@article{
author = "Mladenović, M. and Arsić, Miodrag and Savić, Zoran and Bošnjak, Srđan and Gnjatović, Nebojša",
year = "2018",
abstract = "Hydro power plant ’Perućica’, which comprises 7 hydroelectric generating units, each with installed power of 330 MW, is the oldest hydro power plant in Montenegro and was put in service in 1960. This high pressure hydro power plant is a complex hydroenergetic system, which consists of a 3335 m long concrete tunnel, surge with a broadening and overflow and three steel pipelines with two-sided Pelton turbines with horizontal shafts installed.Five turbines have nominal power of 38 MW, while two have nominal power of 58,5 MW (307 MW overall).
The biggest problem at hydro power plant ’Perućica’ refers to the parent material and weld metal of the breeches pipe 1A located at pipeline III. Significantly lesser problems were detected at parent material and weld metal of breeches pipes 7B, 8A and 8B. Pipeline and breeches pipes were made of microalloyed steel ’Nioval 47’ (steel mill ’Jesenice’). Stresses that occur at pipelines in service during the process of execution of functional tasks (stationary and dynamic loads) and during the disturbed process of exploitation (non-stationary dynamic loads) cause severe damaging of parent material and weld metal at structural components of breeches pipes (collars and anchors), thus endangering the integrity of pipeline structure as a whole. Role of the collar, which enables the leaning of the breeches pipe on the foundation, is to receive static and dynamic loads (mean pressure of up to 61 bar in pipeline axis, specific load that occurs due to the quantity of water in the pipeline, action of the force of gravity) and displacements which happen due to non-stationary dynamic loads that occur at the pipeline, while the anchor strengthens and balances the mass of the breeches pipe.
In this paper the results of non-destructive tests carried out on parent material and weld metal (collar and anchor) of breeches pipes with designations 1A, 7A, 8A and 8B and results of destructive tests performed on parent material of the anchor are presented. Tests that were carried out include visual testing (VT), magnetic particle testing (MT) and ultrasonic testing (UT), while destructive tests included determination of chemical composition, tensile properties, impact energy and hardness. On the basis of results of test results it was determined that the main cause of occurrence of significant damages (degradation of parent material of the anchor and weld metal between the collar and anchor, as well as between the pipeline and the anchor) at the structure of the breeches pipe 1A of the pipeline III at the hydro power plant ’Perućica’ is the fact that the breeches pipe did not lean on the collar, as was predicted by design, but on the anchor which, due to the size of its cross-section, could not endure all loads that occur at the breeches pipe during service. Damages that occurred on parent material and weld metal of breeches pipes 7B, 8A and 8B are directly caused by flaws in welding technology and conditions of exploitation. Executed researches showed that degradation of parent material and weld metal does not influence the integrity of the pipeline III as a whole.",
journal = "Енергија, економија, екологија",
title = "Influence of degradation of parent-material and welded joints on the integrity of the breeches pipe located at pipeline iii of hydro power plant ‘Perućica’",
pages = "534-528",
volume = "1-2",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5011"
}
