Tests, checks and diagnostics of ship medium voltage transformers

Abstract

Object and purpose of research. The study deals with the diagnostic Issues of ship MV transformers from factory acceptance tests to harbor trials. The purpose is to analyse the requirements and advanced diagnostic tools for status monitoring of ship power transformers, as well as to overview the Issues of electrodynamic withstand checks on transformers. Materials and methods. Stages (operations) are considered that ship power transformers undergo from the stage of factory acceptance tests to harbor trials. Requirements of ship transformers are analyzed. Foreign and Russian tools to check and measure power transformer parameters in industry as well as requirements for electrodynamic withstand testing are compared. Main results. It is shown that in view of high operational risks associated with accidents and failures of onboard transformers it is not enough to check transformer characteristics after transportation or storage (prior to onboard installation) for ensuring their high reliability. Functional analysis of foreign and Russian diagnostic instruments is presented, and vectors for improvement of the Russian tools are defined for the interest of shipbuilding industry. It is shown that the electric withstand tests are particularly important when new designs and technologies are used where reliable verification is impossible neither through calculations nor through modeling, while large safety margins are economically not viable. Conclusion. If some power units in the electric propulsion system (EPS) fail, extra costs would be spent on docking the vessel, dismounting of good equipment and hull structures to remove out-of-order equipment. Regulatory documenttation does not specify the scope of EPS components’ checkup after transportation or storage. Technical measures to ensure reliability of EPS elements include diagnostics of EPS elements prior to their installation on board the ship and during commissioning trials. Diagnostic tools of foreign make have more functional capabilities as compared to Russian instruments. Choice of specific devices and decisions to go for extra costs to further develop the Russian instruments should be based on feasibility studies. New regulations are required for testing rectifier transformers for electrodynamic withstand at short-circuit fault, as well as development and modernization of regional inter-industry shock test facilities.