Optimal Design of Hybrid Microgrid in Isolated Communities of Ecuador

In rural territories,the communities use energy sources based on fossil fuels to supply themselves with electricity,which may address two main problems:greenhouse gas emissions and high fuel prices.Hence,there is an opportunity to include renewable resources in the energy mix.This paper develops an optimization model to determine the optimal sizing,the total annual investment cost in renewable generation,and other operating costs of the components of a hybrid microgrid.By running a k-means clustering algorithm on a meteorological dataset of the community under study,the hourly representative values become input parameters in the proposed optimization model.The method for the optimal design of hybrid microgrid is analyzed in six operating scenarios considering:(1)24-hour continuous power supply;(2)load shedding percentage;(3)disel power generator(genset)curtailment;(4)the worst meteorological conditions;(5)the use of renewable energy sources including battery energy storage systems(BESSs);and(6)the use of genset.A mathematical programming language(AMPL)tool is used to find solutions of the proposed optimization model.Results show that the total costs of microgrid in the scenarios that cover 100%of the load demand(without considering the scenario with 100%renewables)increase by over 16%compared with the scenario with genset operation limitation.For the designs with power supply restrictions,the total cost of microgrid in the scenario with load shedding is reduced by over 27%compared with that without load shedding.

Fault Location Approach to Distribution Networks Based on Custom State Estimator

This paper presents a properly designed branchcurrent based state estimator(BCBSE)used as the main core ofan accurate fault location approach(FLA)devoted to distribution networks.Contrary to the approaches available in the literature,it uses only a limited set of conventional measurementsobtained from smart meters to accurately locate faults at busesor branches without requiring measurements provided by phasor measurement units(PMUs).This is possible due to themethods used to model the angular reference and the faultedbus,in addition to the proper choice of the weights in the stateestimator(SE).The proposed approach is based on a searchingprocedure composed of up to three stages:①the identificationof the faulted zones;②the identification of the bus closest tothe fault;and③the location of the fault itself,searching onbranches connected to the bus closest to the fault.Furthermore,this paper presents a comprehensive assessment of the proposedapproach,even considering the presence of distributed generation,and a sensitivity study on the proper weights required bythe SE for fault location purposes,which can not be found inthe literature.Results show that the proposed BCBSE-basedFLA is robust,accurate,and aligned with the requirements ofthe traditional and active distribution networks.