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In this paper, a new structure and the coordinated control method of a delta connected static var compensator (SVC) based hybrid active power filter (SVC-HAPF) for reactive current, harmonic current and unbalanced current compensation are proposed. The proposed delta-connected SVC-HAPF has the desirable characteristics of wide compensation range with low voltage/current rating requirement in the active...
Cascaded H-bridge converters based islanded microgrids are applied to integrate the distributed generators (DGs). The accurate load sharing is an important task for the research of microgrids. Due to the characteristics of series connection, all DGs share a single common current. In this paper, the power factor of each DG is assigned to be consistent via regulating both the frequency and voltage....
Considering the new challenges in the energetic scenario around the world, this paper proposes the implementation of a micro-grid with photovoltaic generation and local accumulation, considering its capability to operate connected or islanded from the utility grid. The system will supply power to utility grid and local loads through six single-phase inverters in wye configuration, three of them operating...
Modular multilevel converter (MMC) is one of the recent developed converter for high power applications. However, the major drawback of this converter in variable speed drives is that the capacitor ripple voltage increases at lower speed, when the load torque remains constant. This ripple voltage can be reduced by reducing the dc-bus voltage at lower speeds, while the capacitor voltages are maintained...
In this paper, a novel configuration of the back-to-back (BTB) converter interconnecting two synchronous AC grids is proposed. The feature of this BTB converter configuration is the substantially reduced capacity compared with the exchanged power between the two grid partitions. Unlike the conventional full-capacity BTB converters, the capacity of the proposed BTB converter in this paper is around...
In this work, three-phase single stage grid-connected photovoltaic system using current control inverter is simulated using Matlab/Simulink. To deal with varying irradiance conditions, the incremental conductance MPPT has been used, however in order to improve the power quality a three-level (NPC) inverter based SVM control together with LCL filter has been used. The main result of the project is...
Metro is integral to the urban rail transit with the expansion of the city. Due to the tremendous power consuming of the traction load which is generally considered to be megawatt-class, the attendant problems concerning energy-saving and emission-reduction cannot be neglected. An approach wherein the photovoltaic plants are connected into the metro traction power supply system to provide electrical...
This paper proposed an adaptive impedance control method in multi-bus distributed islanded micrigrid to share reactive power accurately and suppress circulating current. The multi-bus distributed microgrid is more complicated than one-bus because of its different bus voltages and variable structure. To deal with the power sharing problem in multi-bus distributed islanded micrigrid, two methods have...
With the increasing capacity of grid-connected PV power grids, photovoltaic power generation systems that are connected to the utility grid have shown increasing competitiveness. When the voltage drop occurs due to power short circuit fault, a Low Voltage Ride Through(LVRT) Technology is proposed to improve the stability of the power system. This work, based on the research of PV grid-connected inverter...
Although the wireless power transfer (WPT) has been used in a wide range of areas, there are many difficulties with the development of WPT. The load voltage quality problem caused by the high susceptibility of the delivered power to the surrounding is still a key issue to be solved. To guarantee a high quality of dc load voltage in WPT system, this paper proposes a novel voltage control strategy based...
Input-series-output-series (ISOS) inverter system is very suitable for high input voltage and high output voltage power conversion applications. If the inverter system topology is applied to the grid-connected application, a large-capacity inverter system can be built with multiple small-capacity standardized inverter modules, which will improve system reliability and simplify system design. For the...
This document describes a predictive controller specifically designed to trade-off DC bus voltage regulation error, reactive power compensation and active power curtailment during abnormal operating conditions. The controller proposed evaluates different curtailment alternatives during grid faults and applies the optimal control action that enhances the system performance.
Installation and control of proposed and/or connected distributed generation is constrained technically by the relevant protection systems, network structure and by documentation that governs its operation. This documentation which refers openly to the regulatory framework, standards and specification both by a utility, municipality or government regulatory body guides the manner in which a distributed...
This paper proposes a novel reactive power control strategy based on virtual flux droop method. Firstly, flux droop control method is derived, where comlicated multiple feedback loops and parameter regulation are avoided. Next, the factors influencing reactive power sharing are theoretically analysed in virtual flux control. Then, a novel reactive power droop controller is designed which consists...
Continuous voltage compensator was developed to improve power quality issues of distribution lines. It consists of series and shunt transformer connected through static power converters. In this paper, the compensation methods using series and shunt converters were investigated, and manufacturing of actual rating 6.6kV 3MVA prototype was reported.
The total real power injected by distributed renewable energy sources (RES) in the low voltage (LV) grids can cause voltage rise effects during light load scenarios. Integrating RES in microgrid architectures can result in improved power quality of the electrical grid, by avoiding the voltage rise effect from occurring and also by providing ancillary services to the grid. In this paper, a cascaded...
The paper deals with the current progressive balancing from the target of constant p or constant q component of instantaneous power to symmetrical current target. Referenced current imbalance depends on the operation mode and whether the current reaches the limit. The fixed p component of power is selected for the inverter operation mode. The fixed q component of power is selected for the rectifier...
Conservation Voltage Reduction (CVR) schemes and renewable energy based distributed generation (DG) can be coordinated to maintain lower node voltages for reducing load consumption and line losses in distribution systems. In addition, smart inverter interfaced DGs are significant resources to maintain the lowest possible voltages at the loading points and adjacent nodes. This paper describes a method...
With increased penetration of renewable energy sources in the bulk electricity system, it is important for power system planners and operators to maintain grid stability and carry out system impact studies for identifying reliability-related problems. Adequate models have been developed by the industry to represent positive sequence response of solar PV plants for grid interconnection studies. In...
According to the European grid code, grid-connecting converters should always be connected to the grid under grid voltage unbalance. However, grid voltage unbalance severely affects the stable operation of the converters and leads to the various power issues, such as active power oscillation, DC-link voltage ripple, and overloading. Moreover, under grid voltage unbalance, the active power delivery...
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