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This paper proposes a grid code for photovoltaic (PV) integration to mitigate overvoltage and voltage variation problems caused by a large amount of PV generation in distribution circuits. According to the simulation results, PV generation causes overvoltage and voltage variation problems in distribution circuits. To mitigate the overvoltage and voltage variation problems due to the high penetration...
In recent years, the voltage quality in rural areas has aroused strong concern from the Stat Grid Corporation of China. This paper firstly analyze the over-voltage issues in the rural distribution networks from HUNAN province, and then proposes an output voltage control scheme of the Electric Spring (ES) to alleviate severe over-voltage problem in rural areas. The control objective of the ES is to...
The objective of this research is to analyze and evaluate the performance of the proposed shunt-series switched multi-functional grid-connected inverter (SSS-MFGCI) for mitigating unbalanced voltage sag and swell problem in distributed generation system or microgrid. Three quantitative performance evaluation factors, namely fault level factor, rating factor, and grid stiffness factor, are proposed...
This work proposes and investigates a renewable energy distributed generation system involving a matrix converter with an output filter working as a stable voltage supply. This is especially relevant for the stand-alone operation of a renewable energy microgrid where a stable sinusoidal voltage with prescribed amplitude and frequency under various load conditions is the main control objective. A controllable...
Droop control is a widely used technique for load sharing in DC microgrids (MGs). However, it has its limitations due to the MG voltage deviating from its rated level and, more importantly, it suffers from possible poor current sharing accuracy. Voltage drops across coupling line impedances is the main factor that causes these limitations, which is further deteriorated by the virtual impedance introduced...
With rapid increase of photovoltaic (PV) penetration in distribution system, and the fact that distributed generators may involve in voltage regulation according to IEEE standard 1547, it is necessary to check the stability of PV generator integration, especially utility PV farms. To apply generalized Nyquist Criteria (GNC) based on impedances on D-Q frame, output impedances of PV farm is derived...
DC (Direct Current) microgrid has gained more attention caused by the development of distributed generations and DC loads. The control objectives for DC microgrid are voltage regulation and current sharing. In order to achieve these objectives, consensus based control methods with communication have been extensively studied recently. It is a common strategy to modify the voltage set point of local...
In this paper, a power system model is proposed to achieve a decentralized voltage control scheme. A stabilizing controller design is presented to solve the voltage regulation problem with output feedback. The model is intended to be an exact representation of frequency and terminal voltage, which will allow us to cope with time-varying parameter uncertainties, and also unknown design parameters of...
Recently the Smart Transformer (ST) has been discussed as a replacements for the traditional transformer, driven by its advantages in terms of controllability and renewable energy integration. Although the Smart Transformer has lower efficiency than the conventional transformer, its control functionality has the potential to be used for wider system energy savings. This paper proposes a control, namely...
The focus of this paper presents a distributed control method based on the gossip communication mechanism that will regulate the voltage of active loads in islanded microgrids. The proposed distributed voltage control (DVC) strategy based on the gossip protocols is fully distributed and by the way of the discrete-time communication; moreover, each active load unit only requires the local voltage and...
As adoption of electric vehicles increases exponentially globally, there is a need for continuous relevant research in the area of the impacts of charging infrastructure integration on the grid. One of such impacts is voltage regulation. This paper develops a practical time-varying electric vehicle load model as opposed to the state-of-the-art static constant load model and simulates the impact of...
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...
This paper presents a new approach for generation source management in a dc microgrid, which uses a hybrid isochronous-droop (HID) control strategy to overcome the inherent drawbacks of traditional droop control and achieve a performance more towards that which can be achieved by communication-based distributed or centralized control schemes. In particular, the approach allows the number of dc sources...
Due to the insignificant share of inverter-based Renewable Energy Resources (RER) as well as the uncertainty concerning their integration impacts, the capability of RERs to regulate voltage or frequency has not been widely used. However, inverter-based voltage/frequency regulation is of interest due to the fast growth of distributed RERs, especially solar Photovoltaic (PV) resources. The IEEE 1547a...
Microgrid (MG) consists of distributed generation (DG) units, which supply MG loads via the power network. Droop-based control system has been proposed for power sharing implementation among DG units in MGs. The droop control performance is based on the power network variables, which makes it easy to implement. As the control system at the primary level, the droop controller plays a major role in...
The active residential DC distribution feeder operation under integration of distributed solar photovoltaic generations (DSPVG) is expecting poor voltage profiles due to increasing demand of SPVG and load. This paper discusses, the dynamic droop based coordinated controlled voltage regulation approach to address the rise/drop of voltage in an active DC power distribution system (DCPDS). Modern DCPDSs...
As negative incremental resistance caused by constant power behavior of power converters may bring stability problem to distributed systems, stability of PV integration to distributed system attracts more and more attention. Compared to the widely used positive impedance method, D-Q Frame impedance matrix method is more accurate for integration of PV generator that has non-symmetrical control in DQ...
In this paper, a H∞ robust controller is designed for high-gain boost converter (HGBC) using mixed-sensitivity method. This controller design is based on the model, which uses a linear time-invariant approximation of nonlinear time-variant PWM converter that describes approximately the behavior of the system. The design of voltage-mode controller for boost converter is challenging, as its duty cycle...
Thanks to incentive policies for the development of solar generation technologies, the world has recorded such an expensive generation technology largely deployed in daily life. It is expected a similar prospect to battery energy storage system (BESS) which is a multi-benefit solution with high penetration of renewable energy in general and solar rooftops in particular. In low voltage networks with...
Power Quality within LV distribution and Smart Grid systems is an important issue. Open Unified Power Quality Conditioner (Open UPQC) is a possible solution to improve power quality level within distribution smart grid networks. This paper presents the ICT-based power control in order to manage cooperation between series and shunt units of Open UPQC. The cooperation is meant to improve system functionality...
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