Facility Requirement Analysis of an UHV Transformer’s Short-circuit Test

Abstract

As the global energy problem becomes more and more severe, the ultra-high voltage (UHV) AC transmission technology will get a large number of applications. The UHV transformer, as one of the important equipments of the transmission system, its quality and reliability is directly related to the safe and stable operation of power system. At present, the normal performance of the UHV transformer is available by test method, except the ability to withstand short circuit need have the aid of calculation and simulation. Based on transformer short-circuit test requirements, the UHV transformer's maximum test ability of Changzhou Inspection & Testing Center for Electrical Equipment and the facility requirement of the commercial UHV transformer's short-circuit test are analyzed respectively in this paper. Introduction With the increase of energy demand, the scale of power system is more and more large. Because of large transport capacity, long transmission distance, low line loss, less occupation of land etc, the ultra-high voltage (UHV) AC transmission technology gains more favor in the field of large capacity power transmission over a long distance [1]. In China, there have been two 1000kV AC transmission lines into commercial operation, and there are three similar lines under construction [2, 3]. Predictably, the more severe situation of the global energy problem, the larger number of applications of the UHV AC transmission technology will be got. The UHV transformer, as one of the important equipments of the transmission system, its quality and reliability is directly related to the safe and stable operation of power system [4]. At present, the normal performance of the UHV transformer is available by test method, except the ability to withstand short circuit need have the aid of calculation and simulation [5, 6]. Therefore, Based on transformer short-circuit test requirements, the UHV transformer's maximum test ability of Changzhou Inspection & Testing Center for Electrical Equipment and the facility requirement of the commercial UHV transformer's short-circuit test are analyzed respectively in this paper. Requirement of the Transformer’s Short-circuit Test For the UHV transformer short-circuit test, the test ability mainly decided by two factors: One is the total impedance of test loop, namely under the test voltage, whether it has the output current , which is the《 IEC 60076.5 Power transformers Part 5: the Ability to withstand short circuit current》required, the other is the working ability of the test equipment itself, to test of the 1000kV transformer, it need to increase the working voltage and the insulation level of the testing transformer. According to IEC60076.5 rules, the short-circuit test of single-phase transformer satisfies the following equation [7]: International Conference on Intelligent Systems Research and Mechatronics Engineering (ISRME 2015) © 2015. The authors Published by Atlantis Press 524 2 s s s s U U Z S I = = (1) 2 k r t r U U Z S ⋅ = (2)