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.
Operational planning of a small and isolated energy system having a large wind farm and a battery storage device is studied. Operational planning decisions are to be made in two time-scales: daily unit commitment (UC) and hourly dispatch. For this problem, Markov decision process (MDP) and stochastic programming (SP) are combined to account for both daily and hourly changes of wind uncertainty. Two...
This paper proposes a Quasi-Monte Carlo (QMC) simulation based multi-objective economic dispatch, which aims to reduce the fuel cost and emission of the grid simultaneously. During the simulation, QMC models the stochastic behaviours of wind speed and distributed loads with low-discrepancy sequences. In comparison with conventional Monte Carlo (MC) simulation, the computational complexity of QMC is...
While renewable generation sources provide many economic and environmental benefits for the operation of power systems, their inherent stochastic nature introduces challenges from the perspective of reliability. Existing optimal power flow (OPF) methods must therefore be extended to consider forecast errors to mitigate in an economic manner the uncertainty that renewable generation introduces. This...
The inclusion and modeling of uncertainty in conventional load flow is required with the enhancement in the penetration of intermittent generation. As a result, the multi-modality is there in output distribution functions. In this paper, a probabilistic load flow method is used with two wind generator models with multimodal loadings and a spline based reconstruction technique is introduced for the...
The work presented in this paper addresses the problem of main grid dependability in micro grids using Electric springs. The micro grids which have more penetration of renewable sources are bound to depend on main grids during generation intermittence of the micro sources. In order to reduce the dependability of micro grids on main grid an efficient energy management algorithm has been presented....
Power system operation became a challenging with the integration of variable and uncertain Renewable Energy Sources (RES) generation. The operational flexibility describes the technical ability of the power system to respond to the net-load within a controllable power at a certain time to accommodate the RES power output. The main objective of this paper is to analyse and evaluate the impact of the...
Deregulated electricity markets consist of look-ahead and real-time markets, across which energy price is generally volatile. Moreover, dispatch and pricing decisions in the real-time market strongly hinge on the quality of the real-time state estimation routines, which are designed to provide real-time information about operation state of the grid. The adversaries can leverage price volatility in...
The timing and the locational values of operating reserves (ORs) need to be rewarded to improve reserve deliverability and adequate incentive for flexible generating resources in a transmission network. An enhanced deterministic unit commitment model incorporated with hourly updated zonal operating reserve demand curves (Z-ORDCs) is proposed in this paper. Reserve zones are defined by the approach...
Uncertainties in frequency regulations (FR) of generators and loads, and their effects on probabilistic power flow (PPF) analysis are addressed in this paper. The conventional PPF analysis is based on power flow model, without considering the frequency regulation. However, according to frequency regulation characteristics, generation outputs and load demand will respond to frequency deviation. Furthermore,...
The goal of this paper is to present a design of a voltage controller via state-feedback control. An efficient power system model to measure voltage and frequency is introduced. The model including uncertainties is admitted to be time-dependent, with a priori known upper and lower bounds. A method to solve the stabilization problem of the power system model subject to uncertain time-dependent parameters,...
Power system voltage stability is a crucial aspect of power system study, and loads have a significant influence on it. This paper uses PV curves to rank the power system loads according to their influence on the voltage stability. The Monte Carlo simulation is used to generate uncertainties to reflect the stochastic behaviour of power systems. The ranking order is acquired after considering different...
This paper describes how to calibrate key parameters (eye amplitude, eye height and eye width) of eye pattern generators using an oscilloscope which is directly traceable to basic physical quantities. Various correction methods are applied to reduce measurement uncertainties, which are estimated by use of the covariance matrix method.
We show that the existing variants of marginal participation approach may not be truly efficient in cost-allocation. In some approaches cost-causality is compromised, while in the other approaches, economic slack bus selection is not fair. This could lead to aberrations like price volatility, negative nodal prices, price signals that do not promote usage of lightly loaded sub-networks (and vice-versa),...
Utilizing of the power system stabilizer (PSS) is a common approach to eliminate the low frequency power swings. The phase lag that must be compensated by the PSS to increase the damping of the system efficiently should be carefully obtained from the excitation system; but, the uncertainty in the excitation system data is an unavoidable issue and must be eliminated. This paper utilizes a comparative...
Accurate sizing of power reserve (PR) due to inaccurate forecast of both renewable energy sources (RES) and load demand in a microgrid can provide substantial cost reductions. This paper proposes two strategies to dispatch the PR into different power generators. The first one uses only micro gas turbine (MGT). The second one uses MGTs plus PV based active generators (AGs). The latter enables the RES...
Robust Unit Commitment (UC) model has been intensively investigated as an effective approach to hedge against randomness and risks. All existing robust UC formulations consider uncertainties in demand and/or cost. We observe that, nevertheless, a power system could be seriously affected by surrounding temperature and there is a strong relationship among the efficiency of gas generators, demand and...
Structural analysis provides methods to find all possible residual generators in an over-constrained model structure. The number of residual candidates though growths exponentially with the degree of over-constrainedness. Since on the one hand not all candidates are necessary for fault detection and isolation and on the other hand not all candidates provide sufficient information to distinguish between...
Aggregations of controllable loads are considered to be a fast-responding, cost-efficient, and environmental-friendly candidate for power system ancillary services. Unlike conventional service providers, the potential capacity from the aggregation is highly affected by factors like ambient conditions and load usage patterns. Previous work modeled aggregations of controllable loads (such as air conditioners)...
Power system operators have traditionally addressed system uncertainty through the scheduling of operating reserves. These reserves are excess capacity, either online or offline, that can quickly be used to address unforeseen events in the load profile. As renewable energy resources, namely wind and solar, new techniques are being developed to address the uncertainty introduced from these sources...
The use of expert knowledge is always more or less afflicted with uncertainties for many reasons: Expert knowledge may be imprecise, imperfect, or erroneous, for instance. If we ask several experts to label data (e.g., to assign class labels to given data objects, i.e. samples), we often state that these experts make different, sometimes conflicting statements. The problem of labeling data for classification...
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.