Comparative Analysis of Power Loss Associated with Topology of Bi-Directional Z-Source Circuit Breakers

Bhatta, Sagar; Zhang, Yucheng; Fu, Ruiyun

doi:10.1109/secon.2018.8479167

Cited by 15 publications

(2 citation statements)

References 8 publications

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“…Since most of the time, a ZCB stays in an "ON" status, its steady-state power loss is critical for system efficiency. The power-loss conditions of three bidirectional ZCB topologies were compared in [25]. The study formulized the efficiency of power delivery in ZCBs at rated load conditions as a cost function and revealed that the Inter-Cross-Connected Bi-directional Z-source Circuit Breaker (ICC-BZCB) topology, as shown in Figure 1, had low overall power loss compared to the other two topologies.…”

Section: The State Of the Art Of Z-source Circuit Breakersmentioning

confidence: 99%

Assessment of Cable Length Limit for Effective Protection by Z-Source Circuit Breakers in DC Power Networks

Bhatta

Keller

et al. 2021

Electronics

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This paper introduces groundbreaking research on how to assess the Cable Length Limit (CLL) to ensure effective protection by Z-source Circuit Breakers (ZCBs) in DC power networks. It has been revealed that the line parameters of power cables have a significant impact on the cutoff performance of ZCBs. The question of assessing the CLL has been raised as an unsolved problem. In this paper, a method of CLL assessment is proposed based on physical models and simulation tests. To verify the proposed method, two studies were performed to assess the Cable Length Limits depending on fault levels and power delivery levels, respectively. The ZCB parameters were specified for a simulation testing system for a 5 MW distribution line feeder. The effectiveness of ZCB protection was tested in groups of simulation tests with various impacting quantities, i.e., cable lengths, fault current levels, and power delivery levels. The effective cable lengths for the ZCB to detect and successfully interrupt a faulty branch in the DC network were assessed and analyzed. The testing results prove that the CLL decreases along with a decreasing fault current level, as well as an increasing power delivery level. Based on data analysis, an equation was derived to calculate the effective length of the ZCB for DC lines, and the equation can be used to generate new CLL curves for various load-power requirements. This study could increase the reliability of a ZCB’s response to a fault in DC transmission and distribution lines. It could also help power system designers/operators to maintain reliable protection with ZCBs in DC power system networks.

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Section: The State Of the Art Of Z-source Circuit Breakersmentioning

confidence: 99%

Assessment of Cable Length Limit for Effective Protection by Z-Source Circuit Breakers in DC Power Networks

Bhatta

Keller

et al. 2021

Electronics

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“…The reference [33] performed the analytical evaluation of system impedance during fault in a DC system including a group of power electronic devices. The operational power losses were compared among the several existing ZCB topologies in [34]. Based on our prior studies on ZCB topologies, the research of this paper is performed on the topology of the intercross connected bidirectional Z-source circuit breaker (ICC-BZCB) introduced in [35], because of its high efficiency.…”

Section: Zcb and Hif Detection/interruption Modesmentioning

confidence: 99%

A New Method of Detecting and Interrupting High Impedance Faults by Specifying the Z-Source Breaker in DC Power Networks

Bhatta

Zhang

2020

Electronics

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High impedance faults (HIFs) that cause a relatively smaller current magnitude compared to the traditional low impedance faults are not easily detectable but can cause an extreme threat to electric apparatus and system operation. This paper introduces a new method of detecting and interrupting HIFs in DC power networks by specifying Z-source circuit breakers (ZCBs). The ZCB is a protective device for high power DC branches, with the capabilities of protecting bidirectional power flow and automatic/controllable turnoff function. In this new method, the operational mode of ZCB (i.e., either the detection mode or interruption mode) can be specified. Beyond previous research, the theoretical analysis has been performed on this method and the mathematical relationship between the maximum HIF resistance and required Z-source capacitance has been derived and verified. It has been found that the ZCB can respond to a HIF accordingly when its capacitances are properly adjusted in the ZCB circuit. With the adjustment of these Z-source capacitances, the ZCB can be specified to detect and report a HIF status to power system operators, or cut off the HIF branch and protect the rest of the DC system directly. The new method can detect/interrupt a HIF that is as small as 2 times of its nominal rated current and the effectiveness and general usage of the derived equation have been verified by both low power experiments in lab and high power simulation tests.

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A New Method of Coordinating ZCBs and Fuses for a Reliable Short-Circuit Protection in DC Power Networks

Fu,

Montross

2022

IEEE Access

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Comparative Analysis of Power Loss Associated with Topology of Bi-Directional Z-Source Circuit Breakers

Cited by 15 publications

References 8 publications

Assessment of Cable Length Limit for Effective Protection by Z-Source Circuit Breakers in DC Power Networks

Assessment of Cable Length Limit for Effective Protection by Z-Source Circuit Breakers in DC Power Networks

A New Method of Detecting and Interrupting High Impedance Faults by Specifying the Z-Source Breaker in DC Power Networks

A New Method of Coordinating ZCBs and Fuses for a Reliable Short-Circuit Protection in DC Power Networks

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