DC Line Ground Fault Detection Scheme for Line Commutated Converter High Voltage Direct Current Connected to Renewable Energy Source

2018 ◽  
Vol 10 (2) ◽  
pp. 267-274
Author(s):  
Hyun Jae Yoo ◽  
Myong-Chul Shin ◽  
Jae Hyeong Lee ◽  
Young Kwan Choi
Keyword(s):  
Energy Source ◽  
Renewable Energy Source ◽  
Renewable Energy ◽  
High Voltage ◽  
Direct Current ◽  
Detection Scheme ◽  
High Voltage Direct Current ◽  
Ground Fault ◽  
Dc Line ◽  
Ground Fault Detection

scholarly journals Tansient fault analysis of a VSC-based multi-terminal HVDC scheme

2020 ◽  
Author(s):  
◽  
Sindisiwe Cindy Malanda
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Reactive Power ◽  
Short Circuit ◽  
Critical Time ◽  
Fault Analysis ◽  
Fault Current ◽  
Dc Voltage ◽  
High Voltage Direct Current ◽  
Ground Fault

A multiterminal HVDC system includes the connection of different HVDC terminals to a common grid. Most of the MTDC networks are realized in voltage source converter (VSC) high voltage direct current (HVDC). Over long distances, HVDC transmission is preferred to high voltage direct current (HVAC). Furthermore, HVDC is subjected to minimal harmonics oscillation problems due to the absence of frequency. HVDC enables the interconnection of systems at different frequencies, and the system becomes free of angular stability problems. VSCs employ insulated gate bipolar transistors (IGBTs) switches, and High-frequency pulse width modulation is used to operate the IGBTs in order to achieve high-speed control of active and reactive power. The growth of MTDC networks may require a new type of VSCs topology, which is resilient and efficient to dc and ac network fault. This research investigation focuses on the transient dc-side fault analysis in a two-level Monopolar VSC- Based Multi-Terminal HVDC Scheme consisting of four asynchronous terminals sharing a rated 400kV DC-grid was carried out in PSCAD software. During dc-side fault analysis, a pole-to-ground fault was taken into consideration as it’s more likely to occur, although it is less severe compared to pole-to-pole. The converters are interconnected through 100 km dc cables placed 0.5 gm apart and at a depth of 1.5 m underground. It was observed that during the steady-state analysis, the dc voltage in the grid was maintained at the rated value 400 kV, the currents measured at the converters bus was 0.5 kA, and the current flowing through the cables was 0.25 kA. Under the fault condition, the dc voltage drop needs to be maintained to a closed range to avoid the grid to collapse. The voltage droop technique was incorporated in the dc voltage controller to keep the dc voltage at the narrow range. Depending on the value and nature of ground fault resistance, the fault current magnitude varies, and distance variation along the cable has a significant contribution in the fault current. It is observed that fault close to the converter (5 km’s measured 9 kA) results in high fault currents compared to fault away from the converter (50 km’s measured 7.8 kA). The protection design of the VSC needs to be able to detect whether its ground fault or short circuit since the location of the fault needs to be identified and repaired. Another observation made when the fault is inserted 50 kms away from the converter, meaning the fault is at the center of the two converters, the outcome results in high currents in both converters. The isolation of the fault should be fast and selective as the critical time is very short. The dc circuit breakers are mostly recommended to be used as primary protection; however, different protection techniques need to be incorporated with dc circuit breaker in order to quickly identify, select and reliable isolate the faulted line. Moreover, the protection should be able to isolate the line before the fault reaches the maximum fault current to avoid the damage in the converter components.

Study of Interleaved Double Dual Boost Converter for Renewable Energy Source System

2014 ◽  
Vol 931-932 ◽  
pp. 910-914
Author(s):  
Matheepot Phattanasak ◽  
Wattana Kaewmanee ◽  
Jean Philippe Martin ◽  
Serge Pierfederici ◽  
Bernard Davat
Keyword(s):  
Energy Source ◽  
Renewable Energy Source ◽  
Renewable Energy ◽  
High Voltage ◽  
Photovoltaic Cell ◽  
Boost Converter ◽  
Voltage Gain ◽  
Negative Current ◽  
High Voltage Gain ◽  
Energy Application

This paper presents an interleaved double dual boost converter used in renewable energy application, for example, photovoltaic cell. The converter is interesting because its high voltage gain property. Its operating functions in the possible cases are detailed. Moreover, the presence of negative current in a certain operating point is investigated. The validation of the proposed system is done through experimental results.

Is there a grid-connected effect of grid infrastructure on renewable energy generation? Evidence from China's upgrading transmission lines

2021 ◽  
pp. 0958305X2110310
Author(s):  
Yongpei Wang ◽  
Chao Xu ◽  
Pinghong Yuan
Keyword(s):  
Energy Source ◽  
Power Generation ◽  
Renewable Energy Source ◽  
Renewable Energy ◽  
High Voltage ◽  
Power Grid ◽  
Power Grids ◽  
Grid Infrastructure ◽  
Extra High Voltage ◽  
Ultra High Voltage

China has built the world's largest power infrastructure. Those upgrading power grid facilities not only contribute to providing enough end-used energy for the world's factories, but also offering a basic guarantee for the clean strategy of Building a Beautiful China proposed by the Chinese government. The national grid system supported by extra-high voltage and ultra-high voltage grids as the backbone makes it possible for a non-dispatchable renewable energy source to be connected to the national grid and transmitted to terminal consumers in load centers. The aim of this paper is to test whether China's advanced power grids have played a positive role in promoting power generation of intermittent renewable energy source. A novel nonlinear estimation named panel smoothing transition regression is introduced to capture heterogeneous effects of grid-connecting renewable energy source across regions. The empirical results show that whereas power grid infrastructure generally enhances power generation of renewable energy source and consumption in energy bases and load centers, the effects change across different voltage levels of power grids. The extra-high voltage power grids show strong support for grid-connecting renewable energy source, while the effect of ultra-high voltage power grids is unexpectedly insignificant. The extra-high voltage power grids have not yet become the backbone of the national grid, which is the main reason for the inadequate grid-connected renewable energy source to the ultra-high voltage power grids, indicating the importance of upgrading the power grid infrastructure.

scholarly journals Wavelet transform as a postprocessing diagnostic tool for fault identifications of high-voltage direct current transmission system

FACETS ◽  
2017 ◽  
Vol 1 (1) ◽  
pp. 17-26 ◽  
Author(s):  
P. Sanjeevikumar ◽  
Frede Blaabjerg
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Diagnostic Tool ◽  
Simulation Software ◽  
Discrete Wavelet ◽  
Transmission Network ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Ground Fault ◽  
Current Transmission

This short communication focuses on exploiting the inherent advantages of discrete wavelet transformation (DWT) as a diagnostic tool for post-processing and for identifying the faults that occur in the standard high-voltage direct-current (HVDC) transmission network. In particular, a set of investigations are developed and examined for single-line-to-ground fault on the generation and on the load side converter, and DC-link fault. For this purpose, a standard 12-pulse line-commutated converter (LCC)-HVDC transmission network along with the DWT algorithm is numerically modeled in the MATLAB/PLECS simulation software. Furthermore, in this paper, a set of designed faulty conditions are predicted using the output of DWT and the results of numerical simulation are presented. Results are in good agreement with expectations to prove that DWT is an effective tool for fault diagnostics.

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