Regarding the problem of secondary paralleling of transformers
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There are two sets of urea systems in our factory. The new urea is not equipped with a backup generator set. The backup power supply is pulled from the old urea power distribution room. The new urea transformer is 10/0.4KV (2500KVA) and the old urea is 6/0.4KV (2000KVA). Now the main and backup power supplies of the new urea are not interlocked. If the main and backup power supplies are mistakenly connected together, what will happen? This post was last edited by btlhrdb2008 on 2009-4-25 20:07 ]
It seems that the primary voltage of the two old and new systems is different. One primary voltage is 10kV, and the other primary voltage is 6kV. Fortunately, the two low-voltage outputs are the same voltage. If the phases are checked, it is okay to parallel the low-voltage sides. Several conditions for parallel operation are: 1． Transformer wiring group is the same ； 2. The transformation ratios of the transformers should be equal, and the maximum allowable error does not exceed ±0.5 ； 3． The impedance percentages of the transformers should be as equal as possible, and the maximum allowed error does not exceed ±10% ； 4． The capacity ratio of the transformer does not exceed 3: 1. All other conditions can be met, except for the second one. Because the primary voltages are inconsistent, the transformation ratios are not equal. All other conditions are met because the primary windings of parallel-operated transformers are connected to the same voltage. In the situation mentioned by the poster, as long as the primary voltage is used to prevent misoperation, there should be no problem if the secondary voltage is paralleled.