EPE Association: EPE 2017 - DS3l: Smart Grids, Fault Coordination and Protection of DC Grids

EPE 2017 - DS3l: Smart Grids, Fault Coordination and Protection of DC Grids
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 06: Grids and Smart Grids > EPE 2017 - DS3l: Smart Grids, Fault Coordination and Protection of DC Grids

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   Analysis and Enhanced Topologies of Active-Resonance DC Circuit Breaker
By Mudar ABEDRABBO [View]
[Download]

Abstract: DC circuit breakers are needed in future HVDC grids to provide selectivity in clearing DC faults and to achieve continuous operation of the healthy part of the grid. Standard mechanical circuit breakers as used in AC systems cannot be used in HVDC applications due to the lack of current zero-crossing, which is essential for arc extinction. To use mechanical interrupters for fault current interruption in DC applications, resonant circuits are used to create artificial current zero-crossings, by superimposing the resonant current on the DC current in the circuit breaker. Although the resonant current creates the zero-crossing, it introduces stresses on the mechanical circuit breaker and limits its rating, since the superimposed resonant current possibly introduces large peaks before current interruption.This paper proposes an improved active-resonance DC circuit breaker topology which aims to increase breaker ratings by avoiding these peaks. The improved topology is able to control the direction of resonant current injection, limit internal circuit breaker currents and allows for multiple interruption attempts. The principle of operation and advantages over presently proposed topologies have been verified by simulation results.

   Comparative Analysis and Coordination Study of Bi-Directional Z-Source Breaker with Reclosing Capabilities
By SWATI SAVALIYA [View]
[Download]

Abstract: Recently introduced Bi-directional Z-Source breakers [1] are capable of clearing the short circuit fault within a few microseconds. In this paper, various applications and protection requirements for Bi-directional Z-Source breakers are discussed. Detailed comparison between de-rated AC breakers and Z-Source breakers is discussed. Breaker design criteria are explained with the help of simulation results for the instantaneous surge current and short-circuit protections. Many times faults in the transmission line are temporary. Very few faults are permanent in nature where the breaker has to isolate the faulty line for the maintenance. Therefore, a breaker should be able to perform an operating duty of reclosing and re-breaking. Both topologies discussed in [1] are modified to build reclosing and re-breaking capabilities and simulation results are presented. In addition, coordination of Bi-directional Z-Source breaker (Bi-ZSB) is analyzed in a ring network [6]. Control scheme for locating the fault in a network is proposed. MATLAB simulation study is carried out to verify the breaker performance for coordination in a ring network.

   Coordination of Active Current Limiters and Hybrid Circuit Breakers for a MVDC Link Meshing MVAC Distribution Grids
By Alessio CLERICI [View]
[Download]

Abstract: This paper presents a protection scheme for a medium voltage dc (MVDC) link, that meshes three different MVAC distribution grids through ac/dc power converters. The proposed scheme includes active current limiters, hybrid circuit breakers and a communication layer for the coordination of these protection devices and power converters (logic selectivity). Active current limiters, installed just after dc bulk capacitors of each power converter, ensure fault current limitation in order to protect the power converters until the fault clearance by dc grid protections. The coordination logic among the protection devices is described in this paper, together with notes on the design of those devices. In case of communication failure, the proposed scheme could not guarantee logic selectivity, but it is anyway able to clear the fault. The effectiveness of the proposed protection strategy is validated in a fast transients simulation environment, using detailed model of power electronic converters.

   DC Short Circuit Ride-through Strategy for a Full-Bridge MMC HVDC Transmission System
By Mahmoud FAWZI [View]
[Download]

Abstract: Modular multi-level converters (MMC) are considered a promising topology for HV applications likeHVDC transmission systems. Such systems must be designed to provide high reliability against differenttypes of faults. MMCs using Half-Bridge (HF) cells are well known for lacking the capability to blockshort circuits in the DC link. On the contrary, Full-Bridge (FB) cells can block the short circuit currentin the DC link, they also enable the implementation of Fault Ride-through (FRT) functionalities, as thecells can generate bipolar voltages in this case. This paper presents a DC short circuit fault ride-throughstrategy for HVDC transmission system using an MMC topology with FB cells (FBMMC). Two modesof operation are possible during the fault. In the _rst one, the MMC can support the AC grid with reactivepower, but will not transfer active power. In the second mode, the MMC can transfer active power duringthe fault.

   Implementation of a Power Hardware in the Loop platform with a real time power flow calculation using PSS\E
By Ricard FERRER-SAN-JOSE [View]
[Download]

Abstract: A Power Hardware in the Loop (PHIL) platform implementation for performing real time simulations of electric systems is proposed. The test bench consists of a PSS\E real time power flow calculation in combination with a controlled grid emulator. Experimental results are presented to demonstrate the performance of the platform.

   Real Time Selective Detection of Experimentally Generated DC Series Arcs
By Zhihao LIU [View]
[Download]

Abstract: Localization of series arc faults in dc microgrids is an important requirement to guarantee operational safety and uninterrupted power to end users. In the previous EPE-ECCE proceeding, a theoretical proof was provided for the selective series arc detection using a novel algorithm. In the current paper, the concept is validated by showcasing real time localized detection when series arc is initiated between point of common coupling and one of the parallel loads. Experiments are repeated several times to gain statistical significance to account for the stochastic nature of the arcing phenomenon.

   The Impact of Source and Fault Impedances on Post-Fault Response of Z-Source Circuit Breakers
By Daniel RYAN [View]
[Download]

Abstract: The Z-Source circuit breaker is a type of DC power electronic circuit breaker, which is able to autonomously isolate faults. It uses a circuit of passive components to autonomously commutate the main conducting switch (a thyristor) off during a fault. In order for the ZCB to operate correctly, the thyristor must remain reverse-biased for a defined time period when a fault occurs, i.e., the minimum turn-off constraint must be met. External fault and source impedances modify the time period that the thyristor remains reverse biased, which in turn impacts the fault conditions for which operation is autonomous. In this paper, this effect is investigated analytically through simulation and through experimentation on a hardware prototype.

EPE 2017 - DS3l: Smart Grids, Fault Coordination and Protection of DC Grids
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 06: Grids and Smart Grids > EPE 2017 - DS3l: Smart Grids, Fault Coordination and Protection of DC Grids
	[return to parent folder]

	Analysis and Enhanced Topologies of Active-Resonance DC Circuit Breaker By Mudar ABEDRABBO	[View] [Download]
Abstract: DC circuit breakers are needed in future HVDC grids to provide selectivity in clearing DC faults and to achieve continuous operation of the healthy part of the grid. Standard mechanical circuit breakers as used in AC systems cannot be used in HVDC applications due to the lack of current zero-crossing, which is essential for arc extinction. To use mechanical interrupters for fault current interruption in DC applications, resonant circuits are used to create artificial current zero-crossings, by superimposing the resonant current on the DC current in the circuit breaker. Although the resonant current creates the zero-crossing, it introduces stresses on the mechanical circuit breaker and limits its rating, since the superimposed resonant current possibly introduces large peaks before current interruption.This paper proposes an improved active-resonance DC circuit breaker topology which aims to increase breaker ratings by avoiding these peaks. The improved topology is able to control the direction of resonant current injection, limit internal circuit breaker currents and allows for multiple interruption attempts. The principle of operation and advantages over presently proposed topologies have been verified by simulation results.

	Comparative Analysis and Coordination Study of Bi-Directional Z-Source Breaker with Reclosing Capabilities By SWATI SAVALIYA	[View] [Download]
Abstract: Recently introduced Bi-directional Z-Source breakers [1] are capable of clearing the short circuit fault within a few microseconds. In this paper, various applications and protection requirements for Bi-directional Z-Source breakers are discussed. Detailed comparison between de-rated AC breakers and Z-Source breakers is discussed. Breaker design criteria are explained with the help of simulation results for the instantaneous surge current and short-circuit protections. Many times faults in the transmission line are temporary. Very few faults are permanent in nature where the breaker has to isolate the faulty line for the maintenance. Therefore, a breaker should be able to perform an operating duty of reclosing and re-breaking. Both topologies discussed in [1] are modified to build reclosing and re-breaking capabilities and simulation results are presented. In addition, coordination of Bi-directional Z-Source breaker (Bi-ZSB) is analyzed in a ring network [6]. Control scheme for locating the fault in a network is proposed. MATLAB simulation study is carried out to verify the breaker performance for coordination in a ring network.

	Coordination of Active Current Limiters and Hybrid Circuit Breakers for a MVDC Link Meshing MVAC Distribution Grids By Alessio CLERICI	[View] [Download]
Abstract: This paper presents a protection scheme for a medium voltage dc (MVDC) link, that meshes three different MVAC distribution grids through ac/dc power converters. The proposed scheme includes active current limiters, hybrid circuit breakers and a communication layer for the coordination of these protection devices and power converters (logic selectivity). Active current limiters, installed just after dc bulk capacitors of each power converter, ensure fault current limitation in order to protect the power converters until the fault clearance by dc grid protections. The coordination logic among the protection devices is described in this paper, together with notes on the design of those devices. In case of communication failure, the proposed scheme could not guarantee logic selectivity, but it is anyway able to clear the fault. The effectiveness of the proposed protection strategy is validated in a fast transients simulation environment, using detailed model of power electronic converters.

	DC Short Circuit Ride-through Strategy for a Full-Bridge MMC HVDC Transmission System By Mahmoud FAWZI	[View] [Download]
Abstract: Modular multi-level converters (MMC) are considered a promising topology for HV applications likeHVDC transmission systems. Such systems must be designed to provide high reliability against differenttypes of faults. MMCs using Half-Bridge (HF) cells are well known for lacking the capability to blockshort circuits in the DC link. On the contrary, Full-Bridge (FB) cells can block the short circuit currentin the DC link, they also enable the implementation of Fault Ride-through (FRT) functionalities, as thecells can generate bipolar voltages in this case. This paper presents a DC short circuit fault ride-throughstrategy for HVDC transmission system using an MMC topology with FB cells (FBMMC). Two modesof operation are possible during the fault. In the _rst one, the MMC can support the AC grid with reactivepower, but will not transfer active power. In the second mode, the MMC can transfer active power duringthe fault.

	Implementation of a Power Hardware in the Loop platform with a real time power flow calculation using PSS\E By Ricard FERRER-SAN-JOSE	[View] [Download]
Abstract: A Power Hardware in the Loop (PHIL) platform implementation for performing real time simulations of electric systems is proposed. The test bench consists of a PSS\E real time power flow calculation in combination with a controlled grid emulator. Experimental results are presented to demonstrate the performance of the platform.

	Real Time Selective Detection of Experimentally Generated DC Series Arcs By Zhihao LIU	[View] [Download]
Abstract: Localization of series arc faults in dc microgrids is an important requirement to guarantee operational safety and uninterrupted power to end users. In the previous EPE-ECCE proceeding, a theoretical proof was provided for the selective series arc detection using a novel algorithm. In the current paper, the concept is validated by showcasing real time localized detection when series arc is initiated between point of common coupling and one of the parallel loads. Experiments are repeated several times to gain statistical significance to account for the stochastic nature of the arcing phenomenon.

	The Impact of Source and Fault Impedances on Post-Fault Response of Z-Source Circuit Breakers By Daniel RYAN	[View] [Download]
Abstract: The Z-Source circuit breaker is a type of DC power electronic circuit breaker, which is able to autonomously isolate faults. It uses a circuit of passive components to autonomously commutate the main conducting switch (a thyristor) off during a fault. In order for the ZCB to operate correctly, the thyristor must remain reverse-biased for a defined time period when a fault occurs, i.e., the minimum turn-off constraint must be met. External fault and source impedances modify the time period that the thyristor remains reverse biased, which in turn impacts the fault conditions for which operation is autonomous. In this paper, this effect is investigated analytically through simulation and through experimentation on a hardware prototype.