EPE Association: EPE 2018 - DS1e: Power Electronics in Transmission and Distribution Systems

EPE 2018 - DS1e: Power Electronics in Transmission and Distribution Systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2018 ECCE Europe - Conference > EPE 2018 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2018 - DS1e: Power Electronics in Transmission and Distribution Systems

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   Control algorithm for an active ground fault current compensator in ungrounded distribution networks
By Pavel SMIRNOV [View]
[Download]

Abstract: Single-phase ground fault is one of the most frequent faults in distribution networks. Despite theability of the continuous operation with a sustained fault, the ground fault current is to be compensateduntil it would be cleared or self-cleared. This work proposes a control algorithm for an active groundfault current compensator. The algorithm is based on the system decomposition into positive, negativeand zero sequence. The ground fault current value determination procedure is discussed. The synthesisof the proposed algorithm, the controller tuning process and simulation results are presented.

   Control Concept for Parallel Interleaved Three-Phase Converters with Decoupled Balancing Control
By Johannes BURKARD [View]
[Download]

Abstract: The parallel operation of multiple switches, modules or complete converters allows the realization of power electronic systems with high output currents. However, an equal distribution of the total current between the parallel modules has to be ensured to avoid excessive losses and the saturation of individual inductors. In this paper, a novel current balancing control approach is presented that is decoupled from the output voltage and current controllers and combines the benefits of an intuitive operation principle, simple controller design and low implementation effort. The analysis, discussion as well as the simulative verification of the concept are exemplarily performed for a three-phase four-wire grid connected 10 kVA converter for smart grid applications.

   Design of a High-Performance Battery Converter System for Providing Synthetic Inertia at Distribution Network Level
By Julian GOLLENSTEDE [View]
[Download]

Abstract: The frequency stability in the electrical supply system is challenged by increasing inertia-free power electronics-based generation capacities. To mitigate this effect, high performance battery convertersystems controlled as virtual synchronous generators can provide synthetic inertia. This paper presentsa system design and a detailed evaluation of this application. An analysis of grid frequencymeasurements is carried out to derive design criteria for the battery converter system's control.Furthermore, experimental results are shown which demonstrate the operation of a virtual synchronousgenerator system.

   High Bandwidth Distributed Secondary Control with Communication Compensation in VSC-based Microgrid
By Rasool HEYDARI [View]
[Download]

Abstract: This paper proposes a novel wireless-based robust communication approach for the high bandwidth distributedsecondary control in parallel operation of voltage source converters (VSCs). This approach isrealized by firstly applying finite control set model predictive control at primary control level, hence, secondarycontrol can be operated in higher bandwidth. Then, a data prediction block is added to secondarycontrol level to compensate for communication deficiencies. Simulation and experimental results showtransient response and the robustness of the proposed approach is far superior to conventional algorithms.

   Loss Characteristics of Modular Multilevel Converter with RC-IGBT for High Voltage DC Transmission
By Xianjin HUANG [View]
[Download]

Abstract: The modular multilevel DC/DC converter, intended for realizing interconnection of DC grids with different voltage levels, is one of the key equipment in DC grids. The fully controlled power device is the core device of the high voltage DC/DC converter, which determines the performance of the convertor system. Compared to the traditional IGBT module, the reverse-conducting IGBT (RC-IGBT) has lower thermal resistance and higher current tolerance with the same package. By controlling the desaturated characteristic of the body diode through the gate of RC-IGBT, the reverse recovery loss can be reduced. In this paper, RC-IGBT is applied to the high voltage MMC DC/DC converter, and a method of desaturated control is proposed to reduce the loss of the converter. The gate desaturation control characteristic of RC-IGBT diode is studied, and the working principle of the sub-module of MMC DC/DC converter is analyzed, and the pulse distribution states of RC-IGBT MMC DC/DC converter are given. The strategy of saturation control based on RC-IGBT sub-module is proposed. Finally, the MATLAB / Simulink software is used to prove the validity of the design,and the loss calculation of the simulation model is carried out. The simulation and calculation results show the effectiveness of the proposed desaturation control method.

   Medium Voltage Single-stage Dual Active Bridge based Solid State Transformer (DABSST)
By Soumik SEN [View]
[Download]

Abstract: This paper introduces a single-stage medium voltage (MV) solid state transformer (SST) based on dual active bridge topology and recently developed high voltage Super-cascode device. A closed loop control system of the output voltage is designed and verified by simulation results. A fully functional SST based on the proposed concept has been developed and tested with an input voltage of 3.6kV and experimental results show unity power factor operation with zero voltage switching of both primary and secondary devices.

   Model Predictive Control Approach for Distributed Hierarchical Control of VSC-based Microgrids
By Rasool HEYDARI [View]
[Download]

Abstract: This paper embeds a high bandwidth distributed hierarchical control structure for a power electronicbased ac microgrid. Conventionally, hierarchical linear control loops are applied to control the gridfrequency and voltage. However, they suffer slow dynamic response and high sensitivity to parametervariations. In this paper, high bandwidth control approach realized with a finite control set model predictivecontrol (FCS-MPC) scheme to control multiple voltage source converters (VSCs). Furthermore,droop control and virtual impedance are employed to share active and reactive power. At the upper leveldistributed secondary control can be programmed with much higher bandwidth compare to linearizedcascaded control structures. Simulation and experimental results indicate that voltage and frequencyhave been regulated order of magnitude faster than state of the art.

   Pre-Evaluation of Grid Code Compliance for Power Electronics Inverter Systems in Low-Voltage Smart Grids
By Johannes STÖCKL [View]
[Download]

Abstract: This paper describes the application of controller hardware-in-the-loop (C-HIL) methods within an integrated design framework consisting of power electronics hardware, controller board and software, and high level management system where the grid code compliance of Smart Grid converter systems is pre-evaluated. This framework is used to evaluate a distributed energy resource (DER) converter design to grid code compliance prior to full hardware implementation. The advantage of this approach is that software errors can be identified earlier in the design process, thereby reducing the time to market.

   Separation of Power Electrical Circuits for Different Computation Platforms
By Axel KIFFE [View]
[Download]

Abstract: The increasing complexity of power grids makes hardware-in-the-loop simulation of electrical powersystems more and more interesting for the industry. The simulation models are typically very large andoften have to be split and used on several hardware platforms to allow for efficient computation. Inthis paper, the separation of power electrical systems, which are modeled by the state-space approach,is analyzed to enhance the simulation accuracy and consequently to simplify the splitting procedure.

   SHORT-CIRCUIT CALCULATION IN AC NETWORKS IN CASE OF HVDC STATIONS WITH LINE-COMMUTATED CONVERTERS (LCC)
By Gerd BALZER [View]
[Download]

Abstract: Short-circuit currents are a key measure for the planning of AC high voltage electrical networks. These currents can be calculated according to the IEC standard 60909-0: 02-2016. However, the existing standard does not consider the contribution of HVDC stations. In this paper, the short-circuit contribution of a HVDC system with line-commutated converters (LCC) is investigated and an analytic expression for the short-circuit contribution is proposed for the usage in an updated version of this standard. For that, the single contributions of the LCC HVDC system's parts are examined and the processes are studied taking place during an AC short circuit. With this knowledge, an analytic approximation can be derived and is verified by simulations in EMTDC/PSCAD.

   Simplified converters models for the analysis and simulation of large transmission systems using 100\% power electronics
By Quentin COSSART [View]
[Download]

Abstract: In this paper, a model order reduction method is proposed, to simplify power electronics converters and allow simulating large transmission systems using 100\% power electronics. Unlike existing methods it keeps the system's physical structure, thus making the simulation and the analysis more flexible. This method is validated on a two-converter system and proves to be both conservative and accurate.

   TRANSFORMER INRUSH CURRENTS IN A NPC BASED CONVERTER SYSTEM FOR COLD IRONING APPLICATIONS
By Luis VACCARO [View]
[Download]

Abstract: In this paper, the effects of the transformer inrush currents in a real plant for Cold Ironing, with a power equal to 11 MVA, based on a conversion system using 4 NPC converters in parallel, is presented. The first part describes the plant and the related problems, while in the second part two possible solutions are presented with the support of real measured data.

   Unified Power sharing Control in Hybrid AC/DC Microgrids Employing Synchronous Machine Principle
By Rasool HEYDARI [View]
[Download]

Abstract: Due to the highly developed AC grids and extend merits of DC grid, the future of power system architecture would more likely be a hybrid AC-DC grid. The only method to interconnect these two subgridsis employing power electronic converters. In this paper, a unified power sharing approach based on synchronous machine principle is proposed for Interlinking Converter (IC) in hybrid AC-DC grids. Thisapproach interconnects dc link voltage to ac frequency by emulating the synchronous machine model,and hereby, introducing a proper power sharing between DC and AC sources. Simulations results validatethe effectiveness of the control scheme.

EPE 2018 - DS1e: Power Electronics in Transmission and Distribution Systems
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2018 ECCE Europe - Conference > EPE 2018 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2018 - DS1e: Power Electronics in Transmission and Distribution Systems
	[return to parent folder]

	Control algorithm for an active ground fault current compensator in ungrounded distribution networks By Pavel SMIRNOV	[View] [Download]
Abstract: Single-phase ground fault is one of the most frequent faults in distribution networks. Despite theability of the continuous operation with a sustained fault, the ground fault current is to be compensateduntil it would be cleared or self-cleared. This work proposes a control algorithm for an active groundfault current compensator. The algorithm is based on the system decomposition into positive, negativeand zero sequence. The ground fault current value determination procedure is discussed. The synthesisof the proposed algorithm, the controller tuning process and simulation results are presented.

	Control Concept for Parallel Interleaved Three-Phase Converters with Decoupled Balancing Control By Johannes BURKARD	[View] [Download]
Abstract: The parallel operation of multiple switches, modules or complete converters allows the realization of power electronic systems with high output currents. However, an equal distribution of the total current between the parallel modules has to be ensured to avoid excessive losses and the saturation of individual inductors. In this paper, a novel current balancing control approach is presented that is decoupled from the output voltage and current controllers and combines the benefits of an intuitive operation principle, simple controller design and low implementation effort. The analysis, discussion as well as the simulative verification of the concept are exemplarily performed for a three-phase four-wire grid connected 10 kVA converter for smart grid applications.

	Design of a High-Performance Battery Converter System for Providing Synthetic Inertia at Distribution Network Level By Julian GOLLENSTEDE	[View] [Download]
Abstract: The frequency stability in the electrical supply system is challenged by increasing inertia-free power electronics-based generation capacities. To mitigate this effect, high performance battery convertersystems controlled as virtual synchronous generators can provide synthetic inertia. This paper presentsa system design and a detailed evaluation of this application. An analysis of grid frequencymeasurements is carried out to derive design criteria for the battery converter system's control.Furthermore, experimental results are shown which demonstrate the operation of a virtual synchronousgenerator system.

	High Bandwidth Distributed Secondary Control with Communication Compensation in VSC-based Microgrid By Rasool HEYDARI	[View] [Download]
Abstract: This paper proposes a novel wireless-based robust communication approach for the high bandwidth distributedsecondary control in parallel operation of voltage source converters (VSCs). This approach isrealized by firstly applying finite control set model predictive control at primary control level, hence, secondarycontrol can be operated in higher bandwidth. Then, a data prediction block is added to secondarycontrol level to compensate for communication deficiencies. Simulation and experimental results showtransient response and the robustness of the proposed approach is far superior to conventional algorithms.

	Loss Characteristics of Modular Multilevel Converter with RC-IGBT for High Voltage DC Transmission By Xianjin HUANG	[View] [Download]
Abstract: The modular multilevel DC/DC converter, intended for realizing interconnection of DC grids with different voltage levels, is one of the key equipment in DC grids. The fully controlled power device is the core device of the high voltage DC/DC converter, which determines the performance of the convertor system. Compared to the traditional IGBT module, the reverse-conducting IGBT (RC-IGBT) has lower thermal resistance and higher current tolerance with the same package. By controlling the desaturated characteristic of the body diode through the gate of RC-IGBT, the reverse recovery loss can be reduced. In this paper, RC-IGBT is applied to the high voltage MMC DC/DC converter, and a method of desaturated control is proposed to reduce the loss of the converter. The gate desaturation control characteristic of RC-IGBT diode is studied, and the working principle of the sub-module of MMC DC/DC converter is analyzed, and the pulse distribution states of RC-IGBT MMC DC/DC converter are given. The strategy of saturation control based on RC-IGBT sub-module is proposed. Finally, the MATLAB / Simulink software is used to prove the validity of the design,and the loss calculation of the simulation model is carried out. The simulation and calculation results show the effectiveness of the proposed desaturation control method.

	Medium Voltage Single-stage Dual Active Bridge based Solid State Transformer (DABSST) By Soumik SEN	[View] [Download]
Abstract: This paper introduces a single-stage medium voltage (MV) solid state transformer (SST) based on dual active bridge topology and recently developed high voltage Super-cascode device. A closed loop control system of the output voltage is designed and verified by simulation results. A fully functional SST based on the proposed concept has been developed and tested with an input voltage of 3.6kV and experimental results show unity power factor operation with zero voltage switching of both primary and secondary devices.

	Model Predictive Control Approach for Distributed Hierarchical Control of VSC-based Microgrids By Rasool HEYDARI	[View] [Download]
Abstract: This paper embeds a high bandwidth distributed hierarchical control structure for a power electronicbased ac microgrid. Conventionally, hierarchical linear control loops are applied to control the gridfrequency and voltage. However, they suffer slow dynamic response and high sensitivity to parametervariations. In this paper, high bandwidth control approach realized with a finite control set model predictivecontrol (FCS-MPC) scheme to control multiple voltage source converters (VSCs). Furthermore,droop control and virtual impedance are employed to share active and reactive power. At the upper leveldistributed secondary control can be programmed with much higher bandwidth compare to linearizedcascaded control structures. Simulation and experimental results indicate that voltage and frequencyhave been regulated order of magnitude faster than state of the art.

	Pre-Evaluation of Grid Code Compliance for Power Electronics Inverter Systems in Low-Voltage Smart Grids By Johannes STÖCKL	[View] [Download]
Abstract: This paper describes the application of controller hardware-in-the-loop (C-HIL) methods within an integrated design framework consisting of power electronics hardware, controller board and software, and high level management system where the grid code compliance of Smart Grid converter systems is pre-evaluated. This framework is used to evaluate a distributed energy resource (DER) converter design to grid code compliance prior to full hardware implementation. The advantage of this approach is that software errors can be identified earlier in the design process, thereby reducing the time to market.

	Separation of Power Electrical Circuits for Different Computation Platforms By Axel KIFFE	[View] [Download]
Abstract: The increasing complexity of power grids makes hardware-in-the-loop simulation of electrical powersystems more and more interesting for the industry. The simulation models are typically very large andoften have to be split and used on several hardware platforms to allow for efficient computation. Inthis paper, the separation of power electrical systems, which are modeled by the state-space approach,is analyzed to enhance the simulation accuracy and consequently to simplify the splitting procedure.

	SHORT-CIRCUIT CALCULATION IN AC NETWORKS IN CASE OF HVDC STATIONS WITH LINE-COMMUTATED CONVERTERS (LCC) By Gerd BALZER	[View] [Download]
Abstract: Short-circuit currents are a key measure for the planning of AC high voltage electrical networks. These currents can be calculated according to the IEC standard 60909-0: 02-2016. However, the existing standard does not consider the contribution of HVDC stations. In this paper, the short-circuit contribution of a HVDC system with line-commutated converters (LCC) is investigated and an analytic expression for the short-circuit contribution is proposed for the usage in an updated version of this standard. For that, the single contributions of the LCC HVDC system's parts are examined and the processes are studied taking place during an AC short circuit. With this knowledge, an analytic approximation can be derived and is verified by simulations in EMTDC/PSCAD.

	Simplified converters models for the analysis and simulation of large transmission systems using 100\% power electronics By Quentin COSSART	[View] [Download]
Abstract: In this paper, a model order reduction method is proposed, to simplify power electronics converters and allow simulating large transmission systems using 100\% power electronics. Unlike existing methods it keeps the system's physical structure, thus making the simulation and the analysis more flexible. This method is validated on a two-converter system and proves to be both conservative and accurate.

	TRANSFORMER INRUSH CURRENTS IN A NPC BASED CONVERTER SYSTEM FOR COLD IRONING APPLICATIONS By Luis VACCARO	[View] [Download]
Abstract: In this paper, the effects of the transformer inrush currents in a real plant for Cold Ironing, with a power equal to 11 MVA, based on a conversion system using 4 NPC converters in parallel, is presented. The first part describes the plant and the related problems, while in the second part two possible solutions are presented with the support of real measured data.

	Unified Power sharing Control in Hybrid AC/DC Microgrids Employing Synchronous Machine Principle By Rasool HEYDARI	[View] [Download]
Abstract: Due to the highly developed AC grids and extend merits of DC grid, the future of power system architecture would more likely be a hybrid AC-DC grid. The only method to interconnect these two subgridsis employing power electronic converters. In this paper, a unified power sharing approach based on synchronous machine principle is proposed for Interlinking Converter (IC) in hybrid AC-DC grids. Thisapproach interconnects dc link voltage to ac frequency by emulating the synchronous machine model,and hereby, introducing a proper power sharing between DC and AC sources. Simulations results validatethe effectiveness of the control scheme.