PMU-based informational support of power system control tasks

Up-to-date wide area measurement systems (WAMS) based on phasor measurement units (PMU) appeared at the very end of the 20th century. Under present-day conditions, WAMS serve as the basis for information-measuring systems, which significantly improve power system control and operation. In practice, WAMS are mostly used for power system stability control and transient monitoring and visualization. This paper discusses the new opportunities for power system control quality improvement, resulting from PMU application for power system steady-state parameters' assessment. Firstly, better control is provided by online equivalent circuit parameters' identification using PMU measurement data and taking into account FACTS and other shunt and series compensation equipment. Secondly, the paper addresses the problems of "nodal" identification, which have taken on great importance recently due to the intensive development of small-scaled distributed generation. Based on PMU measurements of nodal voltages and incident transmission lines' electric currents, one can obtain online steady-state load characteristics, which can be used for dispatch control applications. Moreover, PMUs provide superaccelerated power flow calculations, which are of crucial importance for emergency automation, adjusted for prior operation. Such principles of emergency automation consist of the quick determination of control actions, aimed at power system stability maintenance in cases of any programmed faults' occurrence. It is known that such control is carried out by means of power flow calculations based on remote metering data. The proposed application and allocation of PMUs in the power system by means of combinatorial matrix transformation to triangle form give the possibility to perform accelerated node-voltage analysis without equivalent circuit simplification. All the calculations are verified using IEEE test networks. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

A PRIORI TELEMETRY FILTERING AND POWER SYSTEM STATE ESTIMATION USING PHASOR MEASUREMENTS

Основным инструментом повышения достоверности телеметрии в энергетических системах является оценивание состояния (ОС). Априорное выявление ошибочных данных до этапа ОС ведет к значительному повышению достоверности параметров режима, снижению времени расчета, что имеет особую важность для энергосистем большой размерности. Особенностями предлагаемой априорной фильтрации является простота и небольшой объем вычислений. Внедрение технологии синхронизированных векторных измерений на базе PMU позволяет использовать высокоточные данные PMU, совместно с традиционными данными SCADA при решении задачи ОС. Наличие устройств PMU даже в нескольких узлах энергосистемы дает возможность существенно повысить эффективность ОС.The state estimation is a basic instrument of the power systems telemetry validation increase. An a priori data errors detection prior to the state estimation leads to the significant steady state parameters validation increase and calculation time decrease. It is of great importance for the large-scale power systems. The proposed a priori filtration features are simplicity and small volume of calculations. The PMU-based phasor measurements technology implementation allows the cooperative use of high-precision PMU data along with conventional SCADA data within the state estimation task solution. The PMU presence even in few power system nodes allows the significant state estimation efficiency increase

Estimação de estados em sistemas com dispositivos TCSC via método desacoplado-rápido modificado

Orientadora: Elizete Maria LourençoCoorientador: Odilon Luis TortelliDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Elétrica. Defesa : Curitiba, 28/07/2020Inclui referências: p. 148-153Área de concentração: Sistemas de EnergiaResumo: A recente popularização e crescente inserção de controladores FACTS nos sistemas de potência ao redor do mundo ensejou a necessidade de modelar e inserir tais dispositivos nas metodologias tradicionalmente empregadas na operação e análise de sistemas de energia. O conceito de FACTS está diretamente relacionado ao aprimoramento dos sistemas existentes, tornando-os eletronicamente controláveis. São dispositivos que atuam ativamente no controle das principais grandezas do sistema de forma a flexibilizar sua operação, uma oportunidade especialmente relevante um contexto de Smart Grid. O presente trabalho de pesquisa se concentra na estimação de estados de sistemas de potência que contém dispositivos FACTS, especificamente o controlador TCSC, propondo duas abordagens distintas para tratar o problema de estimação de estados em sistemas em que o referido controlador é inserido. A primeira abordagem proposta se refere à adaptação da formulação de mínimos quadrados ponderados linearizada do problema de estimação de estados, com intuito de inserir o parâmetro de controle do TCSC como uma nova variável de estado para o problema, a ser estimada em conjunto com as variáveis de estado tradicionais do modelo linearizado da rede. A segunda abordagem proposta diz respeito a um estimador de estado baseado na formulação desacoplado-rápido do método de mínimos quadrados ponderados, capaz de processar conjuntos de medidas obtidos de sistemas de transmissão que contém o controlador FACTS TCSC. As reatâncias equivalentes dos controladores são inseridas como novas variáveis de estado no subproblema ativo da formulação desacoplado-rápido, sendo estimadas em conjunto com as variáveis de estado tradicionais do sistema. Além fornecer uma estimativa dos parâmetros de controle dos TCSCs e variáveis de estado tradicionais a partir de um conjunto de medidas obtidas pelo sistema SCADA, as abordagens propostas possuem aplicações na determinação das reatâncias equivalentes dos controladores necessárias para que sejam mantidos os fluxos de potência ativa especificados para os ramos controlados, considerando os modelos linear e não linear da rede. Os resultados apontam para uma boa aplicabilidade dos métodos propostos, capazes de estimar com precisão e eficiência os parâmetros de controle dos TCSCs sob diferentes condições operativas para diferentes sistemas-teste de transmissão. Palavras-chave: Estimação de Estados. FACTS. Thyristor Controlled Series Capacitor. Método Desacoplado-Rápido. Sistemas de Transmissão.Abstract: The recent popularization and increasing insertion of FACTS controllers in power systems gave rise to the need for modeling and inserting such devices in the traditional power system analysis and operation applications. The concept of FACTS is directly related to the improvement of existing installations, making them electronically controllable. FACTS controllers provide active control of many of the power system magnitudes, which flexibilities the system operation with especially relevant opportunities in the Smart Grid context. The present research work focuses on the state estimation of power systems with FACTS, specifically the TCSC controller, proposing two different approaches to address the state estimation problem for power systems with TCSC. The first proposed approach refers to an adaptation of the linearized weighted least squares formulation of the state estimation problem, in which the TCSC's control parameter is inserted as a new state variable for the linearized state estimation problem, being estimated together with the traditional state variables of the linearized power system model. The second proposed approach concerns to an adaptation of the weighted least squares fast-decoupled state estimator, capable of processing measurements obtained from transmission systems with TCSC. The controllers' equivalent reactances are inserted as new state variables in the active subproblem of the fast-decoupled formulation, being estimated together with the traditional state variables of the system. Besides providing an estimate of the control parameters of the TCSCs and traditional state variables from a set of measurements obtained by the SCADA system, the proposed approaches have applications in determining the necessary controllers' equivalent reactances to maintain the desired active power flows through controlled branches, considering the linear and non-linear models of the network. The results point to good applicability of the proposed methods, which are capable of estimating the control parameters of the TCSCs with accuracy and efficiency, under different operating conditions for different transmission systems. Keywords: State Estimation. FACTS. Thyristor Controlled Series Capacitor. Fast- Decoupled Method. Transmission System

New information technologies for state estimation of power systems with FACTS

It is known, that Flexible Alternating Current Transmission Systems (FACTS) are the core of the High Voltage Smart Grid technologies. Wide Area Measurement Systems (WAMS), using Phasor Measurement Units (PMU), open up new opportunities for power system monitoring and control. United Power System of Russia, having high generating capacities, is the most extensive power system in the world, stretching for thousands of kilometers through 7 time zones. For these reasons, close attention have always been paid to long-distance power transmission issues. This paper presents the methodology for data validation improvement for real-time power system monitoring and assessment of long-distance power transmission lines parameters, including controllable series and shut reactive power injection. The basis for data validation is two-stage a priori remote metering processing, including load- and weather-dependent transmission line parameters identification and update as well as local bad data elimination. © 2012 IEEE

New information technologies for state estimation of power systems with FACTS

It is known, that Flexible Alternating Current Transmission Systems (FACTS) are the core of the High Voltage Smart Grid technologies. Wide Area Measurement Systems (WAMS), using Phasor Measurement Units (PMU), open up new opportunities for power system monitoring and control. United Power System of Russia, having high generating capacities, is the most extensive power system in the world, stretching for thousands of kilometers through 7 time zones. For these reasons, close attention have always been paid to long-distance power transmission issues. This paper presents the methodology for data validation improvement for real-time power system monitoring and assessment of long-distance power transmission lines parameters, including controllable series and shut reactive power injection. The basis for data validation is two-stage a priori remote metering processing, including load- and weather-dependent transmission line parameters identification and update as well as local bad data elimination. © 2012 IEEE