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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...
This paper investigates an optimum control strategy for an isolated dual-active-bridge DC/DC converter based on MMC (Modular Multilevel Converter) technology. The control goal is to achieve minimal current magnitude for given power transfer and to provide fast control for full positive and negative power range. The control strategy is derived in the rotating dq frame. The optimal operation is achieved...
As photovoltaic (PV) integration increases in distribution systems, an effective way of assessing the maximum allowable PV integration capacity is urgently needed. In this paper, a new method is proposed to evaluate the maximum PV integration capacity with AC power flow limits, and the effect of topology reconfiguration on PV integration is also considered. In addition, the single commodity flow constraint...
Point-to-point VSC-HVDC Wind power plant (WPP) links connected offshore by AC cables can be called an AC integrated VSC-HVDC scheme or virtual multi-terminal DC (MTDC) grid. Since, the AC integrated VSC-HVDC scheme forms an offshore AC grid, parallel operation of offshore VSC-HVDC converters is required. This paper compares three offshore converter control topologies: (i) feedforward control of AC...
Performing co-simulation studies on transmission and distribution systems software environments requires linking the transmission system elements in the former with highly detailed distribution network models and probabilistic load models in the latter. This paper presents a two-step algorithm for: (i) creating a scalable distribution system in a bottom-up approach to match the connected load at the...
Three types of offshore wind power collection topologies are studied for DC power systems in this paper. Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) is considered and the Optimal Power Control (OPC) is used for the Maximum Power Point Track (MPPT) control. The failure of a wind power unit is regarded as the fault condition in this paper. Voltage control...
The development of algorithms for enhancing the resilience and efficiency of the power grid requires evaluation with topologies of real transmission networks. However, due to security reasons, such topologies and particularly the locations of the substations and lines are usually not publicly available. Therefore, we study the structural properties of the North American grids and present an algorithm...
This paper proposes a two-stage network processor for the supervisory control of multi-terminal HVDC grid that connects different AC areas. The proposed network processor processes the DC substation topology locally in the first stage and analyzes the HVDC grid connectivity at the supervisory controller. The processor uses the k-means clustering method to detect the islands in HVDC grid and prepares...
This paper proposes an event-driven approach for reconfiguring distribution systems automatically. Specifically, an optimal synchrophasor sensor placement (OSSP) is used to reduce the number of synchrophasor sensors while keeping the whole system observable. Then, a wavelet-based event detection and location approach is used to detect and locate the event, which performs as a trigger for network reconfiguration...
The Modular Multilevel Converter (MMC) topology is discussed intensively as a crucial part of future DC grids, especially to integrate offshore wind power. While generalized voltage source converter models are usually utilized for multiterminal investigations, conclusions on transient DC grid behavior and on ACDC interactions during distorted AC grid conditions are hard to draw or limited in their...
Most existing approaches for distribution network reconfiguration assume that the distribution system is (three-phase) balanced and a single-phase equivalent is used. However, distribution feeders are usually unbalanced due to a large number of single-phase loads, nonsymmetrical conductor spacing, and three-phase line topology. This paper builds on our previous work and studies feeder reconfiguration...
The growing integration of distributed energy resources (DERs) in urban areas raises various reliability issues. To ensure robust distribution grid operation, grid monitoring tools are needed, where the topology reconstruction serves as the first step. However, the topology reconstruction is hard in distribution grid. This is because 1) the branches are difficult and expensive to monitor since most...
This paper presents a comprehensive two-step topology and frequency scan tool (TFST) developed by ERCOT to assess the potential subsynchronous resonance (SSR) vulnerability associated with the series compensations in the meshed transmission networks and various generation resources, including synchronous generators and inverter technology based generators. In the first step, the topology scan applies...
The focus of this paper is to develop a framework to evaluate and analyze the reliability of the power electronic circuits in electric vehicle chargers, which are expected to be a major component of the utility load in the future. A general infrastructure of electric vehicle charging systems is described and different charging levels are discussed. To illustrate a numerical reliability analysis, two...
This paper presents a deterministic optimization technique for the optimal location of normally open switch on a real distribution network, located in north of Portugal. The goal is to find the optimal radial topology that minimizes the power losses. The method is developed in TOMLAB software, and is formulated as a mixed integer quadratic programming problem. Given the current characteristics of...
This paper proposes an algorithm for determining the optimal composition which means number of links and section switches in a feeder and placement of automatic switches in a Distribution Automation System (DAS). A DAS is configured by automatic switches and reclosers on a power distribution line. The composition and placement of switches affect the operational applications of a DAS. More switches...
The modular multilevel converter (MMC) has become an attractive option for dc/ac conversion in many power system applications, in particular for HVDC transmission. Due to its parallel arrangement of phase legs the MMC is known to be a wye configured architecture. In this paper, the equivalent delta formulation of the conventional wye architecture is introduced. The delta configured MMC, enabled by...
As the power distribution grid moves towards actualizing the concept of a smart grid, the dependence of reliable and secure grid operation on the communication architecture and data is increasing rapidly, along with the possible cyber-attack surface. In this paper first an agreement algorithm for a distribution substation with radial topology is presented that leverages the communication capabilities...
This paper proposes the concept of PV_VSG, which mainly means combining Photovoltaic (PV) and Virtual Synchronous Generator (VSG) together. To control PV_VSG operating well in stand-alone mode, a novel control strategy is proposed to match the PV output and the load, which can prevent the PV output voltage from collapsing. First, the topology and the operation scenarios are investigated. Then, the...
A three-phase ac-ac matrix converter for inductive power transfer (IPT) systems with soft-switching operation and bidirectional power flow is introduced. The proposed converter can generate high-frequency current directly from a three-phase ac power source without a dc link. Unlike conventional ac-dc-ac converters, the proposed converter can provide a high frequency current without any current sag...
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