scholarly journals A Novel Overcurrent Suppression Strategy during Reclosing Process of MMC-HVDC

2019 ◽  
Vol 9 (9) ◽  
pp. 1737 ◽  
Author(s):  
Bin Jiang ◽  
Yanfeng Gong
Keyword(s):  
Transmission Lines ◽  
Short Circuit ◽  
Current Method ◽  
Short Circuit Current ◽  
Simulation Software ◽  
Fault Current ◽  
Overhead Lines ◽  
Hvdc System ◽  
Electromagnetic Transient Simulation ◽  
Current Calculation

A modular multilevel converter based high-voltage DC (MMC-HVDC) system has been the most promising topology for HVDC. A reclosing scheme is usually configured because temporary faults often occur on transmission lines especially when overhead lines are used, which often brings about an overcurrent problem. In this paper, a new fault current limiter (FCL) based on reclosing current limiting resistance (RCLR) is proposed to solve the overcurrent problem during the reclosing process. Firstly, a mesh current method (MCM) based short-circuit current calculation method is newly proposed to solve the fault current calculation of a loop MMC-HVDC grid. Then the method to calculate the RCLR is proposed based on the arm current to limit the arm currents to a specified value during the reclosing process. Finally, a three-terminal loop MMC-HVDC test grid is constructed in the widely used electromagnetic transient simulation software PSCAD/EMTDC and the simulations prove the effectiveness of the proposed strategy.

Study on a New Setting Method of Distance Relay with Superconducting Fault Current Limiter Adapt in the Grid

2012 ◽  
Vol 588-589 ◽  
pp. 471-474
Author(s):  
Jun Mei ◽  
Bin Liu ◽  
Jian Yong Zheng ◽  
Lei Yao
Keyword(s):  
Transmission Lines ◽  
Single Phase ◽  
Short Circuit ◽  
Impedance Measurement ◽  
Simulation Software ◽  
Fault Current ◽  
Fault Current Limiter ◽  
Distance Protection ◽  
Superconducting Fault Current Limiter ◽  
Current Limiter

Considerable attention is given towards developing Superconducting fault current limiter (SFCL) due to increasing short circuit levels in transmission lines, which itself imposes further changes on the measured impendence at the relaying point and causes significant impact on the lines’ relay protection, especially on the distance protection as the single-phase grounding fault occurs. In this paper, resistive superconducting fault current limiter connected to the grid is studied as the model to analysis how SFCL affects the grounded short-circuit impedance relay’s setting, then an new setting method of distance protection for the SFCL-equipped line is proposed. Finally, a power system model is built to analysis the theory by PSCAD / EMTDC simulation software. The results show that in the condition of using the impedance relays’ new setting method, impedance measurement error is greatly reduced, SFCL and line distance protection can work in coordination with each other properly.

scholarly journals Impact of Momentary Cessation Voltage Level in Inverter-Based Resources on Increasing the Short Circuit Current

2019 ◽  
Vol 11 (4) ◽  
pp. 1153 ◽  
Author(s):  
Namki Choi ◽  
Bohyun Park ◽  
Hwanhee Cho ◽  
Byongjun Lee
Keyword(s):  
Power Systems ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Fault Current ◽  
Test Results ◽  
Voltage Level ◽  
Fault Currents ◽  
Current Calculation ◽  
The Impact

This study analyzed the impact of varying the momentary cessation (MC) voltage level on the short circuit current of inverter-based resources (IBRs). To analyze the impact of the IBR MC function on the short circuit current, this paper proposes an advanced IBR model for fault current calculation to reflect its fault characteristics and a scheme for analyzing the influence of MC on the short circuit current. Based on the proposed methods, the authors conducted case studies using planning data from the Korea Electric Power Corporation (KEPCO). The influence of MC was investigated on the IBRs located at the southwest side of the KEPCO systems by screening the fault currents while varying the MC voltage. This paper demonstrates that the minimum MC voltage level needed for the fault current not to exceed the circuit breaker (CB) capacity can be proposed through analyzing the impact of MC voltage level on the short circuit current. The test results based on the proposed scheme showed that the short circuit current to power systems could not violate CB capacity if IBRs adjusted the MC voltage level higher than the lowest MC voltage level.

The Development of a Graphical Open-Ended Integrative Platform for Short-Circuit Calculation and Relay Setting of Power System

2012 ◽  
Vol 241-244 ◽  
pp. 1802-1811
Author(s):  
Zhi Bo Li ◽  
Peng Gao ◽  
Jian Sheng Ma ◽  
Yong Sheng Yan
Keyword(s):  
Power System ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Simulation Software ◽  
Target System ◽  
Practical Applications ◽  
Short Circuit Calculation ◽  
Topology Information ◽  
Current Calculation ◽  
Report Document

To improve the efficiency and accuracy of relay setting calculation of power system, this paper proposed and developed a schematized and open-ended software platform in integrative relay setting. Through the advanced development of the Visio software, the graphical input of the target system topology and component parameters are made possible. The platform can automatically generate PSCAD simulation model according to the topology information and device parameters through an interface program to PSCAD, and use this power system simulation software to improve the accuracy of short-circuit current calculation. With the help of the Bookmark mechanism of WORD software, the platform provides a setting template with general protection components, which forms the basis to realize the open-ended platform. The platform also uses the API interface provided by WORD software to automatically generate the final relay protection setting report document according to the results of short-circuit current calculation and the selected protection setting components. This paper gives in detail the overall framework of the proposed platform, as well as the principle and practice of all the above parts. Moreover, the validity and practicality in improving the automation degree of the relay setting of power plant are shown through practical applications.

scholarly journals The Way of Reducing Current Values in Optical Ground Wires at Asymmetrical Faults on Overhead Transmission Lines

2016 ◽  
Vol 11 (1) ◽  
pp. 13-20
Author(s):  
Georgiy Egamnazarov
Keyword(s):  
Cross Section ◽  
Transmission Lines ◽  
Conclusive Evidence ◽  
Fault Current ◽  
Overhead Lines ◽  
Optical Cable ◽  
Electric Power Grid ◽  
Three Phase ◽  
Wire Steel ◽  
Wire System

Abstract Given the fact that the installing costs of an optical ground wire on overhead lines directly depend on its cross-section, which in turn depends on the level of fault current it should withstand, in order to reduce these current values in the optical ground wire, I suggested performing its isolated descents from the end towers of the line with its transition to an optical cable. The research was carried out on the example of a 500 kV overhead line in the National Electric Power Grid. The Method of Symmetrical Components for calculating asymmetrical fault currents was not used; therefore, calculations were carried out on the base of presenting the line as a multi-wire system for the considered case as a five-wire system (optical ground wire, steel ground wire, and three phase wires). Such approach allows taking into account the initial asymmetry of the line parameters and modeling any kind of asymmetrical faults. The analyses of calculated results were performed. The conclusive evidence that the optical ground wire isolated descents from the end towers of the line give the possibility of reducing the level of maximal fault current distribution values in it and therefore its cross section, is presented.

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