| 1. |
- Chaffey, Geraint, et al.
(författare)
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Demonstration of Multi-vendor Protection Systems for Multiterminal VSC-HVDC Networks
- 2021
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Ingår i: 2021 IEEE Madrid PowerTech, PowerTech 2021 - Conference Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This paper outlines the demonstration of partially selective and fully selective HVDC protection systems using a simulated industrial case study HVDC network, hardware HVDC protection IED prototypes, and simulated HVDC circuit breaker models. A summary of results are presented demonstrating the performance of the protection IEDs and indicating successful operation of the overall HVDC protection system according to system-level indicators. The presented results are intended to increase confidence that HVDC protection systems for multivendor HVDC networks are near ready for full-scale industrial implementation.
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| 2. |
- Chaffey, Geraint, et al.
(författare)
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Design of backup protection for the DC interconnection of adjacent point-to-point HVDC systems
- 2022
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Ingår i: Proceedings 16th International Conference on Developments in Power System Protection, DPSP 2022. - : Institution of Engineering and Technology (IET). ; , s. 25-30
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In order to provide additional flexibility in future power systems, it could be beneficial to connect existing point-to-point highvoltage direct-current (HVDC) systems at the DC-side into a multiterminal network. Such a network would allow increased operational flexibility, continued operation in case of maintenance, and could reduce the end-to-end losses in the overall system. The protection of such a system, however, poses interesting challenges with constraints which differ slightly from typical HVDC grid protection studies. This paper focuses on the trade-offs surrounding the backup protection strategy following failure of a DC circuit breaker in the primary protection role. For this particular application, where a control retrofit should be avoided, the focus is on enabling quicker recovery rather than attempting to maintain continuous operation on a charged and healthy network. Therefore, the functional requirements on the backup switchgear are in some respects reduced compared to that required for primary protection. The benefits of reduced voltage switchgear for this backup protection application are therefore investigated.
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| 3. |
- Chaffey, Geraint, et al.
(författare)
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Requirements for functional testing of HVDC protection IEDs
- 2019
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Konferensbidrag (refereegranskat)abstract
- Development of Intelligent Electronic Devices (IED) for HVDC protection is underway, driven in part by the prospective demands of future multiterminal HVDC systems. There is, however, no consensus on how to test the functionality of an HVDC protection IED. Successful operation of a future multivendor HVDC protection system requires functional specifications and harmonised test procedures for protection system components, including the protection IED. This paper presents an introduction to functional testing methods for HVDC protection IEDs. Evaluating the protection algorithm characteristic using synthetic waveforms is first performed, i.e. ’functional type testing’. Given that test procedures are in part dependent on the protection algorithm, tests are developed and presented for several algorithms. The behaviour of the IED in a power system simulation is then examined during generalised yet representative fault transients, i.e. equivalent to ’dynamic validation type testing’ of AC protection algorithms. The combination of functional and dynamic validation type testing allows the generalised functionality of the IED to be evaluated - testing the algorithm, hardware and software implementation, and overall performance. To provide examples of test procedures, an open-source HVDC IED prototype is tested in a hardware-in-the-loop configuration using a real-time simulator. The operation and accuracy of the protection characteristics are first examined, before the IED performance under representative waveforms is determined. Through tests of several non-unit line protection algorithms, it is shown that, depending on the algorithm applied, the IED is dependable for simulated faults within the protection zone, and secure during external faults. Moreover,the test configurations and procedures required to evaluate the functionality and the criteria for success are developed.
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| 4. |
- Chaffey, Geraint, et al.
(författare)
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The Impact of Point-to-Point VSC-HVDC Protection on Short-Term AC System Voltage
- 2018
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Ingår i: 2018 IEEE pes innovative smart grid technologies conference europe (ISGT-EUROPE). - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- Whilst point-to-point HVDC systems are presently protected from DC-side faults using circuit breakers at the AC-side of the converter stations, converters are unable to provide reactive power support to the AC system during the fault clearance. Implementing DC circuit breakers within the HVDC system could result in several benefits, including the near-continuous provision of reactive power to the AC systems. This paper compares HVDC system protection sequences using AC-side and DC-side protection, and evaluates the impact of these protection strategies on the AC voltage under varying AC-system configurations and varying power flow conditions.
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| 5. |
- Cowan, Ian, et al.
(författare)
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Demonstration of Partially Selective HVDC Grid Protection System with Hardware-in-the-loop IEDs
- 2020
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Ingår i: IET Conference Publications. - : Institution of Engineering and Technology.
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Konferensbidrag (refereegranskat)abstract
- This paper aims to demonstrate a partially selective protection strategy for multiterminal VSC-HVDC systems using a simulated industrial case study network. In order to increase confidence that such a protection strategy would be suitable for implementation on a future network, this paper uses hardware protection intelligent electronic devices (IED) prototypes from industry and academia, HVDC circuit breaker models that have been developed in collaboration with manufacturers, and a realistic case study network. The tests performed within this study are used to evaluate the performance of the protection IED in a realistic system, and examine the operation of the partially selective protection strategy at the system level. Results presented indicate that each IED achieved fast fault detection,reliable discrimination, and that the circuit breaker models were able to successfully isolate the faulted circuit, indicating the success of the partially selective protection strategy.
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| 6. |
- Jahn, Ilka, et al.
(författare)
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A holistic method for optimal design of HVDC grid protection
- 2021
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Ingår i: Electric power systems research. - : Elsevier BV. - 0378-7796 .- 1873-2046. ; 196
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Tidskriftsartikel (refereegranskat)abstract
- Protection system design for high-voltage direct-current (HVDC) grids using DC circuit breakers (DCCBs) is not straightforward. Both hardware parameters, such as line inductors and DCCBs, as well as software parameters, such as protection threshold settings and protection margins, have to be taken into account and interact. Previous studies focused on the impact of specific parameters (e.g., line inductors) while other parameters (e.g., maximum DCCB currents) were checked manually for compliance with constraints. This paper presents a new holistic method for HVDC grid protection design. The approach is no longer exclusively based on parameter sweeps but solves HVDC grid protection as a classic optimization problem with an optimization goal and constraints. Electromagnetic transient (EMT) simulations are embedded into the optimization tool such that the system dynamic response is taken into account. Results for two example test cases and two example optimization goals are provided. For instance, the method can achieve a reduced sum of line inductors compared to an initial guess. The proposed method is useful to find a more optimally designed HVDC protection system, and practical because it makes sure that the constraints (e.g., maximum DCCB current, no converter blocking and large protection margins) are fulfilled.
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| 7. |
- Jahn, Ilka, et al.
(författare)
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An Architecture for a Multi-Vendor VSC-HVDC Station With Partially Open Control and Protection
- 2022
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 10, s. 13555-13569
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Tidskriftsartikel (refereegranskat)abstract
- High voltage direct current (HVDC) grids are envisioned for large-scale grid integration of renewable energy sources. Upon realization, components from multiple vendors have to be coordinated and interoperability problems can occur. To address these problems, a multi-vendor HVDC system can benefit from a partially open control and protection system. Unwanted interactions can be investigated and solved more easily in partially open software compared to when applying black-boxed and vendor-specific software. Although a partially open approach offers these advantages, practical aspects, such as the implementation in a real station architecture, have to be addressed carefully. This paper covers this important topic, first by reviewing the required control and protection functions and second by discussing the choice for certain open and closed software parts, their implementation in physical units as well as the required communication and interfaces. The result from this discussion is a first proposal of a station architecture for a multi-vendor HVDC system using partially open control and protection. This architecture will be a helpful starting point to industry and academia working with research and harmonization on this topic as ad-hoc solutions in terms of practical aspects can be avoided.
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| 8. |
- Jahn, Ilka, et al.
(författare)
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An Open-Source Protection IED for Research and Education in Multiterminal HVDC Grids
- 2020
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Ingår i: IEEE Transactions on Power Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8950 .- 1558-0679. ; 35:4, s. 2949-2958
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Tidskriftsartikel (refereegranskat)abstract
- The integration of large amounts of renewable energy will require multiterminal high-voltage direct-current (MTDC) grids to reliably transport the energy over long distances. However, before building an MTDC grid, a functional protection system design is needed. Realistic and industrial studies are required to validate the functionality of such a system. In addition, further academic research as well as education in the field are needed. This paper presents an open-source, low-cost protection intelligent electronic device (IED) prototype for use in a laboratory environment. In particular, the IED design, its fastest measured performance, example results for different fault scenarios, and an assessment of its use in education are shown. The open-source IED is useful to accelerate industrial and academic research, as well as to enable education in protection for MTDC grids.
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| 9. |
- Jahn, Ilka, et al.
(författare)
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Functional Modelling of MMC Control and Protection
- 2023
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Konferensbidrag (refereegranskat)abstract
- The behavior of modular multilevel converters (MMCs) is, to a large degree, determined by their control and protection (C&P) software. Understanding and managing the functionalities of the C&P software are becoming relevant in high-voltage direct-current (HVDC) systems with setups ranging from electrical proximity of single-vendor systems, connections on the same AC or DC busbars to more advanced multi-vendor setups with split C&P software as done in China. Some concept-level ideas for clustering C&P software functions have been put forward. However, the organizational and management aspects have not been discussed in the available literature. This paper presents the model-based systems engineering (MBSE) methodology as a possible approach to organizing software functions and their implications and interactions in multi-vendor HVDC setups. Some practical aspects are illustrated using an example, and future developments and synergies with other tools are discussed. The presented ideas are meant to stimulate discussions in the field of multi-vendor HVDC interoperability - a domain that will have to manage complex software and hardware, such as to deliver the anticipated unprecedently high number of HVDC systems.
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| 10. |
- Jahn, Ilka, et al.
(författare)
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On the Partitioning of MMC Control Systems Using Graph Theory
- 2022
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Ingår i: IEEE Open Journal of Power Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 2644-1314. ; 3, s. 611-620
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Tidskriftsartikel (refereegranskat)abstract
- Control systems of modular multilevel converters can be partitioned into several levels. Such partitioning is becoming relevant in multi-vendor high-voltage direct-current systems where one party may deliver the converter hardware and associated control, whereas another party may deliver the system-related control. However, the exact control system partitioning has not been subject to research. This paper presents a method for partitioning control systems into two levels with minimum dependencies between the two levels. Furthermore, the impact of specific control designs on the partitioning and integration effort is discussed using an example. The presented method is useful for the design of multi-vendor control systems for modular multilevel converters whose partitioning otherwise would be based on engineering intuition
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| 11. |
- Jahn, Ilka, et al.
(författare)
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Requirements for open specifications in multivendor HVDC protection systems
- 2020
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Konferensbidrag (refereegranskat)abstract
- Integrating multiterminal high-voltage direct-current (HVDC) connections into the existing alternating current (AC) power transmission system is a possible solution for transport of large amounts of renewable energy. Protection is considered a key enabler for multiterminal HVDC (MTDC) grids. Designing such a protection system is a challenge, in particular in a multivendor setup. Fault detection during transients might be required to achieve the stringent speed requirements for HVDC protection. This in turn requires knowledge about the expected system behaviour during faults and involves knowledge from all vendors supplying equipment in MTDC grid. Traditionally, HVDC projects are, however, supplied as turn-key solutions and the control and protection systems are the intellectual property of the vendors and not open for the HVDC end-users. This paper aims to provide a starting point on the discussion which information has to be shared between vendorsand HVDC end-users when designing MTDC grid protection. Simulations results show that missing information about certain aspects can lead to a failure of the protection system. A discussion on organization of the available information is added. Open specifications of the used equipment are useful to design safe and reliable MTDC grid protection.
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| 12. |
- Jahn, Ilka, et al.
(författare)
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Testing of an HVDC IED Prototype Using Field Recordings
- 2021
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Ingår i: 2021 23rd European Conference on Power Electronics and Applications, EPE 2021 ECCE Europe. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Testing of protection intelligent electronic devices (IEDs) for high-voltage direct-current (HVDC) systems is usually constrained to simulated HVDC faults because systematic testing with faults on full-scale HVDC systems is not feasible. However, all simulations are subject to inaccuracies. In this paper, an HVDC IED prototype is tested with real fault recordings from an operational point-to-point HVDC link. Firstly, the successful response of the prototype HVDC IED to fault recordings from a real system is presented. Secondly, the behaviour of different protection algorithms and filters is analysed, leading to conclusions about the applicability in a real system. The results are useful because the gained knowledge is based on both a real prototype HVDC IED and a real fault recording, and not a simulation.
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| 13. |
- Jovcic, Dragan, et al.
(författare)
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HVDC grid rollout in the European context: current status and challenges of HVDC grid protection
- 2021
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Ingår i: CIGRE Science & Engineering. - : CIGRE 21. - 2426-1335. ; 20, s. 106-124
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Tidskriftsartikel (refereegranskat)abstract
- This article provides an up-to-date overview of technologies and explores key barriers on the path to implementing High Voltage DC (HVDC) grid protection in the European context. It brings together a wide range of stakeholders including key equipment manufacturers, grid operators, developers, testing laboratories, consultants, research institutes and academia to evaluate the readiness of HVDC grid protection technology and to present a broad range of challenges for deployment.The paper reports on the latest full-scale testing of 3 different DC Circuit Breaker (DCCB) technologies from different vendors at an independent laboratory, reaching a high technology readiness level (TRL). Hardware IEDs (intelligent electronic device) or protection relays for HVDC grids have been developed by academia and industry and are tested in a real-time hardware in the loop environment with grid operators utilizing different protection algorithms. The outstanding challenges, including interoperability, are presented.The overview of multiple HVDC grid protection algorithms which have now been demonstrated in a real-time environment on detailed industrial case studies, is given. It is shown that the functional performance at system and component level is confirmed and initial harmonisation work is discussed.The paper further presents the latest work on developing cost models for HVDC grid protection, and discusses theopportunities for cost reduction for various components.It is concluded that HVDC grid protection CAPEX isdominated by DCCB costs, but this also depends on theadopted protection strategy.Different grid operators present their views on HVDCgrid protection deployment challenges related to gridplanning and practical aspects of installations in offshore environment.The overview of DCCB models including real-time modelling and model verification is provided. The emerging research trends on HVDC grid protection and DCCB technologies are also discussed.
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| 14. |
- Norrga, Staffan, 1968-, et al.
(författare)
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DC Interconnection of Adjacent Point-to-Point HVDC Links as an Enabling Step towards Deployment of Multiterminal HVDC Systems
- 2022
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Ingår i: Proceedings CIGRE Session 2022. - : CIGRE.
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Konferensbidrag (refereegranskat)abstract
- A transition from point-to-point HVDC links to multiterminal systems can save much investment cost, since the number of converter stations can be reduced. In addition, security of supply is improved since power can be routed in alternative paths in case of a converter or cable fault. Grid losses and unavailability are reduced as power flows through fewer converters. Finally, using fewer converters also reduces the environmental and visual impact as well as the planning and permitting issues. The equipment required for implementing multiterminal HVDC networks is rapidly gaining technical maturity. Several feasible solutions for DC circuit breakers (DCCBs) exist and have been demonstrated. Standardisation and testing of the DCCBs has evolved greatly. Furthermore, the development of controland protection methods for multiterminal systems has taken great strides recently. Still, however, the actual deployment of multiterminal or meshed HVDC systems has been almost non-existent outside China. The main reason is that HVDC operators wanting to benefit from multiterminal HVDC systemsface a vicious circle: practical experience in multiterminal HVDC is lacking, but cannot be gained because of the risks associated with a deployment when there is insufficient experience. The question is, therefore, how the risks can be mitigated. This paper proposes to create a direct DC connection between two existing, or planned, point-to-point HVDC links which both terminate in the same location. A particular case, involving the two links the SouthWest Link in Sweden, and the Hansa Power Bridge, linking Sweden and Germany, is studied in detail. By the proposed methodology, multiterminal operation and protection aspects can be verified at full scale at minimum risk. In the unlikely event that multiterminal operation cannot be achieved it is always possible to operate the links as point-to-point, i.e., as initially intended. The paper investigates several aspects of the proposed DC connection. First, a technical analysis looks into the load-flow and protection aspects. Notably, the combined system differs from multiterminal systems studied in literature in that there are several converters at the middle node and that both point-to-point and multiterminal operation should be possible. Load flow is managed by a power and voltage droop control of the converter stations. For protection, DCCBs will be employed in the DC connection, to ensure unimpeded operation of one of the links in case of a fault on the other link. The study considers two different types of DCCBs: hybrid and mechanical. These differ in terms of cost and speed ofoperation. A multitude of simulations verifies the function of the protection scheme. Furthermore, a detailed cost-benefit analysis (CBA) looks into the economic aspects of the DCconnection. Apart from the CAPEX and the running cost, the CBA indicates the substantial saving resulting from avoiding converter losses for power routed directly between the end nodes. Moreover, an expected improvement in availability of the overall link is shown. Several scenarios with regard to the power flows are evaluated. In addition, the socioeconomic welfare gain and the redispatch savings are considered. The mentioned cost savings could make the DC connection profitable. Finally, the legal and regulatory aspects of the DC connection are also evaluated considering that eventhough the DC connection will be located on Swedish territory it would also influence socioeconomic welfare in Germany.
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| 15. |
- Wang, Mian, et al.
(författare)
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Multi-vendor interoperability tests of IEDs for HVDC grid protection
- 2020
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Konferensbidrag (refereegranskat)abstract
- Future large scale HVDC systems must have components from different manufacturers, however, this will require multi-vendor interoperability. This paper studies multi-vendor interoperability of HVDC protection IEDs using hardware IED prototypes developed by industrial and academic partners. Multi-vendor interoperability tests are performed using real-time hardware-in-the-loop simulations based on open-access converter models configured to represent the proposed three-terminal design of an extension to an existing point-to-point HVDC system in the UK. In particular, this paper focuses on developing testing procedures for IEDs in a multi-vendor environment and identifying possible interoperability issues. Interoperability of two hardware IEDs is demonstrated during primary protection, IED failure backup protection and breaker failure backup protection. In each case, the protection scheme operates correctly and it is shown that, in the studied scenarios,the protection IEDs are interoperable.
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