L.C. Magrini

An experiment using an object-oriented standard-IEC 61850 to integrate IEDs systems in substations

The integration of microprocessed equipment from different manufacturers has been a difficulty in the automation of power substations, considering that the development of protocol converters is a demanding task, with questionable and costly results for the utilities. Even with the adoption of protocols that were particularly developed for the electric power sector, such as the IEC 60870-5 and the DNP, failed to solve all problems, as it only facilitates the communication between equipments, and a considerable engineering effort still must be made in the integration of such data. In response to such needs, the EPRI issued a set of recommendation standards that is now known as UCA. The IEC organization is working on the integration of UCA protocols, models and services for substations by means of the IEC 61850 standard. This article introduces the use of such protocol in substation automation from the users viewpoint, analyzing the needed requirements to implement and integrate equipments using the IEC 61850 standard.

Mobile robot for hot spot monitoring in electric power substation

This article describes the development of an unmanned monitoring system for the detection of hot spots inside a power substation. It uses an infrared camera connected to a robot which moves along the substation via a steel cable inside the substation. The robot is remotely controlled by a wireless system, operating at a frequency of 2.45 GHz (WiFi). The camera is dynamically directed to different substation components through a pan-tilt system. The whole structure is controlled by a microcomputer software located in a control room, around 200 m away from the robot. Aside of controlling the robot pan-tilt movements, the software also performs the data acquisition and analysis of thermographic images, thus detecting the referred hot spots.

A methodology for electrical energy forecast and its spatial allocation over developing boroughs

Spatial load forecasting is not an accurate subject, yet it is important for the future safe operation of a distribution system. In this paper, a methodology for spatial load forecasting based on the combination of aerial images with statically procedures applicable to developing boroughs, is presented. The core of the study underlies in the adjustment and construction of the S-curves of both saturated and non-saturated small areas. The proposed methodology is validated through the energy forecast and its spatial allocation over a pilot borough.

Distribution substation transformer and circuit breaker diagnoses with the assistance of realtime monitoring

Traditionally, transformer maintenance is done based on time, while circuit breaker maintenance is based on the number of maneuvers performed. A real-time monitoring system aims to allow the maintenance to be based on the equipments actual conditions. Real-time monitoring brings additional benefits, such as: better equipment usage, better maintenance planning, reduction of emergency impediments due to failures, and equipment life cycle management improvements. The real-time monitoring system that was designed has functionalities that assist in the diagnosis of the main equipment installed at a substation: transformers and circuit breakers.

Detection of nonconformities in monitoring system's measurements

This paper focuses on the use of intelligent computational methods and data mining technology applied to interpretation of measurements obtained from instruments of a hydroelectric dam that will signals the occurrence of an unusual value. This analysis is done considering the latest measurement collected and comparing this individual value with previous measurements already saved at historical database. This analysis is periodically done by an intelligent algorithm that produces a warning report if the latest value collected from the instrument is not compatible with the historical behavior learned from the past measurements. A modified HOT SAX algorithm is proposed for this analysis since this method was originally conceived for a fixed size time series and not for continuous data acquisition.

Point-on-wave controller developed for circuit breaker switching

The controlled switching of circuit breakers has shown to have a highly satisfactory performance for the reduction of electric transients in the electrical grid while maneuvering circuit breakers. A controlled switching device was developed for the utilization in the energization and de-energization of unloaded transmission lines as well as in the disconnection and subsequent energization of unloaded power transformers. The device was developed using a DSP (Digital Signals Processing) system which resulted from an R&D project between the University of Sao Paulo and the Electric Power Utility Company ECTE (Empresa Catarinense de Transmissao de Energia S.A.) that belongs to the TBE (Transmissoras Brasileiras de Energia) group.

Management of available power in substation transformers based on reliability

This work presents a methodology for estimating the maximum power that can be extracted from distribution substation transformers based on (i) estimated values of future load, (ii) current temperature values measured at various locations within the transformer, and (iii) transformer reliability requirements. The final goal of the methodology is to provide a sensible means of controlling transformer overloads, especially at peak times during the daily load curve. The methodology has been implemented as a software tool running on computers in the Distribution System Control Center. The software makes use of real-time data acquired directly from the local loading control subsystem installed in two major distribution substations within the CPFL (Companhia Paulistra de Forca e Luz) system.

Development of a real-time monitoring system for controlling tensioning guy wires in transmission lines

In all transmission lines in Brazil, supervision and monitoring of the towers are made through either regular inspections in the field or the identification of irregularities. In this case, the Company starts an administrative procedure or use this information for planning the next survey or even the displacement to the field for the investigation and immediately repair such irregularity. The ETEP transmission line is located in the Northern part of the country, due to its features (guyed towers and installed on land and places of difficult access), deserves special attention on the monitoring. Possible sensors and information systems were investigated and then built a prototype of real-time monitoring system which was installed on a tower. This prototype has been validated in the field. Among the issues shown in this article are: technology survey in order to monitor the tensions on guy wires; and the description of prototype validated in the field.

Electrical utilities control center data exchange with ICCP and CIM/XML

Nowadays different strategies are used to overcome the problem that electrical utility industry faces in exchanging data. To solve this problem, it is necessary to have a data format that can be accessible and readable by all electrical utilities involved in the exchanging process. In addition, the greater challenge is to enable proprietary applications to translate or access data in a generic format, common and suitable for all the utilities concerned. ICCP-intercontrol center communication protocol and CIM/XML-common information model/extensible markup language are strategies created to exchange data among the electrical utility systems. The goal of this work is to evaluate and compare the ICCP and the CIM/XML functionalities. Also, the importance of these technologies, their applicability, benefits and disadvantages are covered.

Fast system for analysis of protection events

The often unexpected load growth, failures of protection-related equipment and inadequate parameterization of protection functions make the analyses of protection events more complex and time-consuming. Besides, the amount of information that can be retrieved from modern digital relays is constantly increasing. In order to aid a quick decision-making and maintenance practices, this project aimed to implement a complete diagnosis system that is automatically activated whenever a protection-related event occurs. It covers the automation of the analysis system and the analysis system itself, which uses an expert system to process the data. It was important to observe that it is able to analyze different data sets in order to ensure the delivery of a report even when not all the expected input data is available. The system was successfully installed in a distribution substation of a Brazilian power distribution utility.