SNPTEE
NATIONAL SEMINAR OF PRODUCTION AND TRANSMISSION
OF ELECTRIC ENERGY
October 16 to 21, 2005 - Curitiba – Paraná - Brazil
GROUP IX
ELECTRIC SYSTEMS OPERATION GROUP - GOP
PHOENIX SYSTEM:
MAINTENANCE AND OPERATION MANAGEMENT OF SUBSTATION EQUIPMENT
Gilberto José Rigotto Jr * Izonel Henrique Pereira Jr João Luiz de Oliveira Gomes
CEMIG DISTRIBUTION CEMIG DISTRIBUTION CEMIG DISTRIBUTION
Marilene Ângela da Cruz Jeder Francisco de Oliveira André Luiz Medeiros Costa
CEMIG DISTRIBUTION CEMIG TRANSMISSION CEMIG TRANSMISSION
ABSTRACT
Phoenix System was created in order to facilitate the management of technical information on substation equipment, thus integrating outdated systems of operation (Relays Database – BDR) and maintenance (Maintenance and Testing Results - RME), standardizing methods and optimizing procedures, besides being suitable for connection with technical and corporate information systems, such as Geoprocessing, GEDOC and SAP-R3™. Phoenix System was developed in Windows and SQL-server environment and uses the experience obtained with the old systems by keeping their good features and correcting errors. Its creation was possible thanks to the widening of the corporate microcomputer network – Intranet and the favorable IT environment. It utilizes descriptions of equipment of the old systems and promotes business gains.
KEY WORDS: Integration; Database; Computerized Management System; Equipment; Operation; Maintenance.
1.0 – INTRODUCTION
Electric energy utilities, while expanding and acquiring assets, have begun to feel the need to have control on technical information about their equipment, within the several internal areas, towards controlling, facilitating and improving their work methods. Substation operation and maintenance areas, generally in different departments of the same company, require technical data on equipment so as to perform their specific activities. Such data are used not only for typical electric operation studies, including: calculation of short circuits; protection settings; power flows; electromagnetic transients; admissible transformer load; transmission line switching and others; but also for maintenance control and support: maintenance instructions; testing record sheets; testing acceptable limits; automated tests.
In CEMIG, two computer systems have been separately developed for protection and control equipment in distinct environments, aiming to meet specific needs of the areas of operation and maintenance of protection and control relays, by covering the same equipment.
The Database of Relays – BDR in IDMS or IBM Mainframe environment was created in 1970. Its main objectives were having a single basis to calculate relay settings and being accessible by the company’s main operation departments. It was accomplished through the Mainframe, which is made up of a single large central unit for data processing and storage, located in the head-office, with terminals spread throughout the company. The Service Orders (PS’s) informing the settings that should be made in the relays by the maintenance area were generated through this database, being easily controlled by password for insertions, alterations, exclusions and references, including their history. The description of the relays was made through a template with blanks to be filled in with the calculated settings. The Service Order was then printed and sent in hard copy to the maintenance area that, upon making the settings and testing the relay(s), replied the PS with information related to the service execution.
The computer system Equip was created to support the other electric operation studies, containing the location and identification of transformation and switching equipment as well as some of their electrical features required for these studies, such as impedances, rated and admissible powers, rated current, symmetrical interrupting capacity, among others.
In the 90 decade, the maintenance area created the RME – Specialized Maintenance System, initially intended to give support to protection and control maintenance, and later including transformers and switches. The RME was born at a time when the extensive use of personal computers in the companies was beginning and therefore its development was driven towards this kind of environment, with the use of current software available for database management.
At a given moment such solutions became outdated, as new hardware and software solutions were made available. CEMIG’s centralized operation and maintenance areas designed a new system for the integrated management of substation equipment and support to those activities. The new system was named Phoenix in reference to the mythological bird that reborns from its own ashes into a renewed and long living creature.
Phoenix System is intended to be an essential tool for maintenance execution, thus ensuring that data are continuously updated. Therefore, the system contributes to updating information about equipment within the corporate system SAP R3™. The use of Phoenix is going not only to avoid rework related to the insertion of protection relays settings data and the creation of templates, but also make possible other gains as described in this work. On the other hand, it is going to face challenges for the description and inclusion of all digital relays installed in the company, which are not controlled by any databases.
2.0 – HISTORY
2.1 Database of Relays – BDR
The BDR is a system designed to control models, settings and service orders related to protection relays, which was developed in the IBM environment and has been adopted in CEMIG for more than 20 years. By the time the system was conceived, it resulted in considerable gains not only to the operation engineering and maintenance areas but also to field teams, since information started to be centralized. Some advantages can be outlined, such as the control, through a centralized database, of Service Orders for Protection Settings issued by the area of operation studies as well as its accessibility from any location where an IBM terminal was available. However, with the technological innovations the BDR started to present some problems, regarding both the system itself and the relays. In terms the system’s weaknesses, it is outdated, its maintenance is difficult to be executed, and IBM has recently informed that they are not going to provide support to the system through which BDR is running. Regarding the relays, with the emergence of micro-processed equipment the BDR turned out to be a hindrance for the description of some relays, since the system has a limitation on the maximum number of allowed parameter data.
2.2 Specialized Maintenance System – RME
RME is a system dedicated to support substation equipment maintenance of CEMIG power system. It was implemented in 1992, with the utilization of Clipper and C languages in the DOS operational system. In 2001 the system migration to Windows was contracted. RME system is used both for the execution of preventive and corrective maintenance tests and for commissioning tests in new equipment. This system was created by the protection and control maintenance team, in face of the need to support relay maintenance activities. Afterwards, due to its successful operation, it was expanded to other kinds of substation equipment, mainly transformation and switching ones. Significant adaptations were not required: it was found that the functionalities developed for relays were suitable for the maintenance of the remaining equipment.
The system provides a test data sheet for each equipment model to be maintained. This record sheet is a result of a prior standardization of the equipment as well as individual settings at each operation point: the system calculates the admissible values for each adjustment according to the value of the actual setting and to the manufacturer’s instructions. It works as a guide to maintenance crew and, along with maintenance instructions, it makes possible to conduct all tests in a standardized and personalized way according to the operation point. The user records the maintenance results in the data sheet and, when it is possible to access a computer terminal with the RME installed, the recorded results are inserted in the system. The system keeps the history of maintenance and testing results per equipment, codified through an identification sequence numbering generated by CEMIG.
The system installation in the user’s computer uploads the entire database of equipment models and maintenance instructions, besides the control applications. By the time the system was developed, there was not a corporate computer network, so a systematic procedure was created in order to allow centralized control and access to all maintenance activities executed in the company. The application in the user’s computer exports its database to a file, which is sent to the central unit from where it is imported to the historical and corporate database. This procedure causes problems, such as:
• too much time spent to export and import from the database;
• multiple databases in the several users’ computers, thus making data exchange difficult and often leading to unrecoverable losses;
• every new version of the application has to be installed in all machines;
• since the user does not depend on the recorded results, he ends up either not typing them or delaying their insertion, which renders the system unreliable;
• the quantity of data in the database is limited by the software management capacity.
2.3 Favorable Environment for Integration
A number of structural conditions led the operation engineering and maintenance areas to search for a new integrated solution for the technical management of the substation equipment as well as for a support to their activities.
• With the migration of the IBM-based systems to the computer network, CEMIG decided to deactivate that environment and scheduled a date to disable the BDR.
• Digital technology has totally dominated the protection and control relays since the mid 90’s. With the integration of functions into a single unit, which is characteristic of this type of technology, the description of relays became impossible through the BDR.
• The procedures adopted for issuing, printing, approving, sending, executing and replying Service Orders were outdated when compared to the currently available IT and communication resources. The reduction in the number of technical and administrative employees, associated with the expansion of the power system and the digital relays technology require the review, standardization and simplification of such procedures.
• The RME system application depended on external maintenance services contracted by CEMIG.
• The decentralization of the RME database caused so many problems that some users stopped using it to control maintenance results and started using just the test data sheets and the maintenance instructions.
• The current information environment, for instance the WEB, the INTRANET, the increasingly powerful database engines, the corporate system SAP R3™, has created highly favorable conditions to meet the objectives related to substation operation and maintenance, by assuring information reliability and safe access to databases in almost all company’s instalations. Moreover, more powerful microcomputers, laptops and handhelds have opened up new possibilities.
• The experience acquired with the design and utilization of the previous systems makes the specification of the new system easier.
3.0 – REQUIREMENTS ON THE PHOENIX SYSTEM
The Phoenix System was designed to meet some requirements so as to prevent the multiplication of subsystems, to standardize data and to serve all users. As a system of this size, accessible to all the company, requires accurate specification and detailed procedures, the parameters below were established:
• The first decision is that the technical database should be unique in the company. Previously, a proliferation of databases describing the same equipment was detected, which caused rework and lack of standardization.
• Non-overlapping with other systems, such as SAP, Geo-referenced Information System - GeoCEMIG, Electronic Management of Documents - GEDOC: creation of connections between the systems without overlapping functions, however integrating them and optimizing the use of information.
• Information security is guaranteed in the IT area through control centralization, automatic and frequent backups and, regarding users, privilege control with the creation of users’ profiles hierarchically organized and controlled by the system managers.
• Support to all operation and maintenance users: creation of specific functionalities for the areas, thus meeting the needs of their relevant processes.
• Data update assured by the necessity of using the system as a work tool for the execution of field activities, in which the direct contact with the equipment feeds the system on an ongoing basis.
• The technical and legal responsibilities of each area are controlled through the traceability of the person in charge of each service phase: calculation of settings, PS approval, PS implementation in the equipment, preventive and corrective maintenance services.
• The system must be entirely under CEMIG’s technological domain, thus eliminating any possibility of external dependence.
• Utilization of data from previous systems: standardization of models, test data sheets, maintenance instructions, adjustment values, and historical data.
4.0 - PHOENIX SYSTEM OPERATION FUNCTIONALITIES
The Phoenix System was designed in order to allow personal access, according to the user’s profile. Some user profiles were defined, with the possibility of adding some activities that can also be performed. This permitted keeping the standardization while assigning some activities to a limited number of people.
Instalation structure used for database design is showed in Figure 1, in a simplified way.
Figure 1 Instalation database structure of Phoenix Sustem
The first hierarchy level is used to store the instalations, and these are going to be recorded in the system through a table originated from the MySAP system, which is also used in the company.
The second level is used to store all the facility components, such as transmission lines, transformers, capacitor banks, etc.
The third level is used to store the operative points of the component, as showed in Figure 1.
Finally, in the fourth level the protection relays are represented, which might be connected to more than one operative point, a situation that can occur in practice.
Regarding the service orders – PS’s, some types were defined with some individual characteristics, such as first setting, readjustment and temporary readjustment. Several different files can be attached to the PS, such as the files containing relay parameters and settings, kept indefinitely, turning into the only source where relay settings made will be found, besides the relay itself. There is still a possibility of including e-mail adresses to send warnings, besides those that the system forwards automatically, as well as including other related service orders.