Methods for Prognosis and Optimization of Energy Plants Efficiency in Starting Step of Life Cycle

Abstract

The probability that an energy system will successfully enter into operation and perform the required function of the criteria within the allowed tolerances for a given period of time and given environmental conditions (working temperature, pressure, humidity, permissible vibrations, noise and shock, changes in operating parameters of labor, etc.) represents its effectiveness. The effectiveness indicator is characterized by a unit (unit parameter) or several effectiveness properties (complex parameter), such as: reliability (the ability of system to maintain continuous working ability within the limits of allowed deviations during the calendar period of time, quantified through indicators: probability of operation without cancellation, medium time in work, intensity of cancellation and cancellation rate), maintenance convenience (ability to prevent and detect cancellation and damage, to restore working ability and correctness through technical service and technical repairs, quantified through: probability of renewal for the given calendar period of time, medium recovery time and the intensity of renewal), durability (the system’s ability to maintain its working ability from the very beginning of its application or exploitation until the transition to limit states in which certain stop is possible in the realization of certain activities for technical service maintenance and repairs, defined through indicators: medium resource, gamma-percentage resource, medium expiration date, gamma-percentage life), stability (the system’s ability to continuously maintain hot reserves, storage and/or transport). Optimal management of complex technical systems must be based on the assessment and complex optimization of the reliability indicators, depending on how they are provided and the hierarchical level of detailing, as well as the current phase of the life cycle. For these reasons, the optimization process includes the basic structural, parametric and constructive solutions related to the technical system itself through the change of its most important characteristics: efficiency (mostly energy), maneuverability, reliability and economic effectiveness in general. The set of goals of optimization is concluded in the overall choice of reliability indicators and possible ways to secure them, and given the already established rules regarding the higher hierarchical level of the system. Creating effectiveness is closely related to the concrete energy system, its behavior at a certain time and the environment in which it works (the power system as a higher hierarchical system). For this realization, it is necessary to provide the appropriate backgrounds, first of all the database, then to define based on the function of the goal and the available database of the interconnection and the relationship between the individual elements of the system. Within this chapter, appropriate methods will be provided for prognosis and optimizing the effectiveness based on the quality of design, production and testing, assembly and trial release, exploitation, development of procedures for prognosis of the complex systems behavior based on the characteristics of certain constituent elements of the system and the possible impact of human factors and environment itself on the system. Starting from the initial stage of development, design and conquering the production of certain types of thermal energy equipment in the goal of fulfilling all requirements without limitations, if it is based on its purpose, a multivariate assembly is set up before the designer, with the need to optimize according to certain already adopted algorithms. The goal is to create such a facility that has a satisfactory structure in terms of reliability indicators, with minimal costs of maintenance during the projected working life. Defining the plant that best meets the set requirements related to reliability and the process of exploitation and maintenance itself must be the result of the implemented optimization process (in this case, on the basis of the selected minimum investment criterion). The sum consumption of all devices that ensure the normal operation of the thermal power plant is called own consumption. General consumption consists of all other devices that do not have a direct impact on the technological process at the plant. Preserving the continuity in supplying of own power consumption is essential for safe operation under normal operating conditions, in the case of short-term transitions, as well as in starting and normal stopping, it is particularly important in case of stopping in case of disorder or failure of the system. With the growing unit block strength, there is also the growth of unit power of electric motors with their own consumption, and therefore requirements related to the power supply. The basic problem is to achieve safe power supply in a variety of drive operation situations, with fewer short-circuit currents and the voltage drop when starting large synchronous motors. The solution is achieved by the proper choice of the transformer of own consumption and voltage level.