scholarly journals Master-Slave Approach for a Multi-terminal VSC-HVDC Systems Connected Offshore Wind Farm

2021 ◽  
Vol 297 ◽  
pp. 01045
Author(s):  
Mohamed Amine Kazi ◽  
Radouane Majdoul ◽  
Nadia Machkour ◽  
Adnane El-alami ◽  
Ibrahim Baraka
Keyword(s):  
Wind Farm ◽  
Energy Transition ◽  
Operating Conditions ◽  
Offshore Wind ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Global Challenge ◽  
Bus Voltage ◽  
Abnormal Operating Conditions

The world is facing today the global challenge of energy transition since countries need more and more energy to grow their economy on a planet where resources are limited and poorly distributed. The integration of renewable energies and especially offshore wind energy into high voltage direct current (VSC-HVDC) transmission systems demonstrates great flexibility and reliability. In this paper, a control strategy for a multi-terminal VSC-HVDC system based on Master-Slave approach is proposed to automatically share the real power variation and stabilize the DC bus voltage in presence of abnormal operating conditions.

scholarly journals Advanced Fault Ride-through Strategy by an MMC HVDC Transmission for Off-Shore Wind Farm Interconnection

2019 ◽  
Vol 9 (12) ◽  
pp. 2522
Author(s):  
Lee ◽  
Yoo ◽  
Yoon ◽  
Jang
Keyword(s):  
Control Strategy ◽  
Power Plants ◽  
Wind Farm ◽  
Dc Voltage ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Fault Ride Through ◽  
Doubly Fed ◽  
Grid Side

In order to solve the problems brought upon by off-shore wind-power plants, it is important to improve fault ride-through capability when an on-shore fault occurs in order to prevent DC overvoltage. In this paper, a coordinated control strategy is implemented for a doubly-fed induction generator (DFIG)-based off-shore wind farm, which connects to on-shore land by a modular multilevel converter (MMC)-based high voltage direct current (HVDC) transmission system during an on-shore fault. The proposed control strategy adjusts the DC voltage of the off-shore converter to ride through fault condition, simultaneously varying off-shore AC frequency. The grid-side converter detects the frequency difference, and the rotor-side converter curtails the output power of the DFIG. The surplus energy will be accumulated at the rotor by accelerating the rotor speed and DC link by rising DC voltage. By the time the fault ends, energy stored in the rotor and energy stored in the DC capacitor will be released to the on-shore side to restore the normal transmission state. Based on the control strategy, the off-shore wind farm will ride through an on-shore fault with minimum rotor stress. To verify the validity of the proposed control strategy, a DFIG-based wind farm connecting to the on-shore side by an MMC HVDC system is simulated by PSCAD with an on-shore Point of Common Coupling side fault scenario.

scholarly journals Real Time Simulation of Wind Farm Connected MMC-HVDC System

2020 ◽  
Vol 8 (6S) ◽  
pp. 46-52
Keyword(s):  
Real Time ◽  
Wind Farm ◽  
Computing Time ◽  
Offshore Wind ◽  
Modular Multilevel Converter ◽  
Offshore Wind Farm ◽  
Multilevel Converter ◽  
Real Time Simulation ◽  
Hvdc System ◽  
Time Simulation

Real time simulators play a major role in R&D of Offshore wind farm connected modular multilevel converter (MMC)-HVDC system. These simulators are used for testing the actual prototype of controllers or protection equipment required for the system under study. Modular multilevel converter comprises of number of sub modules (SMs) like Half/ full bridge cells. While computing time domain Electromagnetic transients (EMTs) with the system having large number of SMs pose a great challenge. This computational burden will be more when simulated in real time. To overcome this, several authors proposed equivalent mathematical model of MMC. This paper proposes the real time simulation start-up of offshore wind farm connected modular multilevel converter (MMC)-HVDC system. This paper also describes about how the above said systems is simulated in OPAL-RT based Hypersim software.

scholarly journals Minimum Short Circuit Ratio Requirement for MMC-HVDC Systems Based on Small-Signal Stability Analysis

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3283 ◽  
Author(s):  
Zheren Zhang ◽  
Liang Xiao ◽  
Guoteng Wang ◽  
Jian Yang ◽  
Zheng Xu
Keyword(s):  
Reactive Power ◽  
Short Circuit ◽  
Small Signal ◽  
Small Signal Stability ◽  
Ratio Requirement ◽  
Planning Stage ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
High Voltage Direct Current ◽  
Signal Stability

This paper determines the minimum short circuit ratio (SCR) requirement for a modular multilevel converter based high-voltage direct current (MMC-HVDC) transmission systems. Firstly, a simplified model of MMC is introduced; the MMC is represented by its AC and DC side equivalent circuit. Next, by linearizing the MMC subsystem and the DC network subsystem, the deduction of the small-signal models of MMC subsystem, the small-signal model of the DC network and MMC-HVDC are carried out successively. Thirdly, the procedure for determining the minimum SCR requirement of MMC-HVDC is described. Finally, case studies are performed on a two-terminal MMC-HVDC system under four typical control schemes. The results show that the restraint factors for the rectifier MMC is predominantly the voltage safety limit constraint, and the restraint factors for the inverter MMC are mainly the phase locked loop (PLL) or the outer reactive power controller. It is suggested that the minimum SCR requirement for the sending and the receiving systems should be 2.0 and 1.5 in the planning stage.

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 Fault Ride Through Strategy for Offshore Wind Farm Integration System via MMC-HVDC

2018 ◽  
Vol 173 ◽  
pp. 03083
Author(s):  
Zhang Lijun ◽  
Zhong Yujun ◽  
Chen Rui ◽  
Sun Yikai ◽  
Zhang Jing ◽  
...  
Keyword(s):  
Wind Farm ◽  
Control Strategies ◽  
Fault Isolation ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Integration System ◽  
Fault Ride Through ◽  
Bus Voltage ◽  
Grid Side ◽  
Wind Farm Integration

When offshore wind power is transmitted to ac grid through MMC-HVDC, the current and voltage will be quite different from those in traditional ac grid during grid side fault. This paper sets up an offshore wind farm integration system via MMC-HVDC and designs control strategies for each unit in the system. The fault ride through strategy of the system is proposed and its effectiveness has been verified. Thus, the AC bus voltage on wind farm side will stay stable during AC side fault. Once the chopper resistance is set properly, the output power and current of the wind farm can basically remain unchanged, which can successfully achieve fault isolation. The simulation results based on PSCAD have verified the theoretical analysis.

An Approach to Improving Performance of the dc Filter in HVDC Transmission System

2011 ◽  
Vol 48-49 ◽  
pp. 183-186 ◽  
Author(s):  
Ming Li
Keyword(s):  
South China ◽  
Transmission System ◽  
Operating Conditions ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
Filter Performance

The Gui-Guang HVDC system in south china scheme with interconnections to the 500kV transmission to Guizhou and to Guangdong can exhibits, under certain operating conditions, the percussion of the dc filters impedance resonance problems. The analysis explains the dc filters impedance resonance. The influence of changing the dc filter parameters is also studied. Finally, an assessment is made for improve the dc filter performance

scholarly journals Validation of Numerical Models of the Offshore Wind Turbine From the Alpha Ventus Wind Farm Against Full-Scale Measurements Within OC5 Phase III

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Wojciech Popko ◽  
Amy Robertson ◽  
Jason Jonkman ◽  
Fabian Wendt ◽  
Philipp Thomas ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Farm ◽  
Operating Conditions ◽  
Offshore Wind ◽  
Phase Iii ◽  
Offshore Wind Turbine ◽  
Discrete Fourier Transforms ◽  
Simulation Tools ◽  
Axial Forces

Abstract The main objective of the Offshore Code Comparison Collaboration Continuation, with Correlation (OC5) project is validation of aero-hydro-servo-elastic simulation tools for offshore wind turbines (OWTs) through comparison of simulated results to the response data of physical systems. Phase III of the OC5 project validates OWT models against the measurements recorded on a Senvion 5M wind turbine supported by the OWEC Quattropod from the alpha ventus offshore wind farm. The following operating conditions of the wind turbine were chosen for the validation: (1) idling below the cut-in wind speed, (2) rotor-nacelle assembly (RNA) rotation maneuver below the cut-in wind speed, (3) power production below and above the rated wind speed, and (4) shutdown. A number of validation load cases were defined based on these operating conditions. The following measurements were used for validation: (1) strains and accelerations recorded on the support structure and (2) pitch, yaw, and azimuth angles, generator speed, and electrical power recorded from the RNA. Strains were not directly available from the majority of the OWT simulation tools; therefore, strains were calculated based on out-of-plane bending moments, axial forces, and cross-sectional properties of the structural members. The simulation results and measurements were compared in terms of time series, discrete Fourier transforms, power spectral densities, and probability density functions of strains and accelerometers. A good match was achieved between the measurements and models setup by OC5 Phase III participants.

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