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  • 1.
    Babazadeh, Davood
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Hohn, Fabian
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Wu, Yimin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Nordström, Lars
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Distributed Two-stage Network Topology Processor for HVDC Grid Operation2017Inngår i: 2017 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, IEEE , 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the results of an analysis of distributed two-stage coordination of network topology processor for HVDC grids. In the first stage of the two-stage processor, the substation topology is analyzed locally using an automated graph based algorithm. Thereafter, a distributed algorithm is proposed to used the neighboring information to realize the grid connectivity. For distributed islanding detection, the connectivity problem is formulated as a set of linear equations and solved iteratively using successive-over-relaxation method. The performance of the proposed methods versus conventional one-stage method has been tested in an islandinv, scenario for a 5-terminal HVDC grid.

  • 2.
    Hohn, Fabian
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Honeth, Nicholas
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Nordström, Lars
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Directional definite-time earth fault protection based on virtual polarisation and COTS components2016Inngår i: IEEE Power and Energy Society General Meeting, IEEE, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper comprises the development of a directional definite-time earth fault protection based on virtual polarisation and Commercial-off-the-Shelf (COTS) components. The earth fault protection is intended to be sensitive for high-resistive and remote faults. The challenge of those type of faults is the low magnitude of the zero-sequence voltage measured at the relay location, which is often used as the polarising quantity for directional sensing. A conventional approach is to use a current transformer (CT) in the neutral-to-ground path of a wye-connected power transformer at the corresponding substation. Since this approach exposes some additional costs and efforts in terms of CT installations and engineering, a virtual polarisation approach has been implemented, which has been introduced by the IEEE Power System Relay Committee. Thus a reliable polarising quantity is gained. The platform architecture has been design based on standardised hardware and software products, considered as COTS components. This effort has been made in order to yield a cost-efficient solution as well as to reduce the time-to-market of the development process. In the end the functional performance of the protection system has been tested utilising a hardware-in-the-loop (HIL) approach.

  • 3.
    Hohn, Fabian
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Nordström, Lars
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Data Models and Protocol Mapping for Reduced Communication Load in Substation Automation with High Sampling Rate Protection Applications2018Inngår i: 2018 IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids (SmartGridComm), Institute of Electrical and Electronics Engineers (IEEE), 2018, artikkel-id 8587426Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In digital substations measurements between instrument transformers and protection systems are exchanged via an Ethernet-based process-level network using the Sampled Value (SV) protocol. At the same time, new protection applications, based on time-domain or travelling-wave signal information, require very high sampling rates, which increases the communication load on the network significantly. The increase of the communication load can be reduced through the concept of Distributed Signal Processing Units (DSPU). This paper proposes data models and suitable protocol mappings for such DSPUs and analyses their impact on the process-level network. The results are compared with the SV approach specified in IEC 61869–9 for digital interfaces of instrument transformers. It is shown that the DSPU concept can reduce the required network bandwidth in the case of high sampling rate protection applications.

  • 4.
    Hohn, Fabian
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Rabuzin, Tin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Wang, Jianping
    Nordström, Lars
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Distributed signal processing units for centralised substation protection and control2018Inngår i: The Journal of Engineering, ISSN 1872-3284, E-ISSN 2051-3305, Vol. 2018, nr 15, s. 1223-1228Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Substation automation systems are characterised by a high degree of functional integration, which can lead to a centralised substation protection and control (CPC) architecture. Most CPC architectures utilise merging units to interface with current and voltage transformers, which causes a high-communication load on the process bus in case of large substations. This study proposes a CPC architecture based on distributed signal processing units (DSPUs) to overcome those drawbacks by publishing the results of the signal processing algorithms directly. The reduction of the communication load through the usage of DSPUs has been shown in a case study, which uses a 16-bay transmission substation topology as a reference.

  • 5.
    Hohn, Fabian
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Wang, Jianping
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Nordström, Lars
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Design of a Distributed Signal Processing Unit for Transmission Line Protection in a Centralized Substation Protection Architecture2018Inngår i: IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society, Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 138-144Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Travelling-wave and time-domain-based protection functions provide significant response time improvements over conventional phasor-based protection functions in power systems. These types of protection functions require very high sampling rates in the order of several hundreds of kHz. This paper proposes a novel centralized substation protection architecture (CPC) based on distributed signal processing units (DSPU) that enables the deployment of these high sampling rate applications in digital substations utilizing an Ethernet-based process-level network. The design of the DSPU is elaborated, and its signal processing algorithms are discussed. Moreover, the performance of the DSPU is analysed through dynamic tests and verified through a numerical electromaanetic transient simulation.

  • 6.
    Jahn, Ilka
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Bessegato, Luca
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Björk, Joakim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Hohn, Fabian
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Norrga, Staffan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Svensson, Niklas
    Svenska Kraftnät, Sweden.
    Sharifabadi, Kamran
    Equinor ASA, Norway.
    Despouys, Olivier
    Réseau de Transport d'Electricité (RTE), France.
    A Proposal for Open-Source HVDC Control2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Future multiterminal high-voltage direct-current (HVDC) grids are considered an enabling technology to efficiently integrate large amounts of renewable energy into the existing grid. However, already in today’s existing point-to-point HVDC links, harmonic interaction issues and instabilities related to the controland protection system of the converters have been reported. The converter control software is usually black-boxed and problems are therefore solved in close cooperation with the HVDC vendor. This paper aims to provide a starting point for a discussion onan open-source HVDC control system. In particular, it covers the control design including technical and non-technical aspects. The open-source approach can be useful to solve current as wellas future control-related problems, both in point-to-point links as well as in multiterminal and multivendor HVDC grids.

  • 7.
    Jahn, Ilka
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Hohn, Fabian
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Norrga, Staffan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Impact of measurement and communication aspects on protection of multi-terminal DC grids2018Inngår i: IET - The Journal of Engineering, E-ISSN 2051-3305Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increased demand for renewable energy generation requires the higher flexibility of transmission systems. This requirement together with technical progress in high-voltage DC technology has resulted in the ambition to build large-scale multi-terminal DC grids. To achieve this goal, vendor interoperability is considered a key element. Standards exist for AC systems, but not for DC systems. This work discusses and evaluates the suitability of AC standards for DC systems. As a result, a different view on substation architecture is developed and two communication protocols are suggested for further investigation in this context.

  • 8.
    Jahn, Ilka
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Hohn, Fabian
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Norrga, Staffan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Impact of Measurement and Communication on Protection of MTDC Grids2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The increased demand for renewable energy generation requires higher flexibility of transmission systems. This requirement together with technical progress in high-voltage direct-current (HVDC) technology have resulted in the ambition to build large-scale multi-terminal DC (MTDC) grids. To achieve this goal, vendor interoperability is considered a key element. Standards exist for AC systems,but not for DC systems. This work discusses and evaluates the suitability of AC standards for DC systems. As a result, a different view on substation architecture is developed and two communication protocols are suggested for further investigation in this context.

  • 9.
    Yiming, Wu
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Xiao, Y.
    Hohn, Fabian
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Nordström, Lars
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Wang, J.
    Zhao, W.
    Bad Data Detection Using Linear WLS and Sampled Values in Digital Substations2018Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 33, nr 1, s. 150-157, artikkel-id 7867789Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Smart Grids employ intelligent control applications that require high quality data: fast, secure, and error free. Several researchers have focused on providing techniques for low latency and secured data links for these applications. Bad data detection is however generally provided only at the central level due to limitations in legacy technologies employed in many substations. With the introduction of IEC61850 data sharing within the substation becomes more flexible and transparent allowing more sophisticated management of data quality. Hence, this paper proposes a substation level bad data detection algorithm to facilitate also these types of requirements from applications. The algorithm is based on automatically detecting the substation topology by parsing standard substation description files and online state of circuit breakers and disconnectors. By applying linear weighted least square based state estimation algorithm, bad data from failing current transformers (CT) can be detected. By conducting the verification of different types of bad data, the results show the output of bad data detection algorithm provides higher accuracy than output from both measurement and protective CT in both static and faulty situations.

1 - 9 of 9
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  • html
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