http://www.ifac-papersonline.net/ en Copyright 09:59 PM Tuesday 09, 2010 IFAC-PapersOnline http://www.ifacpapersonline.com 09:59 PM Tuesday 09, 2010 09:59 PM Tuesday 09, 2010 ET webmaster@ifac-papersonline.net webmaster@ifac-papersonline.net http://www.ifac-papersonline.net/Detailed/39488.html 04:00 PM Wednesday 31, 1969 http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39539.html 04:00 PM Wednesday 31, 1969 The promotion of energy production from renewable resources represents an imperative objective in present times justified by environmental issues, the increase of energetic independence by avoiding imports, supplying a diversity of sources and of course economical and social cohesion reasons. Management and supervising schemes for the systems based on renewable resources are a requirement in order to insure their energetic efficiency and operation. This paper presents some of the required energy management principles. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39519.html 04:00 PM Wednesday 31, 1969 Inverters with capacitive loads or with additional series capacity and which assure a capacitive current through series circuit usually determine observance of return time, and reactive power delivered by load is adequate for commutation of thyristors, not be necessary auxiliary turn-off circuit. These types of inverters are known below name inverters with load commutation. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39511.html 04:00 PM Wednesday 31, 1969 This paper proposes to realize a general solution for the remote control of a MHEPS; This solution has implemented by the authors at MHEPS-Cerna which belong to Hidroelectrica Targu-Jiu. It is necessary to administrate efficiently the hydro-energetic resources, decrease the cost of the energy and increase the running security. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39530.html 04:00 PM Wednesday 31, 1969 Early detection of a fault or damage at power plants is crucial for their control and maneuvering. In this paper, the author proposes a practical design method useful in the supervising of the system in presence of process faults. The fault detection and isolation (FDI) problem is an inherently complex one. The immediate goals is to preserve the stability of process and, if is possible, to control the process in a slightly degraded manner. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39527.html 04:00 PM Wednesday 31, 1969 Hydro dams are very important economical and social structures that have a great impact on the population living in surrounding area. Surveillance of dam status consists of a complex process which involves data acquisition and analysis techniques, implying measurements from sensors and transducers and visual inspection. To enhance the visual inspection process made by experts, we propose a computer vision technique that will allow assessment and quantification of water infiltrations inside the dam wall, based on infrared and visible spectrum image analysis and data fusion techniques. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39523.html 04:00 PM Wednesday 31, 1969 In the SCADA system monitoring, control and over-limit alarm processes from the hydroelectric power plants cascade (on the Cris river) have been obtained a large amounts of historical data stored in a database. But in their preliminary form these data don't mean a performance management. Data mining techniques applied over historical acquired data are used to extract hidden management information directly from the SCADA system's database records. This paper presents a data mining framework for the historical data of an industrial measurement and control system and establishes a data mining flow. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39524.html 04:00 PM Wednesday 31, 1969 In each hydroelectric power station, one of the outstanding systems is the power channel, which provides water flow to the hydroelectric power generators. On this power channel, there are two or more special valves that can interrupt the flow in specials conditions. In this specific application, there are two butterfly valves and the two command systems, placed together into a special underground room, called "valve house". The function of the each system is to allow the water flow reach the generators by keeping the valves opened (0 - 5 degrees) and to avoid the overflow of the underground power station in some cases. These two systems are conected by electrical signals, in order to increase safety in use by detecting malfunctions and to close at least one valve. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39516.html 04:00 PM Wednesday 31, 1969 Based on the resources and capabilities of the implemented SCADA system of the hydroelectric plant this paper describes temperature monitoring techniques for collecting, archiving, and analysing the data required by the operator, as well as generates predefined reports for maintenance management. The hardware and software support of SCADA system offer the way to investigate the real-time functioning status of hydro power plant generating units and create a tool to identify the stress induced by electrical and thermal condition. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39529.html 04:00 PM Wednesday 31, 1969 The classical Thermal Loop Test up to national standards of prophylactic measurement for high voltage rotating machinery was improved by the intermediate of thermo-graphic inspection with a last generation of INFRARED THERMOVISION CAMERA. The method generates thermo-graphic maps by intermediate of a dedicated software of the internal cylindrical surface of the magnetic core of the rotating machinery. The thermo-graphic maps are generated in strictly identical condition at the start of the generator, as well as at the major planned outages after 5, 10, 15, 20 years of functioning. The proposed method of testing allowed the users to compare the thermo-graphic maps and to put in evidence the "thermal hot spots" (respectively the magnetically failures) and their evolution in time and gives the users the possibility to establish the moment of partial or complete replacement of the iron core. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39528.html 04:00 PM Wednesday 31, 1969 A new distributed approach for monitoring the voltage events (sags and overvoltage) in electric power system is proposed. The distributed monitoring system is implemented on a set of microcontrollers connected to personal computers that are linked through Internet. The microcontrollers endowed with voltage transducers implement information agents that communicate to a software multiagent-agent system when voltage events occur. The users of the power system can get information about events occurred during a period of time. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39508.html 04:00 PM Wednesday 31, 1969 Classic control systems based on continuous dimming present some difficulties to adjust their performances to the rapid changes in daylight. Therefore, fuzzy control could be a better solution. The paper analyzes the possibility to implement this new technique in daylighting control and presents the structure of a fuzzy controller proposed by authors; its operation rules and the influence on the imposed value of the illuminance level are also studied. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39502.html 04:00 PM Wednesday 31, 1969 A first-principle dynamical model of a Pressure Swing Adsorption (PSA) reactor for hydrogen extraction from a gaseous mixture is presented. Then, a model for a whole fourreactor PSA unit, including the related valves and ducts, is introduced: this employs the single-reactor model and a global fluid-dynamical description; sequence control and continuous control are designed and some simulation results are discussed. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39506.html 04:00 PM Wednesday 31, 1969 The paper proposes Takagi-Sugeno PI-fuzzy controllers (PI-FCs) dedicated to a class of integral plants. Two PI controllers are developed first by Virtual Reference Feedback Tuning to ensure the desired control system (CS) performance with respect to the reference input. Other two PI controllers are developed using the Extended Symmetrical Optimum method to ensure the desired maximum sensitivity equivalent to good CS performance with respect to the disturbance input. Then, accepting the approximate equivalence between the fuzzy controllers and the linear ones, a development method for the PI-FCs is suggested. Experimental results are included to illustrate the effectiveness of the development. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39489.html 04:00 PM Wednesday 31, 1969 The traditional approach to modelling complex power plants often leads to cumbersome, expensive and inefficient models. This paper is concerned with the development of a systematic, hierarchical and modular modelling procedure and advanced control system design for large power plants. The system component defined by a generic nonlinear dynamic structure is arranged in a hierarchical structure with the appropriate communication interface. The nonlinear dynamic model is then employed to produce steady-state models and linear models, which can be used to investigate the transient characteristics, stability behaviour and control requirements. Advanced control methods are then proposed to optimally implement a desired set point change whilst satisfying operational variable constraints. In common with many process control applications, it is not possible to move from one power plant operating condition to another instantaneously. Previous ad-hoc methods to automate the transition usually involve ramping the set point over some pre-determined time horizon and implicitly satisfying the operational and safety constraints. The design of optimal methods for the implementation of future set points trajectories is addressed here using the techniques of Model Based Predictive Control (MBPC) for large-scale systems. A generic unit of Combined Heat and Power (CHP) unit is employed as an example. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39495.html 04:00 PM Wednesday 31, 1969 In this paper, we consider the problem of bounded state feedback stabilization and observers design of a class of nonlinear discrete-time delay systems. From an appropriate Lyapunov function and judicious mathematical manipulations, we deduce a simple LMI conditions (that may be checked easily) to ensure asymptotic stability of both the state feedback and the observer. First, we provide an explicit bounded state feedback law that may seen as generalization of the existing results in the nonlinear field. On the other hand, we present a useful and systematic approach to design observers for discrete-time systems with unknown delay. To illustrate performances of the proposed approach, a numerical example is provided. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39526.html 04:00 PM Wednesday 31, 1969 This paper presents a project which uses software agents as means for more efficient monitoring, testing and diagnosis of a complex heterogeneous system - multiple hydroelectric power plants connected in a chain on a river. The agent system will be superimposed over the existing SCADA control and monitoring network and will increase performance, efficiency and stability in the existing system. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39537.html 04:00 PM Wednesday 31, 1969 Considering both wind power drawbacks and the well known benefits and advantages of hydropower, and taking into account a general rule that stated that the power of wind plant is a fraction (30%) of wind power turbine, we proposed a hybrid eolian-hydro system for large utility system as a fine solution that has an overall integrated capacity factor better than those on we could trust before (30%). We had introduced a new efficiency factor for a better dimensioning expression of losses on dump loads in alone standing wind power plant. Finally we look for the solution on national scale, where hydro power represents a small part, fewer than 10%, as in Romania. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39522.html 04:00 PM Wednesday 31, 1969 An important amount of the Electric Power Generation (EPG) company costs is given by the maintenance costs. The implementation of a SCADA system in the hydro-power plant enables the improvement of the maintenance, management and general control strategy. Based on the new and large possibilities of the SCADA-systems, the actual paper presents (in accord to the legal frame) the fundaments for the implementation of the Operational Management System (OMS) for the Hydro-electric Power Plant belonging to the general system of the Hydraulic Power Plant. The target of the OMS is to create a general Hydro-power Plant Dispatcher (HPD) for the whole chain of Hydroelectric Stations from the Somes-river (Ordean, 2005). The local Information Net of each Power Station (already in operation) is connected to the HPD in order to supervise the station operation, but also to control, directly through HPD, the equipment of the Hydro-electric station. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39521.html 04:00 PM Wednesday 31, 1969 The papers presents a high performance speed and position control system for separately-excited D.C. motor, which was designed and performed with a dedicated integrated circuits (L290, L291, L292), made by SGS-THOMSON Microelectronics Company. The L290, L291 and L292 together form a complete microprocessor-controlled (microcomputer chips) DC motor servo positioning system that is both fast and accurate with an adequate software. The papers presents a description of the system, detailed function descriptions of each device and application information. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39497.html 04:00 PM Wednesday 31, 1969 The paper deals with the simulation and implementation of AC-drives with synchronous and induction motors fed by a local distribution DC-line, which is supplied from an autonomous vector controlled synchronous generator. The main AC-grid is connected to DC-line the via ecological power electronic converters with bi-directional power flow, like the AC-drives and the generator. Solutions are proposed for sine-wave rectifying and inverting of the energy accomplishing grid-side unity power-factor with active power-filtering of the AC-grid- and motor-side currents for different transferred energy levels. The energy-efficiency of the drives is achieved by means of vector control structures. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39513.html 04:00 PM Wednesday 31, 1969 Electric arc furnaces (EAFs) are commonly used in steelmaking and in smelting of nonferrous metals. Usual EAFs work at power levels from 10MW to 100MW. The power level is directly correlated to production throughput, so it is important to control the EAF at the highest possible average power with a low variance to avoid breaker trips under current surge conditions. To obtain the electric arc, usually there are used three graphite electrodes. The power level depends by the positions of the electrodes. As a result, the realization of a competitive control system is very important because it led to reduction of the energy consumption, pollution, and increases the safety of the process. This paper presents some aspects concerning modeling of the electric arc, modeling of the EAF electrical system, modeling and adaptive control of EAF process - hydraulic control system of electrode position. Finally, a simulation application is presented. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39514.html 04:00 PM Wednesday 31, 1969 Evolution and large scale spreading of the computational techniques allowed the design and realization of some acquisition, processing, storing and sending data taken from the process equipments to a superior level - dispatcher. In this way, it is presented a data acquisition equipment for energetic measures which is incorporated in a dispatching system aiming the monitoring and storing of electrical measures which are taken from electrical cells which compose the supervised electrical station. There is shown the system architecture underlining the taken signals, transducers used and the component elements of the system: Local data acquisition equipments (LDAqE), Local data acquisition equipments synchronization subsystem, Data communication subsystem and Processing, storing and data displaying subsystem. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39538.html 04:00 PM Wednesday 31, 1969 Our aim is to present the necessity and the objectives taken into account in the development of an ON LINE expert system, with free access, for the eolian sites designing process. The expert system is based on a set of rules and metric relations, and also on a Romanian patent. By eolian site design, we assume: 1. approximation of average and annual eolian potential, using terrain data, and 2. offering a blueprint for eolian plant project. This blueprint contains: potential technical solution, recommended installed power, optimal pillar height, approximation of capital costs, data about the providers for eolian plants, etc. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/39492.html 04:00 PM Wednesday 31, 1969 The national power system operates interconnected with the UCTE in the conditions of the European electricity market. In order to meet the technical requirements of the UCTE standards and to be able to face the competition on the European electricity market, optimum operation modes of the national power network have to be achieved by means of a comprehensive control system and reliable equipment. On the occasion of the national power system rehabilitation, some state-of-the-art control systems have been implemented: Turbine Automatic Speed Controllers, generator AVRs, unit load controls etc., to control the main parameters of the national power system operation and to have the generation units qualified for providing system services. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif