Bad data identification when using ampere measurements

IEEE/PES TRANSMISION AND DISTRIBUTION CONFERENCE AND EXPOSITION (.1996.DENVER)Earlier papers have shown that the use of power system line current magnitude measurements may lead to nonuniquely observable systems. This paper studies the bad data identification problem under these conditions. The definition of measurement criticality is revised in order to account for the nonuniquely observable cases. The problem of bad data identification is investigated both as a post estimation problem when using the least squares estimation method and as an outlier rejection problem when using the least absolute value estimation method. Modifications to the existing bad data processing methods are proposed in order to account for the current magnitude measurements

A Comparison Between Kalman Filters and STDFT for Harmonic Estimation in Power Systems

5th WSEAS/IASME Int. Conf. on Electric Power Systems, High Voltages, Electric Machines, Tenerife, Spain, December 16-18, 2005This paper presents a comparison between Kalman filter and the running DFT for the computation of harmonics in power systems applications. The performance of both filters is compared for events like voltage dips or those in which a decaying DC component is present. The comparison considers also the presence of higher order harmonics

An efficient ordering algorithm to improve sparse vector methods

This paper presents a new node ordering algorithm to enhance sparse vector methods. The proposed technique locally minimizes the number of non-zero elements of the inverse of the table of factors. It uses the cardinality of the set of nodes which precede each node in the path graph as a tie-break criterion in the minimum degree elimination process. Test results are included showing that the method performs better than previously published methods.IEEE Power & Energy Societ

Multi-Processor Architectures for Solving Sparse Linear Systems. Application to the Load Flow Problem

IFAC SYMPOSIUM ON COMPONENTS,INSTRUMENTS AND TECHNIQUES FOR LOW COST AUTOMATION AND APPLICATIONS.1986 (.1986.VALENCIA)Three heuristic algorithms for solving a cluster problem associated with the tearing of a symmetric matrix are presented. Based on these partitioning procedures, a method for the parallel solution of the fast decoupled load flow has been developed, although it is also suitable for the parallel solution of any linear equations system. Experimental results of applying such algorithms on several test systems have been obtained using a multiprocessor architecture

State Estimation in Two Time Scales for Smart Distribution Systems

The monitoring of distribution systems relies on a critical set of pseudomeasurements and a varying but low number of redundant measurements. In the light of the different refreshing rates of both types of information, this paper considers a state estimation model structured in two time scales. Possibilities and limitations of the proposed model are discussed, and illustrated on a real distribution system comprising a diversity of load patterns

Offset-Assisted Factored Solution of Nonlinear Systems

This paper presents an improvement to the recently-introduced factored method for the solution of nonlinear equations. The basic idea consists of transforming the original system by adding an offset to all unknowns. When searching for real solutions, a real offset prevents the intermediate values of unknowns from becoming complex. Reciprocally, when searching for complex solutions, a complex offset is advisable to allow the iterative process to quickly abandon the real domain. Several examples are used to illustrate the performance of the proposed algorithm, when compared to Newton’s methodMinisterio de Economía y Competitividadt ENE2013-48428-C

Three methods for the parallel solution of a large, sparse system of linear equations by multiprocessors

In this paper three methods for the parallel solution of large-scale, sparse, linear equation systems are presented and compared. Both, factorization of the matrix and forward backward. Processes have been considered. A multiprocessor architecture has been simulated and results are presented corresponding to eight examples taken from power systems field, ranging from 117 to 660 equations

Modelado y análisis de la evolución de una epidemia vírica mediante filtros de Kalman: el caso del COVID-19 en España

Documento de trabajo. Difundido en idUS a solicitud de los autoresEste trabajo presenta una metodología original para el tratamiento de los datos reportados de positivos y fallecidos por una epidemia vírica. El objetivo principal es caracterizar la evolución de la progresión del número de infectados reales, y en consecuencia poder predecir en qué momento se alcanzará el pico de la epidemia en un caso de estudio concreto, en este caso la del Covid-19 en España. Los resultados obtenidos muestran claramente el efecto beneficioso de las medidas de confinamiento adoptadas, y prevén que el pico se producirá aproximadamente a finales de marzo o principios de abri

Robustness of electricity systems with nearly 100% share of renewables: A worst-case study

Several research studies have shown that future sustainable electricity systems, mostly based on renewable generation and storage, are feasible with today's technologies and costs. However, recent episodes of extreme weather conditions, probably associated with climate change, cast shades of doubt on whether the resulting generation portfolios are sufficiently robust to assure, at all times, a suitable balance between generation and demand, when adverse conditions are faced. To address this issue, this work elaborates a methodology intended to determine a sustainable electricity generation system, that can endure extreme weather conditions which are likely to occur. First, using hourly production and demand data from the last decade, along with estimates of new uses of electricity, a worst-case scenario is constructed, including the storage capacity and additional photovoltaic power which are needed to serve the demand on an hourly basis. Next, several key parameters which may have a significant influence on the LCOE are considered, and a sensitivity analysis is carried out to determine their real impact, significance and potential trends. The proposed methodology is then applied to the Spanish system. The results show that, under the hypotheses and conditions considered in this paper, it is possible to design a decarbonized electricity system that, taking advantage of existing sustainable assets, satisfies the long-term needs by providing a reliable supply at an average cost significantly lower than current market prices.Agencia Estatal de Investigación (AEI) PID2020-116433RB-I00Centro para el Desarrollo Tecnológico Industrial (CDTI) España CER-2019101