Frequency Regulation with Heterogeneous Energy Resources: A Realization using Distributed Control

This paper presents one of the first real-life demonstrations of coordinated and distributed resource control for secondary frequency response in a power distribution grid. We conduct a series of tests with up to 69 heterogeneous active devices consisting of air handling units, unidirectional and bidirectional electric vehicle charging stations, a battery energy storage system, and 107 passive devices consisting of building loads and photovoltaic generators. Actuation commands for the test devices are obtained by solving an economic dispatch problem at every regulation instant using distributed ratio-consensus, primal-dual, and Newton-like algorithms. The distributed control setup consists of a set of Raspberry Pi end-points exchanging messages via an ethernet switch. The problem formulation minimizes the sum of device costs while tracking the setpoints provided by the system operator. We demonstrate accurate and fast real-time distributed computation of the optimization solution and effective tracking of the regulation signal by measuring physical device outputs over 40-minute time horizons. We also perform an economic benefit analysis which confirms eligibility to participate in an ancillary services market and demonstrates up to $53K of potential annual revenue for the selected population of devices

Rapid Frequency Response From Smart Loads in Great Britain Power System

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Sistemas de almacenamiento de Energías Renovables para la mejora de la integración en sistemas conectados a red

This document studies the problems derived from the penetration of renewable energies in an isolated distribution network. The intention of this research is to find a solution to these problems. To this end, the possibility of installing an energy storage system to help eliminate existing obstacles or, in any case, reduce them, is analyzed. This work will show how, at present, in different places this type of system is already being used to meet this objective. Likewise, all obstacles to this end are discovered and possible solutions are presented. Finally, the different types of energy storage destined to such purpose are introduced to conclude with the election of one of them and its application to an isolated distribution network, valuing its technical, economic, environmental and social impactEn este documento se estudian los problemas derivados de la penetración de las energías de origen renovable en una red de distribución aislada. La intención de esta investigación es buscar una solución a estos problemas. Para ello se analiza la posibilidad de instalar un sistema de almacenamiento energético que ayude a eliminar las trabas existentes o, en todo caso, reducirlas. En este trabajo se mostrará cómo, en la actualidad, en distintos lugares ya se recurre a este tipo de sistemas para cumplir este objetivo. Así mismo se descubren todos los obstáculos para alcanzar este fin y se presentan posibles soluciones. Por último, se introducen los distintos tipos de almacenamiento energético destinados a tal propósito para concluir con la elección de uno de ellos y su aplicación a una red de distribución aislada, valorando su impacto técnico, económico, ambiental y social

Método para alocação dimensionamento e operação de baterias em sistemas de distribuição com redução de perda e análise econômica

The use of battery energy storage systems (BESS) connected to distribution systems is analyzed. In this work these battery systems are capable of either injecting or draw power from the power systems. When such process happens at appropriate times it leads to an improvement in the electric system indicators. Two methods for optimal sizing, placement and operation schedule management of BESS are proposed aiming to get an optimal result. In this work it is desired to achieve two distinct objectives: the minimization of electrical losses from distribution systems and financial profit maximization due to BESS benefits for a distribution system over a planning horizon. The battery modeling in this paper takes into account the temporal dependency among their operational states and thus aims to portray its real operation. Such temporal dependency is dealt with sequential power flows resolutions, which respects systems operational limits. In addition, the load curve variability is considered during the process. The optimization is performed through two proposed methods, the first one is an straight search procedure that aims to solve all the problem variables simultaneously The second is an iterative search procedure that defines BESS operation schedule through an optimization process and uses another one to set his sizing and placement. Both proposed methods uses Genetic Algorithms as an optimization tool. Results obtained from simulations in different power systems are presented to demonstrate the applicability of the proposed method.Neste trabalho é analisado o uso de sistemas de armazenamento de energia por baterias (BESS) em sistemas elétricos de distribuição. Esses sistemas de baterias são capazes de injetar ou absorver energia dos sistemas de distribuição. Quando tal processo é realizado em momentos propícios, proporciona uma melhora nos indicadores dos sistemas elétricos. São propostos dois métodos para alocar, dimensionar e gerenciar a operação destes conjuntos de baterias, visando obter um resultado ótimo. Neste trabalho, deseja-se alcançar dois objetivos distintos: a minimização das perdas elétricas do sistema de distribuição e a maximização do retorno financeiro, decorrente do benefício dos BESS a um sistema ao longo de um horizonte de planejamento. A modelagem de bateria utilizada considera questões de dependência temporal entre seus estados de operação e, assim, visa retratar seu funcionamento real. Tal dependência temporal é abordada pela resolução de fluxos de potência sequenciais, que respeitam os limites operativos dos sistemas. A otimização é realizada através de dois métodos propostos, o primeiro é um procedimento de busca direta, que visa solucionar todas as variáveis do problema simultaneamente. O segundo é um procedimento de busca iterativa, que define o cronograma de operação por meio de um processo de otimização e utiliza outro processo para alocar e dimensionar os BESS. Ambos os métodos propostos utilizam o algoritmo genético como ferramenta de otimização. Resultados obtidos em simulações de diferentes sistemas de distribuição são apresentados para demonstrar a aplicabilidade do método proposto.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Power System Frequency Measurement Based Data Analytics and Situational Awareness

This dissertation presents several measurement-based research from power system wide-area dynamics data analytics to real-time situational awareness application development. All the research are grounded on the power system phasor measurements provided by wide-area Frequency Monitoring Network (FNET/GridEye), which collects the Global Positioning System (GPS) signal synchronized power system phasor measurements at distribution networks. The synchronized frequency measurement at FNET/GridEye enables real-time monitoring of bulk power systems (BPSs) and allows the dynamics interpretation of power system disturbances. Research on both the dynamic and ambient frequency measurements are conducted in this dissertation.The dynamics refer to the frequency measurement when the system is experiencing sudden contingencies. This dissertation focuses on two types of contingency: generation trip and oscillation and conducts both data analytics and corresponding real-time applications. Historical generation trip events in North America are analyzed in purpose to develop a frequency measurement based indicator of power systems low inertia events. Then the frequency response study is extended to bulk power systems worldwide to derive its association with system capacity size. As an essential parameter involved in the frequency response, the magnitude of the power imbalances is estimated based on multiple linear regression for improved accuracy. With respect to situational awareness, a real-time FNET/GridEye generation trip detection tool is developed for PMU use at power utilities and ISOs, which overcomes several challenges brought by different data situations.Regarding the oscillation dynamics, statistical analysis is accomplished on power system inter-area oscillations demonstrating the yearly trend of low-frequency oscillations and the association with system load. A novel real-time application is developed to detect power systems sustained oscillation in large area. The application would significantly facilitate the power grid situational awareness enhancement and system resiliency improvement.Furthermore, an additional project is executed on the ambient frequency measurement at FNET/GridEye. This project discloses the correlation between power system frequency and the electric clock time drift. In practice, this technique serves to track the time drifts in traffic signal systems