthly, the pressure sensor is used to monitor the closing pressure. Lastly, the current transformer monitors the current of the energy-storing motor. In addition, the output data of these sensors is collected by the MPS-140801 acquisition card to be read and processed by LabVIEW before the processed data is displayed and stored in the upper computer. The analysis results demonstrate that the state of energy-storing close spring can be accurately monitored by using the proposed state-monitoring system.