PSI - Issue 48

Aleksandar Šotić et al. / Procedia Structural Integrity 48 (2023) 266 – 273 Šotić et al / Structural Integrity Procedia 00 (2023) 000 – 000

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H2. People are in the zone of the flood wave (violent) discharge of water from the HPP [A1] H3. Water quality endangers biocenosis [A2] H4. The available potential (within the boundary conditions) is not used for energy generation [A3, A5] H5. Water flows out of the system in uncontrolled manner [A3, A5] H6. The attitude towards the public is not appropriate [A4] System hazards are translated into corresponding Safety Requirements/Constraints, such as: SC1. Water discharge must be within a safe flow range, etc. As previously stated, this paper will not present a complete analysis, but only a demonstration of the methodology presenting a few specific details regarding the safety requirements SC1 and SC2. In the process of modeling the control and functional structure of the HPP Pirot, the elements of the high-level control structure are first identified. The technical documentation that is created for the needs of a HE system usually contains detailed descriptions of the designed, physical objects, while information about the functional behavior of the system is, at best, fragmentally scattered throughout the documentation, if it exists at all. The high-level functional control structure of the Pirot HPP system can be sketched based on publicly available data (Figure 4), while a more detailed representation of hierarchical levels (extension and decomposition) would require more information. The functional control structure of a socio-technical system, such as some HE system, can be developed using the basic assumptions of the hierarchy abstraction concept and the representation of the description of hierarchical levels from the works of Rasmussen et al. (1981, 1987). The basic building block of the entire functional control structure contains only the controller and the controlled process (Figure 2), and Figure 4 shows that various combinations are possible. One level, EPS - HPP Djerdap, controls both HPP Pirot and the Physical system, which has another controller, HPP Pirot.

Fig. 4. High level functional control structure of HPP Pirot.

Identification of (available/possible) control actions and feedbacks will focus only on the details that will be discussed in more detail in this paper: Control actions: OPERATOR > PHYSICAL SYSTEM: Valve/Closure ON (Reg)-OFF DJERDAP > OPERATOR: Production plan (energy - power - flow - aggregates) Feedback: PHYSICAL SYSTEM > OPERATOR: Measurements of level/flow/status of control elements OPERATOR > DJERDAP: Report on electricity production Next step is expansion and development of the high-level control structure. Adding details, developing or decomposition the physical system means separating, only at this point, the dam with reservoir, tunnels, pipelines, generators and control elements. Adding details, developing or decomposition the system operator means a representation of the manager of HPP Pirot, the crew of the control center and other operational personnel. The addition of higher hierarchical levels is carried out through the addition of professional and national levels. In this way, a socio-technical functional control structure was constructed so that it reflects the context or the big picture that determines the production of electricity in HPP Pirot.