Contribution Mechanism and Impact Analysis of AC System at the Diode Natural Commutation and Conduction Stage During Bipolar Short-Circuit Fault for Single-Terminal VSC-Based DC Distribution Networks

2021 ◽  
Author(s):  
Zhi-hua Zhang ◽  
Kun Wang ◽  
Yilong Zhao ◽  
Hao Wang
Keyword(s):  
Impact Analysis ◽  
Short Circuit ◽  
Distribution Networks ◽  
Dc Distribution ◽  
Short Circuit Fault

scholarly journals Online Estimation of Short-Circuit Fault Level in Active Distribution Network

2020 ◽  
Vol 10 (11) ◽  
pp. 3812
Author(s):  
Xiaohui Wang ◽  
Peng Wang ◽  
Yunbo Wang ◽  
Fang Shi
Keyword(s):  
Equivalent Circuit ◽  
Short Circuit ◽  
Distribution Network ◽  
Estimation Method ◽  
Short Circuit Current ◽  
Distribution Networks ◽  
Measurement Unit ◽  
Online Estimation ◽  
Active Distribution Network ◽  
Short Circuit Fault

The potential short-circuit current in active distribution network features time-variance with the increasing distributed generations. This feature makes the online estimation of fault level necessary. In this paper, a novel online estimation method is proposed to be implemented by either phasor measurement unit (PMU) or the measurements from protection relays. The equivalent circuit of the radial distribution network with distributed generators (DGs), e.g., wind turbines and photovoltaic cells, is derived with necessary simplifications. The natural disturbances downstream are used to evaluate the parameters of the equivalent circuit so that the potential fault level can be estimated in advance of the actual fault occurrence. A fuzzy logic identifier is presented to rank the confidence of the measurements incurred by the disturbance and to distinguish the qualified disturbance to launch the estimation. The mechanism based on multi-measurements and confidence indices was applied, to improve the accuracy. A typical distribution network in the United Kingdom (UK) with DGs was taken, as an example, to validate the proposed method under various load fluctuation. The results confirm the effectiveness of the proposed method, which is suitable for online estimation of short-circuit fault level in active distribution networks.

Short-Circuit Fault Protection of a Low Voltage DC Distribution System using Superimposed Current Components

2017 ◽  
Vol 31 (10) ◽  
pp. 86-94
Author(s):  
Saeed Zaman Jamali ◽  
Muhammad Omer Khan ◽  
Syed Basit Ali Bukhari ◽  
Muhammad Mehdi ◽  
Gi-Hyeon Gwon ◽  
...  
Keyword(s):  
Distribution System ◽  
Low Voltage ◽  
Short Circuit ◽  
Fault Protection ◽  
Dc Distribution ◽  
Short Circuit Fault

Artificial Neural Network Application in Optimal Coordination of Directional Overcurrent Protective Relays in Electrical Mesh Distribution Network

2015 ◽  
Vol 785 ◽  
pp. 48-52 ◽  
Author(s):  
Osaji Emmanuel ◽  
Mohammad Lutfi Othman ◽  
Hashim Hizam ◽  
Muhammad Murtadha Othman
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Response Time ◽  
Short Circuit ◽  
Distribution Networks ◽  
Test System ◽  
Wrong Response ◽  
Optimal Coordination ◽  
Artificial Neural ◽  
Short Circuit Fault

Directional Overcurrent relays (DOCR) applications in meshed distribution networks (MDN), eliminate short circuit fault current due to the topographical nature of the system. Effective and reliable coordination’s between primary and secondary relay pairs ensures effective coordination achievement. Otherwise, the risk of safety of lives and installations may be compromised alongside with system instability. This paper proposes an Artificial Neural Network (ANN) approach of optimizing the system operation response time of all DOCR within the network to address miscoordination problem due to wrong response time among adjacent DOCRs to the same fault. A modelled series of DOCRs in a simulated IEEE 8-bus test system in DigSilent Power Factory with extracted data from three phase short circuit fault analysis adapted in training a custom ANN. Hence, an improved optimized time is produced from the network output to eliminate miscoordination among the DOCRs.

Research on the Network Based Protection to Settle the Distribution Networks Three-Phase Short-Circuit Faults with Distributed Generators

2014 ◽  
Vol 496-500 ◽  
pp. 1457-1463
Author(s):  
Yan Xu ◽  
Qin Cheng Yuan ◽  
Xiao Yun Huang ◽  
Lan Jiang
Keyword(s):  
Distributed Generation ◽  
Short Circuit ◽  
Current Source ◽  
Distribution Networks ◽  
Control Mode ◽  
Equivalent Model ◽  
Network Protection ◽  
Fault Ride Through ◽  
Three Phase ◽  
Short Circuit Fault

A model is established to research on the applicability of network protection in theory. In this model, distributed power generation with constant power (PQ) control mode which is equivalent to a voltage control current source is taken as the research object. Fault ride-through control theory is used to analyze the influence on the network protection exerted by three-phase short-circuit fault. In this paper, the equivalent model of the distributed generation is offered firstly. Then the three-phase short-circuit fault characteristics are illustrated based on the equations of the access points voltage and the distributed generations current. In the end, a simulation model is built to verify that the network protection can be applied to settle the three-phase short-circuit fault in the distributed network with distributed generation.

scholarly journals Influence Analysis of Current Limiting Reactor on Pole-to-Pole Short Circuit Fault in DC Distribution System

2021 ◽  
Vol 256 ◽  
pp. 01032
Author(s):  
Zhenyu Wang ◽  
Shouxiang Wang ◽  
Qi Liu ◽  
Chunyu Zhang ◽  
Qianyu Zhao ◽  
...  
Keyword(s):  
Distribution System ◽  
Short Circuit ◽  
Fault Current ◽  
Capacitor Discharge ◽  
Fault Type ◽  
Dc Distribution ◽  
Current Limiting ◽  
Fault Mechanism ◽  
Short Circuit Fault ◽  
A Current

With the development of power electronic technology, flexible DC distribution system has gradually become a research hotspot. Pole-to-pole short circuit fault is the most serious fault type in DC distribution system. When pole-to-pole short circuit fault occurs in DC side, it will produce a large fault current, which will cause serious harm to DC distribution system. Therefore, it is urgent to install current limiting reactor to limit fault over-current. Aiming at the DC distribution system based on half bridge MMC, this paper analyses the fault mechanism and fault characteristics of pole-to-pole short circuit fault, studies the current limiting effect of the installation position and capacity of current limiting reactor on fault current, and carries out simulation verification in PSCAD / EMTDC platform. The analysis and simulation results show that installing a current limiting reactor at the outlet of the DC side can reduce the peak value of capacitor discharge current, and installing a current limiting reactor at the outlet of the AC side can reduce the overall amplitude of fault current.

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