DC Protection on the Electric Ship

Hamilton, H.; Schulz, Noel N.

doi:10.1109/ests.2007.372101

Cited by 19 publications

(4 citation statements)

References 11 publications

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“…Current LV standardization defines LVDC system to fulfill following requirements. • Maximum earth voltage 240 VDC • Maximum contact voltages 50 VAC and 120VDC • Insulation monitoring needs to be used to at least give a alarm of insulation decrease in ungrounded system • Earth fault needs to be cleared within 2 hour in ungrounded system • DC network short circuit needs to be cleared within 5s • Customer AC network short circuit needs to be cleared within 0.4s in grounded system and within 0.8s in ungrounded system [10,11] Protection devices commercially available for LV dc systems are fuses, molded-case circuit breakers (MCCB), LV power CBs, and isolated-case CBs. Some of these models are specially designed for DC, but most can be used in ac and dc applications.…”

Section: Lvdc Protection Systemmentioning

confidence: 99%

Protection Scheme for DC Microgrid Distribution System

Deng

Wang

Duan

2012

AMR

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The low voltage DC (LVDC) distribution system is a new concept and a promising technology to be used in the future smart distribution system having high level cost-efficiency and reliability. In this paper, a low-voltage (LV) DC microgrid protection system design is proposed. Usually, an LVDC microgrid must be connected to an ac grid through converters with bidirectional power flow and, therefore, a different protection scheme is needed. This paper describes practical protection solutions for the LVDC network and an LVDC system laboratory prototype is being experimentally tested by MATLAB/SIMULINK. The results show that it is possible to use available devices to protect such a system. But other problems may arise which needs further study.

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Section: Lvdc Protection Systemmentioning

confidence: 99%

Protection Scheme for DC Microgrid Distribution System

Deng

Wang

Duan

2012

AMR

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“…T HE prevalence of dc distribution is a consequence of an increasing reliance on distributed renewable energy sources, higher penetrations of electric vehicles and storage systems, and an overall rise in dc loads such as computers, solid-state lighting, and building networks [1]. This prevailing trend is not limited to land-based systems, as attempts to further optimize aircraft [2] and shipboard systems [3] using the more-electric and allelectric concepts has also given rise to an increased dependence on dc distribution within such ad hoc configurations. In general, employing dc distribution over ac has the potential to reduce losses in feeders, provide improved power quality, enhance reliability, and reduce the number of power conversion stages [4].…”

Section: Introductionmentioning

confidence: 99%

Diagnosis of Series DC Arc Faults—A Machine Learning Approach

Telford

Galloway

Stephen

et al. 2017

IEEE Trans. Ind. Inf.

109

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Increasing prevalence of dc sources and loads has resulted in dc distribution being reconsidered at a microgrid level. However, in comparison to ac systems, the lack of a natural zero crossing has traditionally meant that protecting dc systems is inherently more difficult-this protection issue is compounded when attempting to diagnose and isolate fault conditions. One such condition is the series arc fault, which poses significant protection issues as their presence negates the logic of overcurrent protection philosophies. This paper proposes the IntelArc system to accurately diagnose series arc faults in dc systems. Inte-lArc combines time-frequency and time-domain extracted features with hidden Markov models (HMMs) to discriminate between nominal transient behavior and arc fault behavior across a variety of operating conditions. Preliminary testing of the system is outlined with results showing that the system has the potential for accurate, generalized diagnosis of series arc faults in dc systems.

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“…The equivalent circuit approach to represent AC-DC converters for fault studies in AC networks was first presented in [24]. But, it appears that most fault studies in DC systems, as reported thus far, tend to use switched circuit for the AC-DC and the DC-DC converters [6], [18], [16], [25], [26].…”

Section: Introductionmentioning

confidence: 99%

Thévenin Equivalent of Voltage-Source Converters for DC Fault Studies

Bahirat

Høidalen

Mork

2016

IEEE Trans. Power Delivery

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The paper presents a simple modulation index dependent thévenin equivalent circuit model of the voltage source converters (VSC) and the associated anti-parallel diode rectifier (APDR). The model derivation uses orthogonal transformation and a transformer analogy to transfer impedances to the DC side of the converter. The paper proposes a switched equivalent representation of a three phase diode rectifier formed due to the antiparallel diodes when VSC switching is inhibited.The proposed model is implemented in ATP-EMTP and simulation results are compared with switched model. The proposed model is shown to under predict the fault currents for pole-ground (PG) faults and to provide nearly exact match for pole-pole (PP) faults. The rectifier equivalent provides increased accuracy in the transient region with the inclusion of the source inductance. A multiterminal DC (MTDC) system model is used to study effects of aggregation which gives increased accuracy of the equivalent circuit. It is shown that the MTDC system simulation with proposed thévenin equivalent is about 3 times faster than fullswitched circuit simulation for a time step of 5 µs. The MTDC system simulation with the thévenin equivalent circuit is still accurate and 126 times faster when the time step is increased to 750 µs.

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DC Protection on the Electric Ship

Cited by 19 publications

References 11 publications

Protection Scheme for DC Microgrid Distribution System

Protection Scheme for DC Microgrid Distribution System

Diagnosis of Series DC Arc Faults—A Machine Learning Approach

Thévenin Equivalent of Voltage-Source Converters for DC Fault Studies

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