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.
The voltage surge due to fast switching insulated gate bipolar transistor (IGBT) and resonance can introduce voltage surge and distort the inverter output voltage/current waveforms. This may cause premature failure to sensitive loads and introduce harmonics in the grid voltage/current waveforms. This paper investigates the impacts of voltage surge and resonance on power electronic converter-fed grid-connected...
A study was performed to determine the impact of single-phase photovoltaic (PV) generation on distribution laterals at high penetration levels. The study addresses concerns about the impact on load balance, fault current balance, power quality and islanding conditions. Methods and tools used for this study, which are appropriate for general analysis of PV on single-phase laterals, are discussed. Guidelines...
In the near future, transmission grids will include an increasing share of directly connected voltage source converters. These systems should be able to support the utility grid autonomously. The present paper reviews the most popular approaches to address the challenge of proper load sharing amongst multiple parallel inverters applied to the utility grid case. Originally developed for Microgrid or...
Currently, the standards used to calculate the short circuit (SC) current ignore the contribution of DC systems to the SC current when short-circuit faults occur in an AC systems. With the rapid development of High Voltage Direct Current systems (HVDC), it has become important to determine whether the contribution of the HVDC system can be ignored when calculating the SC current. This study investigates...
Solar is the fastest growing source of renewable electricity in the U.S. The anticipated PV proliferation brings integration challenges on system volt/var performance at the utility scale. One of the greatest challenges is to maintain desirable feeder voltages in utility distribution networks. The intermittent PV generation causes more frequent operation of volt/var control (VVC) devices to alleviate...
Rooftop Solar Photovoltaic (PV) systems installations have been increasing in the Low voltage distribution networks due to decreased cost and government incentives (e.g. feed-in-tariff). The high penetration of these PV systems can inject harmonics into the network causing problems to sensitive loads and controllers of loads. Due to the solar irradiation dependency, the power generation is variable...
New winding configurations for mutually coupled salient pole switched reluctance machines (MCSRMs) have been proposed that enables the application of three-phase standard inverters for variable speed drives. The proposed topologies comprise phase windings carrying balanced three phase currents from standard inverters along with DC excitation coils in the stator slots. Both concentrated and distributed...
The traveling wave protection performance of traditional DC transmission line can be influenced by fault conditions, so this paper proposes a traveling wave based directional pilot protection method. Analysis shows, for an internal DC line fault, that the forward traveling wave is less than the backward traveling wave at two ends of the proposed line within a short time of post-fault; but in the case...
The circuit parameters involving stray load loss and harmonic torques of high speed induction motors fed by inverters are determined by both finite element method and experiments, respectively. In the finite element method, the parameters are directly determined from the electromagnetic field distribution of the motors under load conditions. On the other hand, in the experiment, the parameters are...
Using the characteristic difference of transient energy, a transient energy based directional unit protection is proposed. Assuming the positive direction of current is from DC busbar to DC line, for an internal line fault, the detected transient energies on both ends of the line are all negative, which denote the positive direction fault. When an external fault occurs, the transient energy on one...
Proportionate sharing of load changes in a microgrid without communication among the generators is a difficult problem. In this paper an exact power sharing algorithm is developed that uses an optimization-based technique to minimize the exchange of state information among the generators. To demonstrate the application of the developed framework we present simulation results for a system constructed...
Line-commutated thyristor-controlled rectifiers are extensively used in industrial applications, where controllable dc voltage is required. The simulation software developments trend is towards proposing new packages for power electronics components that are computationally more efficient and still accurate. One of the most widely-used modeling techniques is known as parametric average value modeling...
In this paper, an I–V tracer which operates autonomously, with no need to be disconnected from its load, will be discussed. The current state of I–V tracers commercially available will be discussed and motivation will be provided for the online autonomous I–V tracer. Design of such an I–V tracer using the single-ended primary inductance converter (SEPIC) will be discussed, and simulation results of...
This paper presents an online clustering modeling method for large-scale photovoltaic (PV) power plants. The proposed method utilizes the defined feature distance of inverter control parameters as the clustering index to derive the equivalent PV plant model. Based on the offline parameter database and the online matching method, the feature distance weighted by online parameter sensitivity is obtained...
This paper presents a battery-based storage (BBS) for wind generator (WG) system. The BBS is composed by an Asymmetric Cascaded H-Bridge Multilevel Inverter (ACMI) with staircase modulation. The proposed structure is connected in parallel to the whole WG system. Such connection plus the use of the ACMI allow a reduction in the power losses, compared to the commonly found storages connected where the...
Reactive power compensation is used by utilities to ensure customer voltages are within pre-defined tolerances and reduce system resistive losses. While much attention has been paid to model-based control algorithms for reactive power support and Volt Var Optimization (VVO), these strategies typically require relatively large communications capabilities and accurate models. In this work, a non-model-based...
Decentralized methods for computing optimal real and reactive power setpoints for residential photovoltaic (PV) inverters are developed in this paper. It is known that conventional PV inverter controllers, which are designed to extract maximum power at unity power factor, cannot address secondary performance objectives such as voltage regulation and network loss minimization. Optimal power flow techniques...
This paper proposes a new strategy to achieve voltage regulation in distributed power systems in the presence of solar energy sources and battery storage systems. The goal is to find the minimum size of battery storage and its corresponding location in the network based on the size and place of the integrated solar generation. The proposed method formulates the problem by employing the network impedance...
Recent trends of rising demands of electricity for supporting critical infrastructure have led to increasing interest in microgrids. Microgrids hold the promise of being the reliable and economically viable electric system which can greatly improve the efficiency, resiliency and eco-friendliness of future smart grid. Recently, several techniques have been proposed to managing microgrids. In this paper,...
Islanding condition happens when a DG units continues to energize a part of the grid while that part has been isolated from the main electrical utility. In this situation if the DGs power exceed the load then Transient Over Voltages (TOVs) occurs. Because of the adverse effects of the islanding and TOVs, power system sections must detect, mitigate the over voltage, and disconnect the DG systems from...
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.