Germán Zapata

Aportes Metodológicos para el Diseño de Sistemas de Supervisión de Procesos Continuos

Resumen Se revisan los conceptos sobre la supervision de procesos y se define la terminologia y las funciones basicas de un sistema supervisor, asi como los diferentes enfoques para el diseno de dicho sistema. Se selecciona un formalismo para la representacion y modelado de la dinamica del proceso y se expresan las especificaciones desde esa base formal. La propuesta metodologica esta orientada a los sistemas convencionales, pero la representacion formal de la especificacion y el modelo del comportamiento sirven de base para agregar las funcionalidades propias de sistemas modernos de supervision inteligente. Palabras clave: supervision de procesos, supervision industrial, control supervisorio, automatizacion integrada Methodological Contributions for the Design of Supervision Systems of Continuous Processes Abstract The concepts of supervised process available in the literature are reviewed and the terminology and the basic functions of a supervisory system are defined. Also, the different approaches used for the design of such systems are analyzed. An appropriate formalism for the representation and modeling of the dynamics of the process is selected and the system specifications are expressed from that formal selected basis. The proposed methodology is focused on the conventional hierarchical systems, but both, the formal representation of the specification as well as the behavior model can be used for adding the other functionalities of other modern intelligent supervision systems.

Intelligent Production Systems Reconfiguration by Means of Petri Nets and the Supervisory Control Theory

The current trend in industrial production processes is to have agile and flexible systems that respond quickly to the permanent changes and disturbances in the production environment. This trend has created an important volume of research and papers aimed at having production control, supervision and programming systems that respond to these demands. Most of the proposals are grouped inside what has been labeled as Intelligent Manufacturing Systems (IMS). Among them are virtual, fractal, bionic, holonic manufacturing. These proposals initially appeared for discrete manufacturing processes. However, continuous production processes such as oil and gas, chemical plants, and power generation, also face demands for flexibility and rapid response. Therefore the IMS proposals can be applied to these types of processes. Holonic Production Systems (HPS) is one of the proposals that has advanced the most. It already shows evidence of its application in industrial systems. In general terms, a HPS is formed by autonomous entities that cooperate proactively to reach a common goal. These entities are labeled holons and, through aggregation relationships, they can form groups to form the so called holarchies. The grouping of various holons or holarchies with the objective of carrying out a productive process is called a Holonic Production Unit (HPU). The principal attributes of holons are: autonomy, cooperation, proactiveness, and reactivity. Other key characteristics are the distribution of intelligence and self-similarity to build complex structures from simpler systems. In order to achieve agility and flexibility, HPSs need distributed coordination and supervision functions. These functions enable them to dynamically reconfigure the production structure and the control laws to accommodate to the new operative conditions. Reconfiguration can only be faced if the production system has flexibility with regards to the allocation of manufacturing operations and of control architectures, which enable using different control policies for different types of services, or adapting control strategies to achieve new requirements.

Supervision of a distributed energy resources generation system using IEC and ISA standards

This paper develops a proposal for designing a SCADA system for the supervision of a photovoltaic generation system using IEC 61850 and ISA S101 international standards, and industrial communication protocols such as Modbus TCP and OPC. The complete description of the elements of the generating system and communication architecture for this, based on the standard IEC 61850-7-420 is performed. This standard contains the logical nodes (LNs) for modeling systems of distributed energy resources (DER). An important contribution of this work is the design of the human-machine interface (HMI) of the SCADA, which follows the guidelines of the new standard ISA S101, which makes innovative proposals for graphical display of the processes to improve situational awareness in the supervision. The standard has been proposed for industrial processes, but is expected to be adopted in the power systems supervision. Additionally, the inclusion of a section that allows to select two new modes of operation (back up and optimization), as a contribution to the objective of integration of distributed generation in existing power system to promote the transition to a smart grid is highlighted. Finally, the continuous calculation of the amount of CO2 emissions that are avoided and the update on the carbon debt caused by the use of DER sources as a contribution to improving energy efficiency and a new variable to the relevant supervision system is presented. For this job is used mature technology in the electronic component of process control so the contribution is aimed at DER sources supervision and their integration into the power system.

Transformación de requisitos representados en esquemas preconceptuales a modelos de interacción de sistemas holónicos

Holonic manufacturing systems search for improvement of the organizational productivity and elucidation of the requirements by means of strategy planning in order to reach production goals. Some architectural designs have been proposed to determine the behavior and structure of a holon. Various authors examine the development of these systems and the appropriate implementation in organizations, as suggested by the ANEMONA methodology. However, the requirements elicitation for holonic systems is a long process, whose drawbacks are found on representing and identifying holons. Pre-conceptual schemas (PS) are useful requirement elicitation tools, because they have computational tractability and they can be easily understood. In this paper we propose the representation of requirements for holons systems in PS and the formulation of conversion rules for generating the ANEMONA-based interaction model from EP. This approach is intended to improve the analysis of holonic systems in a particular domain, providing

A methodology for condition-based maintenance management in generating power plants

This paper presents a Methodology for Condition-Based Maintenance Management in Generating Power Plants. Within the frame of Smart Power Plants, this work is intended to give to the plant a proactiveness attribute. The techniques used at each stage allowing to determine the equipment condition and the maintenance suggestions are also described here. In addition, it is exposed a study case that shows its implementation in a synchronous power generator bearing system.

Online Production Scheduling and Re-Scheduling in Autonomous, Intelligent Distributed Environments

The search for the automation of continuous production systems that are widely distributed, such as: electricity, oil production, water and others, is a complex problemdue to the existence of multiple production units, transport and distribution systems, multiple points of delivery that must be coordinated, the presence of constant changes in the demand and restrictions in the production units. Automation includes constant changes in the production goals that must be captured by the system and every productionmust self-adjust to these new goals. The production re-scheduling is imperatively on line because it implies evaluating the conditions of every unit in order to know the available capacity and how feasible it is to establish physical connections amongst the different units. In order to achieve one production goal and follow the process on line, in the event of a change in demand or a failure in any unit, an adjustment in the different assignment could be reached and comply with the new conditions of the system. In order to determine the scheduling of every unit, it is important to know its available capacity, production costs and how they should work with each other in order to obtain a product. Once the scheduling is obtained, it must be monitored constantly in order to know its progress and detect when the goal cannot be reached, so a new scheduling is done. The organizational structure of the production process must allow to maintain a knowledge in every production unit, where the acquisition of information and its processing may be centralized and distributed, establishing different approaches to determine the scheduling.

Computer Tool for Analyzing Gases in Power Transformers

when the insulation of a power transformer is subjected to excessive thermal or electrical stress, the links of the chemical compounds of the oil and the cellulose in the transformer can rupture and produce different gases. The analysis of the type and concentration of these compounds may represent the state of insulation of the transformer. There are three main approaches for this analysis: Analysis of gases through traditional methods, analysis of gases through the modeling of expert knowledge, and analysis of gases according to the historical evolution of the variables. This paper presents the design and development of a tool to monitor the transformers of different power stations, applying the three analysis approaches.