scholarly journals Protection Method Based on Wavelet Entropy for MMC-HVDC Overhead Transmission Lines

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 678
Author(s):  
Weibo Huang ◽  
Guomin Luo ◽  
Mengxiao Cheng ◽  
Jinghan He ◽  
Zhao Liu ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Transmission Systems ◽  
Wavelet Entropy ◽  
Overhead Lines ◽  
Time Frequency ◽  
Protection Method ◽  
Distribution Features ◽  
The Impact

Recent technological developments in modular multilevel converter-based high-voltage direct current (MMC-HVDC) transmission systems have shown significant advantages over the traditional HVDC and two-level voltage source converter (VSC) transmission systems. However, there are a lack of studies on the protection methods for MMC-HVDC overhead lines where the protection method should be able to provide a fast and accurate response and be able to identify lightning strikes. In this paper, a wavelet entropy-based protection method is proposed. Due to the capability of revealing time–frequency distribution features, the proposed protection method combines wavelet and entropy to identify the time–frequency characteristics of different faults. Simulation results show that the proposed method can accurately and quickly determine the types of faults or disturbances with appropriate noise tolerance. In addition, the impact of the ground resistor and fault distance on the performance of the proposed method is studied.

scholarly journals Reliability Assessment of a Multi-State HVDC System by Combining Markov and Matrix-Based Methods

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3097
Author(s):  
Roberto Benato ◽  
Antonio Chiarelli ◽  
Sebastian Dambone Sessa
Keyword(s):  
Current System ◽  
Estimation Method ◽  
Reliability Estimation ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Hvdc System ◽  
Critical Elements ◽  
The Matrix ◽  
The Impact

The purpose of this paper is to highlight that, in order to assess the availability of different HVDC cable transmission systems, a more detailed characterization of the cable management significantly affects the availability estimation since the cable represents one of the most critical elements of such systems. The analyzed case study consists of a multi-terminal direct current system based on both line commutated converter and voltage source converter technologies in different configurations, whose availability is computed for different transmitted power capacities. For these analyses, the matrix-based reliability estimation method is exploited together with the Monte Carlo approach and the Markov state space one. This paper shows how reliability analysis requires a deep knowledge of the real installation conditions. The impact of these conditions on the reliability evaluation and the involved benefits are also presented.

scholarly journals A Selective Fault Clearing Scheme for a Hybrid VSC-LCC Multi-Terminal HVdc System

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3554
Author(s):  
Naushath M. Haleem ◽  
Athula D. Rajapakse ◽  
Aniruddha M. Gole ◽  
Ioni T. Fernando
Keyword(s):  
High Capacity ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Circuit Breakers ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Clearing Functions ◽  
Transmission Structure ◽  
The Impact

A selective fault clearing scheme is proposed for a hybrid voltage source converter (VSC)-line commutated converter (LCC) multi-terminal high voltage direct current (HVdc) transmission structure in which two small capacity VSC stations tap into the main transmission line of a high capacity LCC-HVdc link. The use of dc circuit breakers (dc CBs) on the branches connecting to VSCs at the tapping points is explored to minimize the impact of tapping on the reliability of the main LCC link. This arrangement allows clearing of temporary faults on the main LCC line as usual by force retardation of the LCC rectifier. The faults on the branches connecting to VSC stations can be cleared by blocking insulated gate bipolar transistors (IGBTs) and opening ac circuit breakers (ac CB), without affecting the main line’s performance. A local voltage and current measurement based fault discrimination scheme is developed to identify the faulted sections and pole(s), and trigger appropriate fault recovery functions. This fault discrimination scheme is capable of detecting and discriminating short circuits and high resistances faults in any branch well before 2 ms. For the test grid considered, 6 kA, 2 ms dc CBs can easily facilitate the intended fault clearing functions and maintain the power transfer through healthy pole during single-pole faults.

scholarly journals A Review of LCC-HVDC and VSC-HVDC Technologies and Applications

2016 ◽  
Vol 1 (3) ◽  
pp. 68 ◽  
Author(s):  
Oluwafemi Emmanuel Oni ◽  
Kamati I. Mbangula ◽  
Innocent E. Davidson
Keyword(s):  
Direct Current ◽  
Transmission Lines ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
High Voltage Direct Current ◽  
Operational Characteristics ◽  
Current Transmission ◽  
Converter Topologies ◽  
Control Capability ◽  
Ac Transmission

High Voltage Direct Current (HVDC) systems has been an alternative method of transmitting electric power from one location to another with some inherent advantages over AC transmission systems. The efficiency and rated power carrying capacity of direct current transmission lines highly depends on the converter used in transforming the current from one form to another (AC to DC and vice versa). A well configured converter reduces harmonics, increases power transfer capabilities, and reliability in that it offers high tolerance to fault along the line. Different HVDC converter topologies have been proposed, built and utilised all over the world. The two dominant types are the line commutated converter LCC and the voltage source converter VSC. This review paper evaluates these two types of converters, their operational characteristics, power rating capability, control capability and losses. The balance of the paper addresses their applications, advantages, limitations and latest developments with these technologies.

scholarly journals A new passive islanding detection technique for different zones in utility grid

2021 ◽  
Vol 9 (3B) ◽  
Author(s):  
Yasser Ahmed Elshrief ◽  
◽  
A. D. Asham ◽  
Belal Ahmed Abozalam ◽  
Sameh Abd-Elhaleem ◽  
...  
Keyword(s):  
Large Scale ◽  
Detection Algorithm ◽  
Rate Of Change ◽  
Voltage Source ◽  
Small Scale ◽  
Voltage Source Converter ◽  
Islanding Detection ◽  
Utility Grid ◽  
Convenient Technique ◽  
The Impact

Distributed generation (DG) has reformed the meaning of traditional generation of power from large-scale to small-scale generation. The main issue of connecting the DG to the utility grid is the detection of unintended islanding. This paper shows the impact of the islanding phenomenon in the case of grid-connected photovoltaic arrays and how to develop a convenient technique to detect this phenomenon. A passive islanding detection algorithm is proposed for all types of DGs by varying and analyzing the DC-link voltage for voltage source converter in the photovoltaic inverter. The proposed algorithm is applied on the low and medium voltage scales. Furthermore, a comparison for applying the proposed technique with resistance load on the two scales is presented. In addition, the proposed technique for anti-islanding protection is performed and compared with a lot of techniques such as underfrequency, overfrequency, and rate of change of frequency according to the detection time of islanding. The simulation results using MATLAB/ SIMULINK platform illustrate the effectiveness of the proposed method.

scholarly journals Dynamic analysis of voltage angle droop controlled HVDC systems in curative congestion management scenarios

2019 ◽  
Vol 217 ◽  
pp. 01004
Author(s):  
Yang Zhou ◽  
Stefan Dalhues ◽  
Ulf Häger
Keyword(s):  
Power System ◽  
Dynamic Behavior ◽  
Transmission Lines ◽  
Power Flow ◽  
Congestion Management ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Management Scenarios ◽  
Hvdc System ◽  
Good Ability

The integration of the voltage-source converter based high voltage direct current (VSC-HVDC) system makes the set-point of its active power adaptive to the changes in the power flow, and contributes to the curative congestion management. To further exploit the dynamic behavior of a hybrid AC/DC power system in curative congestion management scenarios, this paper investigates a novel control scheme for voltage angle droop controlled HVDC (VAD-HVDC) systems. The proposed scheme to alleviate the circuit overload is estimated firstly by calculating the severity index when the power flow changes under N-1 situations. Then the voltage angle controlled HVDC system is applied on the modified IEEE 39-bus 10-machine test power system for the time-domain simulation. The dynamic behavior in the HVDC station validates that the VAD control can stabilize the DC voltage and possess a good ability against interference. In addition, the dynamic characteristics analysis on the AC transmission lines proves that the hybrid AC/DC system integrated with the VAD controlled HVDC system are in possession of good stability after the N-1 contingency event. The VAD controller employed in the HVDC system is capable of effective congestion management to mitigate the critical loadings on the transmission lines.

scholarly journals Improved Two-Level Voltage Source Converter for High-Voltage Direct Current Transmission Systems

2017 ◽  
Vol 5 (4) ◽  
pp. 1670-1686 ◽  
Author(s):  
Grain Philip Adam ◽  
Ibrahim Abdelsalam ◽  
John Edward Fletcher ◽  
Lie Xu ◽  
Graeme M. Burt ◽  
...  
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Transmission Systems ◽  
High Voltage Direct Current ◽  
Current Transmission
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