EPE Association: EPE 2014 - LS3f: HVDC FACT's

EPE 2014 - LS3f: HVDC FACT's
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2014 ECCE Europe - Conference > EPE 2014 - Topic 06: Grids and Smart Grids > EPE 2014 - LS3f: HVDC FACT's

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   Dynamic performance of series multiterminal HVDC during AC faults at inverter stations
By XIAOBO YANG, Chunming YUAN, Dawei YAO, Chao YANG, Chengyan YUE [View]
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Abstract: Multiterminal high voltage direct current (MTDC) system can be either a series type or a parallel type. Series MTDC concept is essentially developed from the two-terminal HVDC but with some unique characteristics. In this paper, the AC fault ride through capability of series MTDC is discussed. AC faults at inverter stations, which are connected to electrically separated AC systems, will be highlighted. For an AC fault that happens at one inverter station, the DC voltage of that station may decrease to zero due to commutation failure, while the other inverter stations (the healthy inverters) can still retain power transmission capability to some extent, which will increase the availability of the series MTDC system. However, the current controller design, the voltage dependent current order limiter (VDCOL) logic and the AC system strength will impact on the dynamic performance of series MTDC during AC faults. In this paper, a +800kV/3.2GW 4-terminal line commutated converter (LCC) based series MTDC model is established to study the dynamic performance during AC fault occurs at one inverter. The controller of the series MTDC is designed; the VDCOL logic for series MTDC is developed; simulation results of the dynamic performance during AC faults at the inverter stations are presented.

   Experimental Validation of Autonomous Converter Control in a HVDC Grid
By SHENG WANG, Liang JUN, WHITEHOUSE ROBERT, BARKER CARL [View]
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Abstract: Much research has been done regarding the control and coordination of VSC converters in a MultiterminalHVDC network or grid. Amongst those, one underlying concept is the most common- the DCvoltage droop control.In this paper, the control concept has been further developed to use alternative droop characteristics oneach converter. This approach allows precise converter current regulation during normal operationwhile stabilizes DC voltage during power disturbance.Control algorithms of alterative droop characteristics are provided and interactions of different controlcharacteristics are also analyzed.This concept is validated using both digital simulation (PSCAD/EMTDC) and physical modelling of aHVDC grid using a 4-terminal VSC Physical Simulator. Results obtained from the two simulationplatforms are compared and show good agreement. The feasibility and advantage of using alternativedroop characteristics on each single converter are also validated.

   Practical Aspects of Implementation of Back-to-Back HVDC Schemes without DC Smoothing Reactors
By Radnya MUKHEDKAR, Jose MONTEIRO, Mike LI, Gearoid O'HEIDHIN [View]
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Abstract: The publication discusses implementation of back-to-back line commutated converter schemes without DC smoothing reactors and the associated design considerations. The areas reviewed include steady state performance of the scheme namely AC harmonics due to close DC coupling between the two terminals and dynamic performance i.e. scheme performance for a voltage dip in the inverter end AC system.

   Scalable Shunt Connected HVDC Tap Using the DC Transformer Concept
By Jose MANEIRO, Sarath TENNAKOON, Carl BARKER [View]
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Abstract: This paper describes the concept of a recently proposed scalable DC/DC converter topology applied to a shunt connected HVDC tap. This solution offers some advantages with respect to previously proposed solutions. Two different configurations of the circuit are proposed for interconnection withdifferent HVDC systems. The internal structure of the modular DC/DC converter is presented and a suitable strategy to control the system is investigated in order to achieve soft-switching of the converter semiconductors. The operation is validated using computer simulations, which include a rough estimation of the DC/DC converter power losses.

EPE 2014 - LS3f: HVDC FACT's
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2014 ECCE Europe - Conference > EPE 2014 - Topic 06: Grids and Smart Grids > EPE 2014 - LS3f: HVDC FACT's
	[return to parent folder]

	Dynamic performance of series multiterminal HVDC during AC faults at inverter stations By XIAOBO YANG, Chunming YUAN, Dawei YAO, Chao YANG, Chengyan YUE	[View] [Download]
Abstract: Multiterminal high voltage direct current (MTDC) system can be either a series type or a parallel type. Series MTDC concept is essentially developed from the two-terminal HVDC but with some unique characteristics. In this paper, the AC fault ride through capability of series MTDC is discussed. AC faults at inverter stations, which are connected to electrically separated AC systems, will be highlighted. For an AC fault that happens at one inverter station, the DC voltage of that station may decrease to zero due to commutation failure, while the other inverter stations (the healthy inverters) can still retain power transmission capability to some extent, which will increase the availability of the series MTDC system. However, the current controller design, the voltage dependent current order limiter (VDCOL) logic and the AC system strength will impact on the dynamic performance of series MTDC during AC faults. In this paper, a +800kV/3.2GW 4-terminal line commutated converter (LCC) based series MTDC model is established to study the dynamic performance during AC fault occurs at one inverter. The controller of the series MTDC is designed; the VDCOL logic for series MTDC is developed; simulation results of the dynamic performance during AC faults at the inverter stations are presented.

	Experimental Validation of Autonomous Converter Control in a HVDC Grid By SHENG WANG, Liang JUN, WHITEHOUSE ROBERT, BARKER CARL	[View] [Download]
Abstract: Much research has been done regarding the control and coordination of VSC converters in a MultiterminalHVDC network or grid. Amongst those, one underlying concept is the most common- the DCvoltage droop control.In this paper, the control concept has been further developed to use alternative droop characteristics oneach converter. This approach allows precise converter current regulation during normal operationwhile stabilizes DC voltage during power disturbance.Control algorithms of alterative droop characteristics are provided and interactions of different controlcharacteristics are also analyzed.This concept is validated using both digital simulation (PSCAD/EMTDC) and physical modelling of aHVDC grid using a 4-terminal VSC Physical Simulator. Results obtained from the two simulationplatforms are compared and show good agreement. The feasibility and advantage of using alternativedroop characteristics on each single converter are also validated.

	Practical Aspects of Implementation of Back-to-Back HVDC Schemes without DC Smoothing Reactors By Radnya MUKHEDKAR, Jose MONTEIRO, Mike LI, Gearoid O'HEIDHIN	[View] [Download]
Abstract: The publication discusses implementation of back-to-back line commutated converter schemes without DC smoothing reactors and the associated design considerations. The areas reviewed include steady state performance of the scheme namely AC harmonics due to close DC coupling between the two terminals and dynamic performance i.e. scheme performance for a voltage dip in the inverter end AC system.

	Scalable Shunt Connected HVDC Tap Using the DC Transformer Concept By Jose MANEIRO, Sarath TENNAKOON, Carl BARKER	[View] [Download]
Abstract: This paper describes the concept of a recently proposed scalable DC/DC converter topology applied to a shunt connected HVDC tap. This solution offers some advantages with respect to previously proposed solutions. Two different configurations of the circuit are proposed for interconnection withdifferent HVDC systems. The internal structure of the modular DC/DC converter is presented and a suitable strategy to control the system is investigated in order to achieve soft-switching of the converter semiconductors. The operation is validated using computer simulations, which include a rough estimation of the DC/DC converter power losses.