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With the expansion and enhancement of the power transmission network, short-circuit current (SCC) has become a major concern in grid operations. While transmission switching is one effective solution to reduce the SCC without investing in additional equipment, switching lines could threaten system N-1 security. To find an efficient, and secure, yet economic switching solution, this paper proposes...
In this paper, the prestrike and the restrike effects during switching a vacuum circuit breaker (VCB) connected to a dry-type foil-winding transformer are theoretically and experimentally analyzed. The analysis is conducted by performing a wide range of experimental three-phase switching ON/OFF tests for a 3.75-MVA prototype test transformer connected to a VCB by a cable with different lengths and...
We propose a model of a battery switching station (BSS) for electric buses (EBs) that captures the predictability of bus operation. We schedule battery charging in the BSS so that every EB arrives to find a battery ready for switching. We develop an efficient algorithm to compute an optimal schedule. It uses dual decomposition to decouple the charging decisions at different charging boxes so that...
This paper proposes a self-healing strategy for two neighboring islanded microgrids (MGs) that are connected together through a normally open interconnecting static switch (ISS). Each MG is expected to support the other during power deficiencies, which is facilitated by the developed self-healing agent. This agent operates based on either a centralized approach, when data communication system is available,...
This paper presents the disturbance rejection of peak current-mode control for bidirectional Buck-Boost converter using slope compensation. The equivalent circuits and transfer functions are derived for the peak-current mode control using small signal modeling. In order to utilize the benefits of peak current-mode controller and eliminate its drawbacks, slope compensation has been added. The derived...
Battery storage systems (BSSs) have been used to participate in day-ahead scheduling of active distribution network (ADN). BSSs play significant roles in improving the efficiency of distributed generations (DG) utilization and economy of ADN operation. In this paper, a new optimal charging/discharging scheme of BSSs is proposed in ADN with DGs. Both time-of-use (TOU) price and the price difference...
Based on the dynamic time warping (DTW) matching method, a novel appliance identification algorithm for low frequency sampling load data is proposed. First, residential load sequences are segmented into subsequences composed of single appliance load profiles and multi-appliance load profiles. Then, reference load sequences of all candidate appliances, which have identical lengths, are generated before...
In recent years, voltage and reactive power control in distribution systems is becoming increasingly complex with the growing penetration levels of distributed energy resources (DER), electric vehicle loads, and new requirements like conservation voltage reduction (CVR). Traditional approaches of voltage control rely on slow acting electromechanical devices installed on the primary feeder. These approaches...
The unified power flow controller (UPFC) is one of the most advanced devices in the flexible AC transmission system (FACTS) family. The modular multilevel converter (MMC) has recently become popular in high voltage direct current (HVDC) transmission and FACTS systems. The application of the MMC in a UPFC is an innovative idea, but its controller features a complex and hierarchical structure that requires...
Determination of the optimum number and placement of sectionalizing switches in Distribution Automation (DA) feeders is a very challenging task. This is an important step in the feasibility process of DA projects and one has to consider the trade-off between reliability and economics to arrive at the answer. This paper presents a novel iterative approach based on the relative reduction in the normalized...
In order to improve the economic benefit of AC / DC hybrid microgrid, an optimal operation under spot price method is proposed. Firstly, an expectation programming model is constructed considering the spot price as the control variable; Secondly, based on day-ahead dispatch, considering the WT and PV power forecasting error, an real-time adjustment strategy is presented, which considers the real-time...
This paper presents an efficient method to introduce renewable energy to an extreme and area lack of water resource and power supply. This paper systemically explains the process to install dispersed sources in a small-scaled rural power system. Three accurate calculation methods are selected and used for estimation and prediction of local power load including industrial park. The simulation defined...
With the increasing penetration of renewable energy, sudden changes of renewable generation output and unbalance generation among areas introduce new challenges for frequency regulation. This paper aims to provide an attempt to coordinate multiple groups of aggregated air-conditionings for providing supplementary primary frequency regulation service. Based on the thermal modelling of air-conditioning,...
This paper observes the boundary of distribution system security region (DSSR). DSSR is defined as a set of all the operating points satisfying N-1 security constraints. First, the basic concepts of N-1 security are introduced for distribution system under smart grid background. Then, the dividing phenomenon of operating points security is reported, which indicates that DSSR boundary of a given distribution...
The wide application of distributed generations (DGs) and microgrids (MGs) infuses new vitality into the voltage control of the inverter, which represents a traditional power electronic research area. In this paper, a self-synchronized resonance voltage control algorithm is proposed to satisfy the requirement of an inverter's seamless switching from grid-connected (GC) mode to stand-alone (SA) mode,...
In order to fully take advantage of the available reactive power from EV chargers (EVCs), a volt-var optimal control (VVOC) strategy for power system integrated with wind farms is proposed. The VVOC strategy consists of two steps: day-ahead optimal scheduling and intra-day optimal adjustment. In the first step, on-load tap changers (OLTCs) and capacitor banks (CBs) are scheduled to minimize the power...
The smart grid is a typical cyber-physical system (CPS) utilizing more advanced information and communication technologies (ICTs), in which hierarchical control system (HCS) plays an essential role. However, it should be noted that for the same control function, HCSs could have multiple modes for making control decisions. They may have different cyber structures and information flows, which could...
The paper develops a mathematical model for a modular multilevel converter (MMC) using extended-frequency dynamic phasors. The developed model is capable of capturing both the low- and high-frequency dynamic behavior of the converter depending on the requirements of the study to be performed. The paper shows the mathematical development of the model, its validation against a fully detailed electromagnetic...
This paper presents a smart service restoration method for electric power systems. Power system restoration (PSR) is the procedure of restoring the power supply after a power outage. Its objective is to restore the power system rapidly while satisfying all the operation constraints. Although it has been studied and applied most only to electrical distribution systems. The proposed methodology takes...
This paper investigates DC network partition and alternative DC fault protection strategy for Multi-terminal HVDC (MTDC) system. Fast acting DC Circuit Breakers (DCCBs) or fault blocking DC-DC converters can be configured at strategic locations to allow the entire MTDC system to be operated interconnected but partitioned into islanded DC network zones following faults. In case of any DC fault event,...
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