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 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.

Real power regulation design for multi-terminal VSC-HVDC systems

2013 ◽  
Vol 3 (2) ◽  
Author(s):  
Guo-Jie Li ◽  
Si-Ye Ruan ◽  
Tek Lie
Keyword(s):  
Control Strategy ◽  
Control Mode ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Real Power ◽  
The Real ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Power Regulation ◽  
Regulation Functions

AbstractA multi-terminal voltage-source-converter (VSC) based high voltage direct current (HVDC) system is concerned for its flexibility and reliability. In this study, a control strategy for multiple VSCs is proposed to auto-share the real power variation without changing control mode, which is based on “dc voltage droop” power regulation functions. With the proposed power regulation design, the multiple VSCs automatically share the real power change and the VSC-HVDC system is stable even under loss of any one converter while there is no overloading for any individual converter. Simulation results show that it is effective to balance real power for power disturbance and thus improves operation reliability for the multi-terminal VSC-HVDC system by the proposed control strategy.

scholarly journals Research on Serial VSC-LCC Hybrid HVdc Control Strategy and Filter Design Scheme

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2260
Author(s):  
Fan Cheng ◽  
Lijun Xie ◽  
Zhibing Wang
Keyword(s):  
Reactive Power ◽  
Filter Design ◽  
Control Strategies ◽  
Short Circuit ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Level Control ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Design Scheme

This paper investigated the characteristics of a novel type of hybrid high voltage direct current (HVdc) converter, which is composed by line commutated converter series with voltage source converter. The system and valve level control strategies are introduced, which can provide ac system voltage support. A novel filter design scheme composed by resonant filers for hybrid HVdc are also proposed, which can decrease the capacity of reactive power compensation equipment without deteriorate harmonic characteristics. The ac voltage of HVdc fluctuation level caused by transmitted power variation will be effectively reduced, with the coordination between filter design scheme and converter control. In addition, the influence of ac grid strength is also analyzed by equivalent source internal impedance represented by short circuit ratio (SCR). Finally, the +800 kV/1600 MW hybrid HVdc system connecting two ac grids under different SCR cases are studied, and the PSCAD/EMTDC simulation results have validated the effectiveness for proposed strategy.

A Fault Diagnosis Method in VSC-HVDC Simulation System Based on BRBP Neural Networks

2013 ◽  
Vol 860-863 ◽  
pp. 2269-2274
Author(s):  
Hao Yang Cui ◽  
Yong Peng Xu ◽  
Jun Jie Yang ◽  
Jun Dong Zeng ◽  
Zhong Tang
Keyword(s):  
Neural Networks ◽  
Fault Diagnosis ◽  
Back Propagation ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Current Transmission ◽  
Diagnosis Method ◽  
Dc Current

As the feature of faulty signal in high voltage direct current transmission technology based on voltage source converter (VSC-HVDC) system is complicated to extract and its difficult to carry on the fault diagnosis. On the basis of the PSCAD simulation model of VSC-HVDC system, the DC current faulty signal is analyzed. Then, the wavelet analysis method was adopted to extract the eigenvector of faulty signal, and combined with method of Bayesian regularization back-propagation (BRBP) neural networks, the system fault was identified. The simulation results show that the method is more efficiently and more rapidly than the adding momentum BP neural network on the VSC-HVDC system faults diagnosing.

scholarly journals Interoperability of Modular Multilevel and Alternate Arm Converters in Hybrid HVDC Systems

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1363
Author(s):  
Harith R. Wickramasinghe ◽  
Pingyang Sun ◽  
Georgios Konstantinou
Keyword(s):  
Control Structure ◽  
State Of The Art ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Control Functions ◽  
Complex Hybrid

This paper demonstrates the interoperability of an emerging alternate arm converter (AAC) with the state-of-the-art modular multilevel converter (MMC) in high-voltage direct current (HVDC) systems based on a hybrid VSC-HVDC system. The paper also showcases the parameter derivation of the hybrid HVDC system and its detailed control structure. The study provides preliminary steps towards detailed analysis of AAC interoperability in complex hybrid dc grid configurations. A detailed set of results based on the 800 MVA hybrid voltage source converter (VSC)-HVDC system showcases the interoperability performance of the AAC under different operating scenarios and verifies its associated control functions.

scholarly journals Pilot Protection Based on Amplitude of Directional Travelling Wave for Voltage Source Converter-High Voltage Direct Current (VSC-HVDC) Transmission Lines

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2021 ◽  
Author(s):  
Lingtong Jiang ◽  
Qing Chen ◽  
Wudi Huang ◽  
Lei Wang ◽  
Yu Zeng ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Travelling Waves ◽  
Travelling Wave ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Protection Scheme ◽  
Fault Resistance ◽  
Pilot Protection

This paper presents a novel pilot protection scheme of DC cable line in voltage-source-converter (VSC) based multi-terminal DC (MTDC) grids, which utilizes a novel phase-mode transformation to decouple the bipolar DC cable current into six mode and it uses the stationary wavelet transform to extract the modulus maxima of fault initial traveling waves current (FITWC). With accurate amplitude and polarities of the FITWC being collected from the fault-detection devices located at each terminal, the proposed scheme can correctly determine the faulty segment and the faulty pole. In this paper, the ratio of amplitudes between sixth mode forward and backward travelling wave currents is used to judge the faulty segment and the polarity of fifth mode forward travelling wave current is used to identify the faulty pole. A four-terminal VSC-based MTDC grid was built in PSCAD/EMTDC to evaluate the performance of the fault-protection scheme. Simulation results for different cases demonstrate that the proposed protection scheme is robust against noise, and has been tested successfully for fault resistance of up to 400 Ω. Since the scheme merely needs the characteristics of FITWCs, the practical difficulties of detecting subsequent travelling waves are avoided. Moreover, only the state signal is needed to send to the other side in proposed scheme, so low communication speed can satisfy the requirement of relay protection and it does not need the data synchronization seriously.

scholarly journals Comparison of cable models for time domain simulations

2017 ◽  
Author(s):  
W.Z. El-Khatib ◽  
Joachim Holbøll ◽  
Tonny W. Rasmussen ◽  
Stephan Vogel
Keyword(s):  
Power Systems ◽  
Large Scale ◽  
Offshore Wind ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Offshore Wind Power ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Wind Power Integration ◽  
Dc Fault

<p>This paper will look at dc cable transient modelling issues for voltage source converter (VSC) based high voltage direct current (HVDC) transmission systems,<br />which is getting evermore admired for large-scale offshore wind power integration. A simple mathematical π-equivalent cable model is presented and explained. The<br />model is compared to the detailed cable models with different degrees of accuracy found in PSCAD/EMTDC. The models are analyzed and tested using simulations of<br />dc fault conditions and energization. These studies are helpful for the protection system design of large-scale renewable energy power systems to realize a reliable multi-terminal dc transmission system for the future. </p>

Dynamic Behavior Study of a VSC-HVDC System with SPWM Command Subjected to an Important Variation of Load

2017 ◽  
Vol 33 ◽  
pp. 76-83
Author(s):  
Kokou Thophile Houngan ◽  
Richard Gilles Agbokpanzo ◽  
Kizito Codja ◽  
Pierre Aguemon ◽  
Christophe Espanet
Keyword(s):  
Dynamic Behavior ◽  
Pulse Width Modulation ◽  
Electrical Energy ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Technical Parameters ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Important Variation ◽  
Behavior Study

To interconnect sources of production, it is necessary to watch that the technical parameters as tension, frequency and phase shift of the sources of production are equal. In Benin, it is difficult for the company in charge of the production and of the transport of the electricity to interconnect the production coming from Nigeria and that coming from Ghana because all the parameters are not equal. It is thus necessary to find a way to interconnect the sources of productions to satisfy not only the request in electrical energy but also to insure the continuity of the service and the stability of the electricity network [1,2]. In this work, we studied the dynamic behavior of the Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) system subjected to an important variation of load and commanded by the Sine-triangle Pulse Width Modulation ( SPWM) to improve the quality of the electrical energy. We developed thus first of all the electric model of all the constituents of the system. These models allowed designing easily the control systems of the static converters VSC (the rectifier and the inverter). The simulation of the inverter showed that the rate of distortion of harmonious varied considerably according to the load for important variations of load. The solution brought by this work is the elaboration of a control system to vectorial PWM who improves the rate of distortion of harmonious.

scholarly journals SIMULATION OF VSC BASED HVDC TRANSMISSION SYSTEM FOR THE INTEGRATION OF WINDFARM INTO GRID

2013 ◽  
pp. 19-22
Author(s):  
MAHALAKSHMI. R ◽  
P. USHA
Keyword(s):  
Wind Farms ◽  
Voltage Source ◽  
Modern World ◽  
Voltage Source Converter ◽  
Simulation Studies ◽  
Transmission Systems ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
Ac Transmission ◽  
And Control

Wind energy has huge potential to become major source of renewable energy for the modern world. For integrating wind farms to the AC grid, HVDC transmission systems have several advantages over AC transmission systems. This paper presents the design and control of voltage source converter based HVDC system for integration of wind farms in to AC grid. The designed VSC-HVDC system performance under steady state conditions and various transient conditions are presented. The PSCAD/EMTDC software package is used for the simulation studies.

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