This research proposes a solid-state dc circuit breaker for low voltage dc system based on reverse-blocking integrated gate-commutated thyristor (IGCT). The circuit break...Show More
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Abstract:
This research proposes a solid-state dc circuit breaker for low voltage dc system based on reverse-blocking integrated gate-commutated thyristor (IGCT). The circuit breaker topology gets easier as a result of reverse-blocking IGCTs’ ability to withstand reverse voltage. To further enhance the breaking process, we develop a snubber branch with metal oxide varistors (MOVs) and capacitance. The advantages and disadvantages of three distinct snubber branches—the no-snubber, the resistance–capacitance (RC), and the MOV-C snubber branch—are then contrasted. In addition to suppressing high-frequency oscillation caught by the parasitic MOV parameters, the structure with MOV-C snubber branch also blocks low-frequency harmonics brought on by RC snubber branch. Moreover, this structure can slow down the rate at which the voltage rises during the breaking process. Comparatively speaking to the RC snubber branch and no-snubber branch structures, it is more appropriate for solid-state dc circuit breakers. Finally, a solid-state dc circuit breaker prototype based on RB-IGCT and MOV-C branch has been created. The maximum overvoltage is 1.5 kV and the rated voltage is 750 V. The maximum breaking current is 10 kA and the rated current can be 2 kA.
Flexible power allocation, high system efficiency, high power supply capacity, minimal line loss, and high power quality are the advantages of the dc system [1], [2], [3], [4], [5], [6]. The short fault's effect on the current, however, manifests much more quickly in the dc system due to its low impedance [7], [8], [9]. Additionally, since dc fault current does not naturally have a zero-crossing point, cutting off the fault current is more difficult [10], [11]. Higher standards for the protection of the dc system have been proposed as a result of these challenges. With its great current-breaking capabilities and quick operating speed, the dc circuit breaker has provided the best performance for the short fault of a dc system. Solid-state dc circuit breakers (SSCBs), based on power electronic devices, have the advantages of a simplified structure, faster breaking speed, and no arc breaking as compared to mechanical dc circuit breakers (MCBs) and hybrid dc circuit breakers (HCBs). Moreover, SSCBs have a longer electrical life and greater dependability than the other two topologies due to the no arcing and moving structures [12], [13], [14]. The three topologies of dc circuit breakers are compared in Table I
[1]. The SSCB has a comparatively low capital expenditure, but its operating cost is quite high due to the long-term loss. Although SSCBs have higher on-state losses than MCBs and HCBs, their efficiency can exceed 99.5%, and current heat dissipation technology can guarantee the safety of the devices. Thus, SSCBs are frequently used in the data center, dc distribution network, and rail transit industries [15], [16], [17]. The rated current of the system is often between 1 and 2 kA in these low-voltage, high-capacity dc application circumstances. The fault current frequently reaches 10 kA within 1 ms, which need SSCB to isolate the short faults.
Characteristics Comparison of DCCB
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