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.
Line-Commutated Converter (LCC) based HVDC lines are widely used to transmit electric power and interconnect asynchronous AC systems. Due to the characteristic of LCC-based HVDC, large amount of reactive power consumed by HVDC potentially deteriorates system voltage stability. Reactive power control is crucial to alleviate adverse impacts of HVDC reactive power consumption from AC network and secure...
Planning the expansion of distribution systems (DS) is a nonlinear and combinatorial problem that combines technical and regulatory constraints. Commonly, the planning of DS is intended to achieve a radial topology to reduce its complexity. However, in a smart-grid context, distribution feeders are subject to reconfigurations to transfer load between feeders in failure events, or to compensate for...
This study investigates the impacts of Plug-in Electric Vehicles (PEV) on end-service local distribution feeders. The results show that the PEV charging depresses the feeder voltages significantly and increase the feeder power losses up to 16.7 times. The voltage stress is more profound at the end of the feeder or at the point where many PEV are connected. The most noticeable impact of the PEV is...
There is a growing interest in utilizing demand-side flexibility to provide ancillary services. Various methods have been proposed for frequency control with thermostatically controlled loads, yet few consider practical load constraints. In this paper, we develop a fully decentralized method to provide primary frequency control (PFC) with domestic refrigerators taking into account startup compressor...
The objective of this paper is to present a real-time co-simulation platform for analyzing electric power grid operation, taking into account integrated communication systems. This paper discusses how a co-simulation platform can be set up using OPNET and OPAL-RT as communication and power system simulators, respectively. A simplified distribution automation case study is demonstrated to show how...
Given the relatively new context in which Distributed Geeneration (DG) is inserted in distribution systems, for certain aspects of the operation of this type of system there are relatively few studies of power quality considering the presence of DG. One of these aspects is certainly the possibility of DG operating under unbalanced three-phase operating conditions, which is quite common in distribution...
This paper proposes a new transmission-constrained unit commitment method that combines the cost-efficient but computationally demanding stochastic optimization and the expensive but tractable interval optimization techniques to manage uncertainty on the expected net load. The proposed hybrid unit commitment approach applies the stochastic formulation to the initial operating hours of the optimization...
An on-line line switching method based on a three-stage strategy to effectively relieve overloads in power systems is proposed. The proposed method is designed for on-line applications in the control center environment. To balance the requirements of solution speed and of effectiveness, the proposed three-stage method is composed of screening stage, ranking stage and detailed analysis stage. One distinguishing...
Substations play an important role in power systems. The application of the IEC61850 standard changes the situation of the traditional substation greatly. The information in the intelligent substation is rich, but it is difficult for the operators to digest them in a short time without an effective assistant tool. A fault diagnosis method which uses the alarming information of the primary and secondary...
This paper presents an average-value model of a line commutated converter-based HVDC system using dynamic phasors. The model represents the low-frequency dynamics of the converter and its ac and dc systems, and has lower computational requirements than a conventional electromagnetic transient (EMT) switching model. The developed dynamic-phasor model is verified against an EMT model of the CIGRE HVDC...
Mechanical failure is the main fault of transformer on-load tap-changers (OLTC), and part electrical failure, to a certain degree, is originally caused by mechanical malfunctions. In order to detect the hidden mechanical faults of OLTC timely and effectively, this paper presents the fuzzy C-Means (FCM) algorithm to recognize the distribution patterns of reconstructed vibration signals, which are closely...
Conventional centralized dispatch has inherent drawbacks to handle the increasing penetration of distributed generation in distribution systems. This paper discusses a decentralized synergetic dispatch paradigm for prosumer-based interconnected microgrids, in which a prosumer is defined as an autonomous agent that can produce, consume, and store electricity. We consider a double-sided market mechanism...
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...
Korea Electric Power Corporation (KEPCO) developed a Korean Smart Distribution Management System (K-SDMS) to address many issues of distribution system control, including the lack of receptivity of distributed generations (DGs). Voltage-VAR control (VVC) program is one of the K-SDMS real-time mode applications. VVC calculates the references of voltage and reactive power control equipment, which minimize...
This paper presents a model for a MV/LV bidirectional solid state transformer (SST) for distribution system studies. A multilevel converter configuration is used in the MV side for voltage and current harmonic reduction. The model has been implemented in the ATP version of the EMTP. Several case studies have been carried out in order to evaluate the behavior of the SST model under different operating...
This paper introduces a simple and fast heuristic approach for solving the distribution feeder reconfiguration problem with an objective of loss reduction and voltage profile improvement. In this paper, a single power flow solution is executed to specify all bus voltages and branch currents. The branch currents are utilized as switching indices to determine the open and closed status of sectionalized...
In this paper, the authors discuss a set of software laboratory assignments on power distribution systems that address emerging and smart grid technologies such as the interconnection of solar PV generation and of microgrids, of series compensation and capacitor placement and control, and selective meshed structure. Although these software laboratory modules can be used by any university and user,...
Given the emphasis on reliability of life-safety equipment in facilities, this paper will report the findings of an extended (Part 2) NEMA 5VS Section sponsored survey on electrical surge damage to such equipment and the financial impact for electrical systems and life-safety equipment. Further, the paper will outline the expected transient voltage surge environment in an electrical system with a...
Gas-insulated switchgears (GIS) are emerging as more capable power system assets than conventional air-insulated switchgears (AIS), especially in terms of operational reliability and maintenance requirements. However, insufficient consideration is often given to comparing GIS and AIS substation project options. Therefore, a more effective approach is needed to better inform project investment decisions...
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...
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.