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Thyristor converters are used as power conditioning systems for superconducting coils. The objective of this work is to discuss the series compensation of thyristor converters using variable series capacitors. Traditional thyristor converters can control the coil voltage by changing the firing angle and then also the lagging power factor on the ac side. Similarly, the series capacitor can control...
Converters using active switches can improve harmonic components of input current and power factor. Moreover, these converters contribute to the footprint downsizing. However, increase of switching losses and EMI due to high frequency switching is one challenge of these types of converters. This paper proposes a new active rectifier circuit topology, which can reduce the switching losses and EMI with...
This work attempts to explain reactive power consumption in a line commutated HVDC transmission system and suggests a possible solution to reduce it. A series injection strategy has been formulated using voltage-source converters and the effects have been simulated indicating a significant reduction in reactive power consumption by the converter terminal and consequently that supplied by the source...
A real-time model of a current controlled plug-in electric vehicle (PEV) parking lot (SmartPark) has been presented in this paper. The controller of the SmartPark is designed in such a way that the active and reactive power transaction with the grid can be controlled independently. Also, the controller limits the current going out of the vehicle during grid faults for batter protection. The realtime...
This paper presented a grid-connected inverter incorporating multiple technical concepts like “single-stage”, “multilevel” and “transformerless”, and thus attracting in cost and efficiency. Also energy storage (ES) was integrated to assist extensive power regulation. A complete control scheme was developed to achieve wide range real/reactive power management involving pure real power, pure reactive...
This paper proposes a new starting method of a harmonic current compensator using a hybrid active filter for wind power generation systems. In the proposed method, an active filter of the hybrid power filter behaves a resistor and reactive power compensator to suppress the inrush current and leading currents for the passive filter under the starting condition. The basic principle of the proposed starting...
Multilevel converters and inverters have become the enabling power conversion technology for high voltage high power applications in today's power systems and large motor drives. Although the neutral-point clamped (NPC, a 3-level) inverter was invented in 1979, the multilevel concept was not formally established until the early 1990s when the diode-clamped multilevel inverter, the capacitor-clamped...
Grid code requirements on wind power plant are becoming more stringent as the wind power penetration level increasing. In order to identify the risk of incompliance with grid code requirements at the planning stage of a wind power plant project, a standard grid code study process has been established in Vestas. The study process includes steady state load flow, short circuit studies and transient...
This paper investigates how different approaches to grid synchronization and reference frame orientation can improve the control performance of a voltage source inverter operating in a weak grid. It is first shown how voltage-sensor-less operation based on Virtual Flux allows for flexibility in how to choose the reference frame orientation of the control system. The different possible orientations...
In this paper, a model-based controller is proposed for Hybrid HVDC transmission systems. Hybrid HVDC comprises a Line-commutated Converter (LCC) and a Voltage Source Converter (VSC) which are connected on the same DC link. The VSC regulates the active and reactive power using a model-based controller in a synchronous reference frame while the LCC maintains the DC voltage using a proportional and...
This paper proposes a new islanding detection method for use in a small-scale, grid-interconnected distributed generator system. The proposed islanding detection method is based on voltage fluctuation injection, which can be obtained through high-impedance load switching on the grid periodically. The correlation factor between the periodic switching signal and the perturbed voltage is then used as...
In the Tokaido Shinkansen, SVCs (static var compensators) have been installed at the single-phase feeder side in select substations to reduce the descent in the feeding voltage. A single-phase STATCOM (static synchronous compensator), called an RPC (railway static power conditioner), consists of a back-to-back converter whose AC terminals are connected to the two power systems of a Scott transformer...
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