The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper attempts to thoroughly evaluate the long-term performance of the most well-established voltage control strategies applied in active medium-voltage (MV) networks. This is attained by performing an exhaustive probabilistic analysis to consider and assess the impact of generation and demand uncertainties on the network operation. More specifically, Monte Carlo-based time-series simulations...
The mathematical model of the power system load node is proposed. The main elements of the model are synchronous and asynchronous motors, a power transformer, power transmission lines and capacitor banks. The voltage instability of the electrical grid and the starting transients of the asynchronous motors are considered in the proposed model, in contrast to the counterparts. On the basis of this model...
Many state of the art voltage control algorithms aim at reducing voltage rise in distribution grids caused by distributed in-feed, e.g. Photovoltaics (PV), by reactive power control strategies or active power curtailment. Due to the R/X-ratio, the effectiveness of reactive power on the voltage is generally more effective in medium voltage networks (MV) compared to low voltage networks (LV). For small...
The integration of uncontrolled distributed generation (DG), like photovoltaic and wind turbines, and the growing amount of connected loads in the medium voltage (MV) grids have worsened the voltage variability, and in extreme cases violating the voltage limits. New mechanism and control action for supporting the voltage must be adopted, due to the unpredictability of these resources. The power electronics-based...
This paper investigates the impact of the Fault Ride-Through (FRT) capability and the dynamic reactive power support of large-scale PhotoVoltaic (PV) systems according to the newly proposed German Grid Code (GGC) on short-term voltage stability. The PV system is based on a generic model and realistic parameters are used that are determined in consultation with a manufacturer. In this context, improvements...
Reactive power control by loads is one of the methods to control voltage in distribution lines. The authors improved reactive power control method by use of power factor correction converters which are often used in loads. The method modifies input current reference by multiplying sawtooth wave and controls reactive power by changing slope of sawtooth wave. It was confirmed that the method can control...
There has been a significant rise in photovoltaic (PV) system installations throughout the last decade. This has posed some technical challenges to the distribution grid operators. Unfamiliar impacts of these relatively new energy sources now should be handled more comprehensively. The rigidity of these impacts mostly depends on PV penetration level, grid and weather characteristics as well as the...
Due to the significantly increasing of Photovoltaic generations in distribution system, many utilities have reported about the adversely impact of high penetration PV on voltage variations. The various reactive power control strategies have been proposed to solve this issue. The aim of this paper is to study the performance of the implementation of three reactive power control strategies i.e. cosφ,...
Adoption of Battery Energy Storage Systems (BESSs) for provision of grid services is increasing. This paper investigates the applications of BESS for the grid upgrade deferral and voltage support of Medium Voltage (MV) distribution systems. A BESS is modelled in Matlab/Simulink to perform peak load shaving and voltage support service from the perspective of Distribution System Operators (DSOs). An...
Local reactive power control of distributed generators (DG) can be used to mitigate the voltage rise effect caused by themselves. In this paper, dynamic interactions between local voltage controllers of the DG units and transformer on load tap changers (OLTCs) are studied using time domain simulations. Studies are conducted with different control modes of DG unit and OLTC control and also secondary...
One of the main issues related to the optimization of the MV (middle voltage) network is to reduce losses of active and reactive power. Lower losses of active and reactive power give not only economic advantage, but also improvement of energy quality. The object of regulation that can be used for these purposes are transformer with On-Load Tap Changer and capacitor's banks. This paper presents results...
This paper is aimed to model the electrical transmission grid of Germany accessing future of electricity generation targeting year 2023. For the need of alternating current, while shutting down nuclear power plants and reduction of emission of green house gases, renewable energy comes into picture. With the data from German Network Regulatory Body (BNA), the high voltage transmission grid of Germany...
This paper proposes an individual-phase reactive power control strategy for an active load balancer (ALB) in three-phase four-wire distribution systems. The authors offer the simplest method to control different amounts of individual-phase reactive power for each phase on three-phase four-wire distribution feeders. The basic principle of the proposed power factor adjustable reactive power control...
This paper presents modeling and analysis of the potential benefits of joint actions of a MV/LV three-phase power distribution transformer with independent on-load tap-changer control on each phase and photovoltaic inverters provided with reactive power control capability, in terms of accommodating more renewable generations in the LV grid. The potential benefits are investigated in terms of voltage...
The impact of the increasing connection of distributed generation to medium voltage (MV) distribution feeders, with particular reference to photovoltaic (PV) units, justifies the application of an adaptive control of voltages and reactive power flows. This paper describes the analysis of a voltage/var control (VVC) structure that includes the cooperative control of the reactive power regulators of...
In this study, we investigate two countermeasures using inverters of photovoltaic (PV) power generation systems to avoid short-term voltage instability caused by sudden shutoff of the PV systems after a voltage sag. One of the countermeasures is the operation of the PV system at a leading power factor in the normal state, and the other is the dynamic reactive power control after the fault. First,...
Constant power factor control of a power conditioning system in a large-scale photovoltaic generation system (PV system), such as a mega-solar system, is introduced to mitigate voltage variations on a distribution line. However, it is difficult for the control to mitigate the voltage variation on a long distribution line because of the loss on the distribution line. This paper proposes an advanced...
In an effort to better understand the impacts of high penetrations of photovoltaic (PV) generators on distribution systems, Arizona Public Service and its partners completed a multi-year project to develop the tools and knowledge base needed to safely and reliably integrate high penetrations of utility- and residential-scale PV. Building upon the APS Community Power Project-Flagstaff Pilot, this project...
Based upon the analysis of the mechanism of power loss and voltage drop in distribution system, a new automatic control method of reactive compensation, namely, Feeder Power Factor Assessment (FPFA) is proposed in this paper. Promising that the voltage of all nodes is qualified, the proposed method aims at keeping the power factor of feeders between 0.98 and 1.0 in lagging, so that the reactive power...
Because of the increasing share of renewable energies violations of the statuary voltage limits occur more and more often in the German distribution grids. Therefore, distribution system operators take advantage of reactive power support by dispersed generation units for voltage regulation. Commonly, only one standard cosφ(P)-profile is implemented as a control-method for all units to decrease voltage...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.