Rafael Milbradt

Real-time evaluation of voltage control in distribution systems using remote measurements and smart meters

The recent technological advances included in the distribution systems, such as the use of supervisory systems, automation and the emergence of the smart meters brings many possibilities for improvement in the methodologies used in the operation of these systems. This paper proposes a methodology for using state estimation techniques and error detection in smart grids, through measures in the MV network and smart meters to evaluate the voltage profile of the feeder. This evaluation is obtained by calculating an index that analyzes the voltage levels at nodes of consumers according to the ranges appropriate, precarious and critical, further penalizing violations in loads with higher priority or that are in this condition for a long time. The methodology for evaluation can be used to predict the scenarios when changing settings in voltage regulators, seeking to supply energy with a higher quality, thereby increasing consumer satisfaction.

A multicriteria approach for meter placement in monitoring of smart distribution systems

One of the principles of Smart Grids is to have a communication network that will integrate equipment allowing the monitoring and operation to be performed in real time in order to improve the quality indicators. However, this migration to an automated and monitored environment will demand many resources that will be used to perform the migration gradually. Therefore, this work proposes a methodology for allocation of meters with the function of improving the accuracy of state estimation algorithms, but also considering other selection criteria, given the fact that many of automation equipment such as reclosers, automated switches, voltage controllers also perform the function of meters. The paper demonstrates the implementation of a state estimator based on the WLS method, which serves as the basis for the analysis of quantitative criteria such as the accuracy of the estimator, losses, voltage levels and reliability. Thus, the criteria are analyzed considering the needs defined by experts through the Analytic Hierarchy Process, so alternatives of locations and equipment can be prioritized. Finally, the methodology is demonstrated by experimental evaluation on a real feeder.

Cyber security and communications network on SCADA systems in the context of Smart Grids

The implementation of Smart Grids demands two-way communication mechanisms between the several network devices and the SCADA systems. This communication converges to use of IP based networks, which brings gains due to the wide use of this type of network. However, also brings the security concerns inherent the communications networks. In function on the criticality of power systems, provide a reliable and secure communication system are fundamental premises for your seemly operation. Because the diversity of devices from different manufacturers utilized in the power system are necessary mechanisms more generic to provide security. Thus, able provide security even at legacy devices without replacing it. To achieve it, this work proposes an architecture using security middleware SECOM that aims to make secure communications between supervisory systems and the IEDs. Therefore, avoiding denial of service attacks (DoS). This is possible because it manages issues about authenticity, integrity and confidentiality from communication networks.

Methods of availability assurance for communication of PMU in a smart grid based on IP protocol

Communication networks consist of a crucial tool for the implementation of Smart Grids. The different kinds of data flowing in a Smart Grid have different latency and reliability requirements. Phasor Measurement Units (PMU) are becoming increasingly widespread like instruments to monitoring of electrical distribution systems. The use of this equipment has severe restrictions on bandwidth, latency and packet loss. The trend for the use of IP networks makes imperative the use of mechanisms to ensure treatment to these requirements within implementations of Smart Grids. This paper realizes an approach of QoS mechanisms available to increase the availability and reliability in the context of PMU applications within Smart Grids.

A multicriteria approach for meter placement in distribution systems

One of the principles of Smart Grids is to have a communication network that will integrate equipment allowing the monitoring and operation to be performed in real time in order to improve the quality indicators. However, this migration to an automated and monitored environment will demand many resources that will be used to perform the migration gradually. Therefore, this work proposes a methodology for allocation of meters with the function of improving the accuracy of state estimation algorithms, but also considering other selection criteria, given the fact that many of automation equipment such as reclosers, automated switches, voltage controllers also perform the function of meters. The paper demonstrates the implementation of a state estimator based on the WLS method, which serves as the basis for the analysis of quantitative criteria such as the accuracy of the estimator, losses, voltage levels and reliability. Thus, the criteria are analyzed considering the needs defined by experts through the Analytic Hierarchy Process, so alternatives of locations and equipment can be prioritized. Finally, the methodology is demonstrated by experimental evaluation on a real feeder.

Implementing a distributed firewall using a DHT network applied to Smart Grids

This paper is a part of a research and development program conducted by Federal University of Santa Maria (UFSM) and the Distribution System State Company (CEEE-D) located in South of Brazil. The purpose of this paper is present a communication architecture for Smart Grids that uses a distributed firewall. The synchronization of rules and policies among them, it was developed a methodology that uses the structure of a DHT (Distributed Hash Table) network.

Methodologies for the development of a central control system in a smart grid environment based in free softwares

Actual electric network infrastructure is poorly adapted to the new requirements of the society for reliability, efficiency and sustainability. Thus, it must undergo an intense modernization in the next years, becoming smart, also known as Smart Grids. In this Smart Grid context, computer systems will be a key hole in the analysis and monitoring of several devices that are connected to the grid. This work presents a Geographic Information System (GIS) and a central control system for distribution networks, the ASW. The communication of this system via MODBUS protocol with SCADA System is also shown, the latter being responsible for operating and acquiring real time data from a voltage regulator controller. The chosen SCADA system for the methodology proposed in this paper is based on free software technologies, which allows for new functions and methods to be incorporated, in order to build new and fully customized tools. The methods proposed here applied with success are expected to be replicable in others smart grids researches.

Alternatives for voltage control in the scenario of Smart Grids

Before the deployment of Smart Grids the quality of voltage is replaced by a new focus, because the regulator is able to improve the activity, the user has access to the value of the voltage in real time and the distributor, in turn, needs to meet the regulatory actions and expectations of its customers. Nowadays in conventional networks the voltage adjustment is performed from the reference voltage set point of itself, as in the scenario of Smart Grids beyond this value is also possible to use the records of voltage of other feeder points. In this new scenario is appropriate to identify alternatives related to voltage control in distribution networks, in this way, the present work presents the forecast of voltage for monitoring points located throughout the electrical system. From the results obtained for the prediction is introduced the concept of intelligent control. The presented methodology considers the taking of proactive actions and proposes the development of a tool to support the operating voltage control in real time.