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This paper deals with circuit breakers (CBs) used in direct current microgrids (DCMGs) for protection against electrical faults, focusing on their evolution and future challenges in low voltage (<1.5 kV) and medium voltage (between 1.5 kV and 20 kV). In recent years, proposals for new circuit-breaker features have grown. Therefore, a review on the...
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As the developed version of solid-state circuit breaker, Z-source circuit breakers are providing an attractive research interest as a protection system in DC. Based on the typical Z-source circuit breaker, many topologies have been proposed in recent studies to reduce the breaker size or to demonstrate the breaker performance in different voltage c...
Citations
... In recent years, with the rapid development of renewable energy technology and the requirements for long-distance transmission, DC transmission technology, which is based on high-power electronics with low losses, has gained broad prospects in transport and distribution of electric power. Hybrid DC circuit breakers (DCCBs) with fast fault current cut-off functions play an important role in the DC systems as the foundation for the operation, control, and protection of DC networks [1][2][3][4]. ...
... MATLAB/Simulink was used to build this model [19]. The schematic diagram of the dynamic simulation model for the hybrid DCCB is shown in Figure 1, the construction of which is based on the topology of a diode full-bridge circuit [1,13]. The simulation model mainly consists of three branches connected in parallel, namely, a main branch with a fast mechanical switch (FMS) and an auxiliary sub-module (ASM), a transfer branch mainly composed of a submodule (SM), and an energy-absorption branch mainly consisting of a connected metal oxide varistor (MOV). ...
The state of the energy-absorption branch MOV in the hybrid DC circuit breaker (DCCB) has a very important impact on the short fault breaking operation of the circuit breaker. Therefore, it is necessary to evaluate the state of the MOV, which is also called the “sleep component”. Due to DCCB being placed indoors, the aging is mainly caused by short-circuit impulse current. Therefore, this paper mainly focuses on the study of the short-circuit impulse aging characteristics of the energy-absorption branch MOV. The dynamic simulation system of a hybrid DCCB was built to investigate the impulse of short-circuit current on the MOV of the energy-absorption branch during the circuit breaking process. Then, an accelerated impulse aging test platform was built and the accelerated impulse aging tests of the MOV were conducted. The aging characteristics of the MOV were analyzed in detail and detailed analysis was conducted of the macroscopic parameters and microstructure changes. The results indicate that the nonlinear coefficient α could be emphasized as a basis for judging the “sleeping” component states and aging degree of the hybrid DC circuit breaker, and can be expected to be applicable to MOV condition monitoring of BCCB in the future.
... As indicated in Section III, the window length is N = 12 with sampling frequency of 10 kHz and the threshold is 2.2 considering the most critical case. Operational time of the SSCB-type fault isolating device is considered around 600 μs, as defined in [50]. Communication links are not needed because the scheme requires only current of one side of the VSC line. ...
... As an alternative to silicon-based semiconductors, the use of WBG semiconductors brings great advantages in terms of volume and response time. WBG semiconductors also attain superior performance metrics when compared to silicon peers in terms of power density, switching frequency, and losses [107]. WBG materials are framed in the third generation of power semiconductors and include materials like silicon carbide (SiC) and gallium nitride (GaN). ...
Direct Current (DC) power system protection presents a major challenge due to its unique characteristics, namely the absence of natural zero current crossing points. Thanks to their features, DC protection devices allow the safe commutation of the fault current. Selective protection and fast fault isolation are key features that any Direct Current Circuit Breaker (DCCB) should feature, assuring minimal power outages and the effective protection of sensitive electronic components. To overcome the liabilities of mechanical circuit breakers (MCBs) and solid-state circuit breakers (SSCBs), several novel concepts of hybrid circuit breakers (HCBs) have been proposed over the years, to take advantage of the benefits of both the MCBs and SSCBs. This paper presents an up-to-date state of the art on the technologies applied to DC HCBs and describes novel HCB concepts. Design considerations, challenges and future trends are also discussed.
... As indicated in Section III, the window length is N = 12 with sampling frequency of 10 kHz and the threshold is 2.2 considering the most critical case. Operational time of the SSCB-type fault isolating device is considered around 600 μs, as defined in [50]. Communication links are not needed because the scheme requires only current of one side of the VSC line. ...
The paper proposes a fast fault detection method for
radial DC microgrids established on mathematical morphology
(MM) denoising filters and detection principles utilizing only local
measurements. The proposed fault detection algorithm utilizes
the DC fault current signal from a Voltage Source Converter
(VSC) and detects a fault. Problems related to communication
delays are thus avoided, while preserving the low cost and
computational burden.
The proposed fault detection framework includes five different
MM-based denoising filters, employed as pre-signal processing
methods whose features are assessed and compared. The influence of selecting an appropriate type and length of a structuring element (SE) on the proposed method is analyzed. The developed fault detection method based on MM is used for extracting transient features and detecting pole-to-pole (PP) and pole to-ground (PG) faults within milliseconds of their occurrence.
The proposed method is demonstrated using simulation tests
in MATLAB/Simulink. The results indicate that the proposed
method enables reliable, accurate and fast detection of both the
PP and the PG faults. Computer simulations are carried out
to verify that the proposed method distinguishes faults from
overload.
... Studies on existing DC power distribution systems, such as LV DC microgrids, provide guidelines for the protection coordination of DC common bus stations. In [57], a protection strategy is presented for a LV DC microgrid considering the coordination between different protective devices. In [58], a protection scheme ...
The paper deals with mathematical modelling and the control system for UltraFast Charging Stations (UFCS) based on DC micro-grid concept and Energy Storage System Integration to feed new Electrical Vehicles (EVs) at 800V DC in order to reach the EVs power requirement for charge-time less than 10 min. The UFCS integrates a battery energy storage system (BESS) to reduce the peak power of AC main grid, decoupling the dynamics of the DC charging station from the AC grid by means of its dedicated control system. Designing procedure and Control Strategy, based on Load Levelling power management, are dealt with numerical simulation results in Matlab-Simulink software, presented in order to verify UFCS performance and the charging station’s dynamics.
Developments in and around renewable energy and the advantages offered by DC over AC system have encouraged the usage of DC power technologies in transmission and distribution networks. However, DC infrastructure finds numerous challenges especially with switchgear and protection due to the non-existence of zero crossing, high rate of change of current during abnormal events, etc. To tackle the issues related to switchgear and protection, robust and fast response DC circuit breakers (DCCB) are required. This paper provides a systematic technical review of different types of DCCB and meta-analysis with respect to the advancement in technologies as per the market requirements. This technical review paper on DCCBs includes: (i) the working principles of different types, (ii) state of art, (iii) application in different areas, and (iv) assessment on the market scenario. Further, this paper also provides an insight on the future directions in research for the development of DCCBs emerging applications of DC system.
