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This paper deals with the interruption scheme designed using Vacuum Circuit Breaker (VCB) based on zero crossing characteristics, implemented electromechanically for High Voltage Direct Current (HVDC) system. The operation is carried out using Mechanical scheme as it has minimum energy loss in comparison to Solid-State and Hybrid schemes. The Mechanical scheme consists of series connection of multiple...
In this paper, an asymmetric mixed MMC topology of multilevel converter for bipolar HVDC transmission systems is introduced. Among the existing MMC topologies for the bipolar HVDC systems, the asymmetric mixed MMC topology provides the benefits of: a lower number of submodule cells, fewer switching devices and lower conduction losses. Furthermore, the HVDC based on asymmetric mixed MMC can be flexibly...
Modular multilevel converter (MMC) has been proved a prospective topology in high voltage and high power occasions. Hybrid MMC mixed with half-bridge (HB) and full-bridge submodules (FBSMs), which achieves a good tradeoff between power devices quantity and dc short circuit fault handling capability, attracts extensive attention. In this paper, the characteristics of SM capacitor voltage ripples are...
Half-bridge (HB) modular multi-level converter (MMC) based bipolar HVDC transmission systems can be employed to transfer bulk power over long distances with high reliability and flexibility. However, this configuration exhibits special fault behaviors that should be taken into account during its design stage. For instance, a single-phase-to-ground fault at the valve-side of the HB-MMCs will lead to...
Hybrid modular multi-level converter (Hybrid MMC) topology, consisting of both half-bridge (HB) and full-bridge (FB) submodules, is suitable for HVDC application as it combines the advantages of both HB-MMC and FB-MMC. This paper focuses on the control aspects of hybrid MMC with the objective of limiting DC fault current. It is also controlled to exchange reactive power with the AC grid during DC...
Research on direct current (dc) interruption has grown in recent years, driven by increased interest in using high voltage direct current (HVDC) for large power transmission and future grids. In fact, dc interruption poses particular challenges to protection devices and circuit breakers and new technologies are needed to meet the requirements of future HVDC grids. In this paper we review some of the...
Modular multi-level converters (MMC) are considered a promising topology for HV applications Uke HVDC transmission systems. Such systems must be designed to provide high reliability against different types of faults. MMCs using Half-Bridge (HF) cells are well known for lacking the capability to block short circuits in the DC link. On the contrary, Full-Bridge (FB) cells can block the short circuit...
In recent years, significant progress has been made in HVDC transmission by the advent of voltage-source-converter (VSC) technology using modular multilevel converters. There is increasing demand to interconnect the existing HVDC lines into meshed HVDC grids for better renewable energy penetration. In this paper, a series of power electronic topologies, all based on the front-to-front VSC structure,...
The Modular Multilevel Converter (MMC) and Alternate Arm Modular Multilevel Converter are the emerging converter topologies which are most effective and suitable for HVDC systems. The AAMMC represents a hybrid multilevel converter topology with high capability for high voltage applications. One of the serious problems of the HVDC system is the blocking of DC side faults. The MMC can be used to limit...
High Voltage Direct Current technology has certain characteristics which make it especially attractive for transmission system applications. HVDC transmission system is useful for long-distance transmission, bulk power delivery and long submarine cable crossings and asynchronous interconnections. The study of faults is essential for reasonable protection design because the faults will induce a significant...
Ferroresonance is a non-linear resonance which can typically occur when a saturable magnetizing inductance forms a resonance circuit with a capacitor. An example of such a resonance condition can be a system configuration where an overhead transmission line with series compensation terminates into a HVDC converter transformer. Such a configuration may lead to post fault ferroresonance oscillations...
HVDC interruption technique is the bottleneck problem of flexible HVDC project. The HVDC vacuum circuit breaker based on artificial current zero is a feasible and effective method to solve this problem. In this circuit breaker, the parameters of the commutation branch have a vital influence for the breaking process. In this paper, the interruption process for HVDC based on artificial current zero...
Transmission of power over long distances has become an important aspect in today's world because of offshore generations from wind, ocean currents, tidal, waves and others. In general, HVDC technology is well-accepted around the world. The VSC-HVDC has gained importance over the years. Certain problems regarding protection still remain, but with the implementation of the hybrid breaker, the system...
The Modular Multilevel Converter (MMC) is a promising technology for medium-high voltage DC/AC converters, being adequate for HVDC transmission systems. Among the appealing characteristics of the MMC are their modularity, and consequently their scalability, as well as the fact that there is no bulk storage element. One key aspect for the operation of the MMC is the response in the event of a short...
Self-blocking MMC (SB MMC) is able to isolate DC fault current and is promising for use in overhead HVDC transmission. Each converter arm of a SB MMC is consisted of half the self-blocking sub-module (SBSM) and half the half bridge (HB) sub-module. This hybrid design achieves the DC fault isolation capability without significantly increase of the cost and power loss. The detailed electro-magnetic...
This paper presents an optimal design of the modular multilevel converter (MMC) based LCL DC/DC converter suitable for high voltage direct current (HVDC) systems. The design aims in minimizing the converter total power losses, harmonic pollution, volume and weight. The optimal values for the converter main parameters affecting the above objectives including cell capacitance, operating frequency, and...
The modular multilevel converters are vulnerable to DC side faults, which are severe that can destruct the system if it is not designed to withstand these kinds of faults. This paper presents an analysis of the HVDC modular multilevel converter (MMC) based on full-bridge submodules during DC side fault conditions. A detailed theoretical analysis of the behavior of the full-bridge MMC during fault...
This paper analyzes the possible range of the DC currents developed by a pole-to-pole DC fault in a Modular Multilevel Converter (MMC) -based high voltage direct current (HVDC) system, using half-bridge submodules (SM), when the actual control and protection (C&P) scheme for the system recently installed in China is applied. The results derived from differential equations are validated by hardware-in-the-loop...
In the HVDC grid hybrid circuit breakers are adopting stack of solid state SW (S/S) has the capability to break the fault current. The S/S of the circuit breaker comprise several semiconductors which are connected in series. The importance of large capacity of S/S has been shaping up in the HVDC circuit breaker. However, the rated capacity of power semiconductor at S/S is not enough to overcome the...
This paper describes a control approach that allows the cell capacitors of the full-bridge modular multilevel converter (FB-MMC) to be controlled independent of dc link voltage. Also the control approach offers the possibility of operating the FB-MMC from bi-polar dc link voltages; thus, creating new possibilities for building generic hybrid dc grids with reversible dc link voltage, where conventional...
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