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With the development of offshore wind power generation, large-capacity medium-voltage wind turbine becomes the development trend. In this paper, the cascaded multi-cell topology with four-quadrant operation capacity is applied to medium-voltage wind power converters, which consist of a large number of switching devices, so it is essential to improve the converter's fault-tolerant ability. Once the...
This paper proposes a new high-voltage Pulse Generator (PG), fed from low voltage dc supply Vs. This input supply voltage is utilized to charge two arms of N series-connected modular multilevel converter sub-module capacitors sequentially through a resistive-inductive branch, such that each arm is charged to NVS. With a step-up nano-crystalline transformer of n turns ratio, the proposed PG is able...
Integrated power systems (IPSs) with medium voltage direct current (MVDC) distribution are gaining importance in civil and defense marine vessels as they promise to provide cleaner, more reliable operation of vessels along with reduced fuel consumption. The integration of battery energy storage systems (BESSs) in the MVDC distribution system enables peak shaving of generators, optimal scheduling of...
This paper deals with fault tolerant control of a sinusoidal EMF five-phase permanent-magnet synchronous generator (PMSG) connected to an AC-DC converter without neutral connection. Under one open phase condition, the proposed global method is based on an original approach optimization problem minimizing copper losses and cancelling torque ripples. The used optimization algorithm is based to a Particle...
Vacuum as switching medium has been established widely in the distribution systems for more than 30 years. Well known for its outstanding and reliable interrupting capability of fault and load currents of all possible nature, the vacuum switching technology is now dominating the medium voltage level up to 52 kV. Technical advancements in the field of vacuum physics in last decades made it possible...
This Paper carried out three phase and single phase short circuit tests and verified the security and stability of large scale wind farms integration on Rongcheng power station. Including location and type of short circuit, system operation conditions and measurement of date, summarized the main work between the wind farms short circuit test. Following the ideas of “unit level-wire level-wind farm...
With the rising demand for electrical energy in an aircraft and the increase in operating voltages of the electrical distribution networks, the probability of occurrence of an arc fault is also increased. New protection devices such as arc fault detectors are now integrated in the network to break the circuit in case of an arcing event. To determine the optimum location of these protection devices,...
Evaluation of relay misoperations provides an opportunity to improve the design of backup protection schemes. Existing generator station backup protection schemes use distance protection (21) or voltage controlled/restrained overcurrent protection (51V) elements for clearing phase faults that are not cleared by either line protection or generator protection. Many schemes also use transformer ground...
Recognizing that line-to-ground (L-G) faults are the most likely type of faults to occur, many industrial power systems are equipped with resistance grounded neutrals (NGR) to limit L-G fault currents. Limiting, identification and isolation of L-G fault currents prevents the progression of L-G faults into multiple phase faults with large fault currents and considerable damage to power systems. Under...
Offshore platforms have critical and isolated electrical power supply system including large direct-online motors connected to the generation bus. This paper discusses complications involved in applying protection systems including generator and generator-transformer differentials in coordination with motor starting and motor protection for such applications. Recommendations are provided for applying...
Conventional distribution networks are mostly radial and are fed by central sources located at the transmission level. The power flow direction in these networks is unilaterally from sources to load feeders. In recent years, to meet the growth of demand, there has been an upward trend in the integration of distributed generation (DG) units to distribution networks. Although, the connection of DG units...
This paper examines the combination of two very usual phenomena occurring in an emerging power system, such as the Provincial Interconnected System (PIS) in San Juan-Argentina. The first of these phenomena is known as fault induced delayed voltage recovery (FIDVR). This article discusses some aspects of the influence of induction motors on voltage sags. Another phenomenon analyzed is the increasing...
The aim of this work is to evaluate the impact of the incorporation of dynamic voltage support and reactive power injection requirements in PV systems connected at Provincial Interconnected System(PIS) of San Juan-Argentina projected up to the year 2024 under different levels of penetration. To this aim, the calculation of a severity indexes is proposed. It can be concluded that the capacity to withstand...
The electrification of heat and transport along with significant increases in distributed energy resources pose challenges for distribution network operators (DNOs) as they evolve into distribution system operators (DSOs). Issues may include capacity constraints, voltage excursions, lower supply security and reduced power quality. A method of addressing these matters whilst unlocking capacity is therefore...
Rotor winding interturn short circuit is the main fault of synchronous electric machines, it is of great significance to the safe and stable operation of the machine to discover and handle the fault timely. In view of this, the fault positioning method of rotor turn-to-turn short circuit of synchronous machines was studied. The mathematic expression of exciting magnetomotive force (e-m.m.f.), electromotiveforce...
The paper presents a method of the series arc fault for DC systems. The aim of the study is to find some current characteristics, which can be significant for the purpose of arc detection. The validity of the proposed method is testified by analyzing the arc fault current signal. The low voltage series DC arc study is carried out on the currents waveforms acquired during some tests on electric appliances...
Several technical power system architectures are being evaluated for the Navy's next generation all-electric warship. One concept being considered includes a scheme to power both port and starboard busses from a single generator with dual-windings. This approach offers redundancy and reduces the effects of prime mover light loading, but it inherently couples the two busses through the common generator...
In terms of power supplies and power conversion, power electronics based converters have their own advantages. Proper condition monitoring for power electronic converter has become necessary which is now in incipient stage. This paper includes different kinds of failure modes associated with power electronics at the converter as well as device level and recent Condition Monitoring (CM) techniques...
This paper presents a novel protection technique for the detection of inter-turn faults in synchronous machines. It is based on the calculation of voltage in the stator windings from the usual phases and neutral voltage, typically available in all generator protection relays. The existing turn-to-turn protection mechanisms require additional voltage transformers. The main contribution of this technique...
In view of the appearance of parallel stator winding open circuit fault in large capacity permanent magnet wind turbines, the negative sequent current is caused in stator windings, which may endanger the stability of the wind turbine. With the 2-D transient electromagnetic field, the negative sequence current with the rated condition and fault condition is calculated. Further more, the change rule...
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