A general mathematical model for LVRT capability assessment of DER-penetrated distribution networks

Low voltage ride through (LVRT) is one of the indispensable issues of recent decade in the context of grid codes. LVRT stands for the ability of a generation facility to stay connected during the voltage dip. Despite the numerous discussions in recent works, but they mostly concentrate on the LVRT-based control of distributed energy resources (DERs) integrated into a microgrid and its improvement. However, what has been hidden and not addressed any more yet is an index to measure the LVRT capability of a DER-penetrated distribution network (DPDN) under different voltage sags. This takes precedence when we want to evaluate the LVRT capability of DPDNs with consideration of various LVRT categories of DERs mandated in IEEE 1547 standard. This paper introduces a general framework for LVRT assessment of a DPDN by solving a system of differential algebraic equations (DAEs). Then expected LVRT capability of a DPDN is evaluated by a proposed LVRT index through the implementation of Monte Carlo simulation technique.This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/fi=vertaisarvioitu|en=peerReviewed

An Analytical Framework for Evaluating the Impact of Distribution-Level LVRT Response on Transmission System Security

Low voltage ride through (LVRT) is a solution to increase the tolerance of distributed energy resources (DERs) against the voltage sags. However, the possibility of DERs trip according to the present grid codes exists. Such trips are essential for transmission systems with connected DER-penetrated distribution networks (DPDNs). This paper investigates an analytical framework to see the impact of distribution-level LVRT response on transmission system security. LVRT response stands for the total amount of lost DER capacity due to the inability to meet the LVRT requirement during the voltage sag. This generation loss in the distribution sector can expose the transmission network to lines overloading after fault clearance. The proposed novel approach is based on a source contingency analysis that lets TSOs conduct an LVRT-oriented security assessment. A mathematical function is defined as the LVRT response function of DPDNs. This function gives the lost DER capacity in response to the transmission level transient faults and is constructed by distribution system operators (DSOs). The TSO can use these functions to assess the loading security of transmission lines in post-clearance conditions. In this analytical framework, LVRT-oriented security is evaluated by calculating the risk of lines overloading under a large number of random faults.The proposed approach is implemented in two test power systems with a considerable DER penetration level to obtain the risk of line overloading due to the LVRT response in distribution networks.©2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed

Peak-Load Management of Distribution Network Using Conservation Voltage Reduction and Dynamic Thermal Rating

The peak-load management of a distribution network (DN) has gained attention by increasing the electric power consumption on the demand side. By developing smart-grid infrastructures, effective utilization of the DN’s components and proper management of the DN would create a valuable solution for DN operators. Hence, in this paper, a peak-load management framework is proposed in which the real-time rating of the components and voltage-dependent features of the electric loads help the DN operator handle the peak times successfully. In addition to the individual advantages of efficient operation of the DN, more practical results are obtained by combining the conservation voltage reduction (CVR) and dynamic thermal rating (DTR) of the DN’s lines and transformers. Based on the obtained results, compared to the individual implementation of CVR, the cost-saving level is increased significantly during the peak events using the simultaneous utilization of DTR and CVR. Furthermore, a discussion is presented about the current problems of the feeders supplying the voltage-dependent constant-power loads during CVR utilization, which is resolved by the dynamic rating of the DN’s components

Peak-Load Management of Distribution Network Using Conservation Voltage Reduction and Dynamic Thermal Rating

The peak-load management of a distribution network (DN) has gained attention by increasing the electric power consumption on the demand side. By developing smart-grid infrastructures, effective utilization of the DN’s components and proper management of the DN would create a valuable solution for DN operators. Hence, in this paper, a peak-load management framework is proposed in which the real-time rating of the components and voltage-dependent features of the electric loads help the DN operator handle the peak times successfully. In addition to the individual advantages of efficient operation of the DN, more practical results are obtained by combining the conservation voltage reduction (CVR) and dynamic thermal rating (DTR) of the DN’s lines and transformers. Based on the obtained results, compared to the individual implementation of CVR, the cost-saving level is increased significantly during the peak events using the simultaneous utilization of DTR and CVR. Furthermore, a discussion is presented about the current problems of the feeders supplying the voltage-dependent constant-power loads during CVR utilization, which is resolved by the dynamic rating of the DN’s components