Montenegro: Analysis of water supply pipeline at the perucica hydroelectric power plant

7. June 2016. / SEE Energy News

The Perucica hydroelectric power plant comprises seven hydroelectric units with an installed capacity of 330 MW. It is the oldest large hydroelectric power plant in Montenegro operating since 1960.

Defect expansion along the bifurcated pipe structure, mainly in the base metal of the anchor, in 2012 caused the bifurcated pipe to rest on the anchor instead of the collar.

The biggest operating issue of the Perucica hydroelectric power plant is the structure of pipeline No. 3 and the load bearing capacity of the bifurcated pipe No. 1, according to Miodrag Arsic, Mladen Mladenovic, Zoran Savic, Darko Bajic and Simon Sedmak who presented their view in the joint paper at the 31st international conference Energetika 2015. Loads occurring in this area result in an increase in the level of damage to the base metal and welded joints on the component parts of the bifurcated pipe. This jeopardizes the structural integrity of the pipeline as a whole.

This paper presents non-destructive testing results in the base metal and welded joints of structural pipe parts (collar and anchor), as well as the results of the destructive tests on the basic materials of the anchor. Non-destructive testing included visual testing, magnetic particle and ultrasonic testing with identification of the chemical composition, tensile properties, impact energy and hardness.

The function of the collar located above the bifurcated pipe is to receive static and dynamic loads and displacements occurring due to non-stationary dynamic loads, while the anchor is used to strengthen and balance the bifurcated pipe body. In 2012, a significant defect expansion along the bifurcated pipe structure, mainly in the base metal anchor, caused the bifurcated pipe to rest on the anchor instead of the collar.

Based on the testing results, it was found that the main cause of damage to the structure of the bifurcated pipe No.1 on the pipeline No. 3 was the base material degradation of the anchor and welded joints between the collar and the anchor and between the anchor and the pipeline. As a result, the bifurcated pipe began to rest not on the collar as designed, but on the anchor which is unable to receive all loads occurring throughout operation.

The Perucica hydroelectric power plant comprises seven hydroelectric units with an installed capacity of 330 MW. It is the oldest large hydroelectric power plant in Montenegro operating since 1960. This high-pressure hydroelectric power plant has a system of 3,335 km long concrete tunnel, an intake reservoir with an expansion and spillway, and three steel pipelines with dual horizontal shafts Pelton turbines. Five turbines have a nominal capacity of 38 MW, while the capacity of the remaining two is 58.5 MW, transmits Serbia-energy.eu

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