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.
Stability-constrained optimal power flow (SOPF) is an effective and economic tool to enhance stability performance by adjusting initial steady-state operating conditions, with the consideration of rotor angle and short-term voltage performance criteria. SOPF belongs to the category of dynamic optimization problems which are computationally expensive. In order to reduce its computational complexity,...
This paper studies the feasibility of utilizing the reactive power of grid-connected variable-speed wind generators to enhance the steady-state voltage stability margin of the system. Allowing wind generators to work at maximum reactive power limit may cause the system to operate near the steady-state stability limit, which is undesirable. This necessitates proper coordination of reactive power output...
The paper investigates the applicability of averaged-value models (AVM) for modular multilevel converters (MMC) operating in a voltage sourced converter based high voltage dc (VSC-HVDC) grid. The AVM models are benchmarked by comparison with a detailed electromagnetic transient (EMT) model of the grid including a full-detail MMC model. Analysis results show that the AVM is only effective as long as...
Due to the uneven geographical distribution between load and wind power, currently it is difficult to integrate the large-scale wind power into the State Grid in China. There are significant wind curtailments for wind farms due to system restrictions. This paper proposes a new way of utilizing wind power, i.e. in-situ consumption, as an alternative to the costly development of long-distance transmission...
Demand response (DR) has proved to be an inevitable part of the future grid. Much research works have been reported in the literature on the benefits and implementation of DR. However, little works have been reported on the impacts of DR on dynamic performance of power systems, specifically on the load frequency control (LFC) problem. This paper makes an attempt to fill this gap by introducing a DR...
This paper presents a direct power control strategy for a doubly fed induction generator by using an artificial neural network controller with the multilayer perceptron structure. This controller generates the direct- and quadrature-axis rotor voltage signals from both the stator current and voltage that are measured by the Hall sensors. The input variables of the control system are the rotor speed,...
This paper presents a method for the identification of winding failures in induction motors. The types of failures include unbalanced currents flowing into the motor and short-circuit of the winding. The radiated magnetic field of a typical induction motor was studied while various types of failures applied to the machine. The implementation was performed by applying different types of unbalanced...
This paper presents a hierarchical demand response (DR) bidding framework in the day-ahead energy markets which integrates customer DR preferences and characteristics in the ISO's market clearing process. In the proposed framework, load aggregators submit aggregated DR offers to the ISO which would centrally optimize final decisions on aggregators' DR contributions in wholesale markets. The hourly...
We propose a stochastic generation expansion model, where we represent the long-term uncertainty in the availability and variability in the weekly wind pattern with multiple scenarios. Scenario reduction is conducted to select a representative set of scenarios for the long-term wind power uncertainty. We assume that the short-term wind forecast error induces an additional amount of operating reserves...
A new internal fault protection scheme for synchronous generators, based on Fuzzy inference system, is proposed. The proposed method is developed and tested by using oscillogram dataset gathered from fault simulations and experiments conducted on real-life synchronous generators. Data-mining is used to support the choice of the most relevant variables to identify synchronous generator internal faults...
In this paper, a novel solution method is proposed for the optimal topology control problem in AC framework with N-1 reliability. The resultant new topology of the proposed method is guaranteed to yield a better objective function value than the global solution of the problem with the original topology. In order to prove our statement, semi-definite programming relaxation is formulated to find a lower...
This paper proposes a new model reduction algorithm for power systems based on an extension of balanced truncation. The algorithm is applicable to power systems which are divided into a study area which requires a high-fidelity model and an external area, making up most of the power system, which is to be reduced. The division of the power system can be made arbitrarily and does not rely on the identification...
A hierarchical decentralized network reconfiguration approach to minimize power losses for smart distribution systems is presented in Part I. In this paper, the proposed approach is applied to four test distribution systems to examine its performance. A demonstration system consisting of the test system and distributed intelligent agents is built using Matlab/Simulink to illustrate how the decentralized...
This paper presents a quantitative method to determine delay requirements of the information and communication technology (ICT) system supporting wide-area power oscillation damping (WAPOD) controllers. An allowable time delay for the ICT infrastructure named “equivalent time delay (ETD)” is defined. The ETD is calculated by numerically comparing the damping behavior of the system when local input...
The task of autonomous power sharing in a micro-grid is usually achieved by decentralized droop control on individual interface power converters, which may suffer from the dependence on output line impedances. Inaccurate reactive power sharing will occur under strongly non-uniform line impedances. Due to inherently distributed and heterogeneous nature of the micro-grid, it becomes an ideal platform...
This paper aims to study the measurement and modeling methods for delays in wide-area closed-loop control systems (WACS). The delays are classified into communication delays and operational delays based on the information flow of WACS. For communication delays, an affine evaluation model is proposed based on previous studies, and this model is verified by the measured communication delays of the Guizhou...
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...
The objective of this paper is to propose a human expert-based approach to electrical peak demand management. The proposed approach helps to allocate demand curtailments (MW) among distribution substations (DS) or feeders in an electric utility service area based on requirements of the central load dispatch center. Demand curtailment allocation is quantified by taking into account demand response...
This paper introduces a DC transmission grid with fault tolerant inductor-capacitor-inductor (LCL) voltage source converters (VSCs) and using slow protection system based on mechanical DC circuit breakers (CBs). LCL VSC inherently regulates DC fault current to levels that converter can sustain for prolonged periods which avoids IGBT tripping and brings significant advantage in security and reliability...
A novel model predictive control (MPC) scheme is developed for mitigating the effects of severe line-overload disturbances in electrical power systems. A piece-wise linear convex approximation of line losses is employed to model the effect of transmission line power flow on conductor temperatures. Control is achieved through a receding-horizon model predictive control (MPC) strategy which alleviates...
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.