A Two-layer Framework for Mitigating the Con-gestion of Urban Power Grids Based on Flexible Topology with Dynamic Thermal Rating

The urban power grid(UPG)combines transmission and distribution networks.Past studies on UPG congestion mitigation have primarily focused on relieving local congestion while ignoring large-scale energy transfer with safety margins and load balancing.This situation is expected to worsen with the proliferation of renewable energy and electric vehicles.In this paper,a two-layer congestion mitigation framework is proposed,one which considers the congestion of the UPG with flexible topologies.In the upper-layer,the particle swarm optimization algorithm is employed to optimize the power supply distribution(PSD)of substation transformers.This is known as the upper-layer PSD.The lower-layer model recalculates the new PSD,known as the lower-layer PSD,based on the topology candidates.A candidate topology is at an optimum when the Euclidean distance mismatch between the upper-and lower-layer PSDs is the smallest.This optimum topology is tested by standard power flow to ascertain its feasibility.The optimum transitioning sequence between the initial and optimum topologies is also determined by the two-layer framework to minimize voltage deviation and line overloading of the UPG considering dynamic thermal rating.The proposed framework is tested on a 56-node test system.Results show that the proposed framework can significantly reduce congestion,maintain safety margins,and determine the optimum transitioning sequence.

Geoctenologies Applied to Evolution in Urban Design in a City in Southern Brazil

The evolution process of urban design is the result of transformations due to population increase along the expansion of cities on a global scale.Geotechnologies applied to forms of mapping make it possible to understand the changes that have occurred in urban spaces in relation to temporal space.The general objective of this study is to analyze the change that occurred from the year 2010 to 2021,in the evolution of urban design,in the city of Marau(southern Brazil).The identification of urban evolution in the years 2010 and 2021 was carried out.These data were modeled using the QGIS software,in the SIRGAS(Geocentric Reference System for the Americas)database,related to the evolution of urban design in Marau.The results demonstrate the need to apply geotechnologies not only in the city of Marau,but in other cities worldwide,because city halls need precision maps,avoiding the fragmentation of the urban fabric,a result of population expansion not projected in the built environment.

Analysis on Regional Power Grid Load Characteristics and Rational Allocation of Capacity Load Ratio

The reasonability of the adopted capacity load ratio numerical value in urban power grid planning determines the economy of planning level yearly power grid.Too large capacity load ratio will result in the increasing investment in the early period of power grid construction, however, too small capacity load ratio will make the power grid have poor adaptability, affecting the power supply. Reasonably determining the adopted regional power grid capacity load ratio quantitative numerical value in planning has a strong guiding significance for constructing reliable and economic power grid and preventing power grid from excessive advance or lagging behind the load development. This paper, through the statistics and analysis of a certain regional power grid 2010-2012 three years＇ power grid daily load characteristics and the investment benefit evaluation of three years＇ 220KV power grid individual project, makes a preliminary analysis and puts forwards the specific advice on the reasonable values of power ~rid 35-220KV power transformation capacity load ratio.

GIS-based cost distribution analysis of new consumer connections to an urban power grid

In this paper,we propose a method of cost distribution analysis of new consumer connections to a city power grid by accounting for spatial restrictions and characteristics of existing networks.In practice,the calculation of connection costs for each new consumer includes the network design and financial expenditure.We suggest that connection costs should be calculated for the whole city based on the normative parameters at the stage when the object location is selected by investors and when power grid development is planned by power companies.The proposed method enables the modeling of new power line connection routes from every parcel of city land to possible points of connection to the operating networks based on the raster design of the area.The optimal path is chosen by one criterion consisting of two components:the costs of both laying new power lines and providing sufficient power reserve in the chosen network connection point.Realized as a computer program,the method has been used to calculate the costs of connections to low-voltage power lines.

Introduction of 35-kV kilometer-scale high-temperature superconducting cable demonstration project in Shanghai

In December 2021,the 35-kV kilometer-level high-temperature superconducting(HTS)demonstration cable was officially connected to the grid in Xuhui District,Shanghai,China.A three-in-one HTS cable with a rated current of 2.2 kA,which replaces four-parallel lines XLPE cables,has been used in this project.This cable powers one of the busiest districts of Shanghai and serves to demonstrate and study the stability and reliability of a superconducting cable in the municipal power system.This project officially started in February 2019,and the type test of the prototype cable system was completed in November 2019.The commissioning test will be completed in November 2021.This paper introduces the main operating parameters,relevant research studies,and tests of this project.

A structural project： Redevelopment of the historic center of Wuhu

Restoration and redevelopment are difficult when traces of things that require preservation have been minimized. Such operations are even more complex whenever a portion of an ancient city is involved. This essay describes the redevelopment project of the historic center of Wuhu through the different themes raised during the drafting of the project： from the cultural opportunity of a wide reconstruction work, to the definition of the main design strategies, and the question of memory and identity. The results show that the field of intervention in this project is broader than that of most restoration projects, that is, an evolving city center, which is impossible to consider with traditional restoration parameters or with pure conservation. The only possibility of interven- tion is on the city structure, which allows the city to develop itself continuously within a welt- defined system of rules.