Accident Analysis And Prevention About Paralleling Operation Transformers While Not-Meeting With The Parallel Condition

It’s occurred between parallelling transformers occasionally that the terminals’ voltage is unusual,not meeting with the parallel operation condition.In order to analyze and confirm the reason of it quickly, carry out the research on this subject.Using the transformers’ wiring principle diagram and the distribution rule of the magnetic flux in the three phase cores’ limps while applying the voltage from power source sides, estimates the relationship of voltage vector between the parallelling transformers’ terminals. It’s helpful to guide to analyze the reasons of not meeting with the parallel operation condition for technical engineers in installing site or in the manufacturing process rapidly,and to execute the prevention method during producing and installing process in advance as follows:1. It has studied the changes of the relationship of voltage vector between the parallelling transformers’terminals with normal relationship of voltage vector by using the transformer electric wiring diagram, the magnetic flux distribution diagram. It has estimated the changes of the relationship of voltage vector in details in kinds of accidents such as connection errors, and lacking one phase in power source sides or output sides,and not the same relationship of voltage vector between the parallelling transformers. And estimated the relationship of voltage vector between the parallelling transformers’ terminals in sumarry in kinds of accidents such as the tap position not being the same between the parallelling transformers, and the wiring errors in transformer manufacturing process or the defined connection symbol identification errors in technical documents.2. It has analyzed the reasons that occurred and ef fected the parallel condition possibility in the course of manufacturing processes, inspection processes,product test,and product inspection,and provide the corresponding preventive methods.3. It has analyzed the reasons that occurred and effected the parallel condition possibility in the course of taking on transformers in site,the main circuit and the second curcuits installing project of parallelling transformers,and provide the corresponding preventive methods.4. In this paper,it has analyzed the relationship of voltage vector between the parallelling transformers’terminals systematically while not meeting with the parallel condition, analyzed the inducing reasons in the course of manufacturing and installing project possibility,and provide the corresponding preventive methods. The result should be helpful to analyze the reasons of the accidents rapidly for transformer installers, maintenancers and the technical engineers of transformer manufactures,and taking corresponding preventive methods in advance.