Development Of The Device For The 10kV Distribution Transformer Real-time Condition Monitoring

As distribution transformer is located in the end of power grid where is connected to power consumer directly,it becomes one kind of the most important electric equipments in the power system.Distribution transformer has the characters of a considerable quantity,a widespread location and complicate environment near its location.Though distribution grid has been the weakest part of power system for a long time,most amount of distribution grid breakdowns are caused by distribution transformer fault.Usually there is a lot of potential fault hiding in transformers.If we can not find them out quickly,it may not only has a bad effect on the reliability of power system but also turn into severe breakdowns and lead to a big loss.But nowadays distribution transformer monitoring is still in the method of manually test.So it is very necessary to monitor distribution transformers on-line.Most of transformer faults are the winding faults.So the paper researched on the relationship between the winding parameters and the winding faults.And then decided to make a on-line monitoring of transformer in the method of calculating and analyzing transformer parameters.The paper introduced the way to make a mathematical transformer model and then used LSE to estimate transformer parameters dynamically.Finally the paper made a simulation model to prove the validity of the method in Matlab/Simulink.Short-circuit resistance is an important parameter of transformer.So the paper decided to use the(38)-equivalent circuit and phasor method to calculate short-circuit resistance and put forward an idea of analyzing the electrical quantities in the method of adaptive notch filter in order to calculate the winding parameters.At last the paper made a simulation model which showed the validity of the method raised by the paper.The main reason of the current situation of distribution transformer on-line monitoring isbecause that traditional transducer is too huge and heavy for the installation on the distribution transformer.The paper introduced the current transducer based on the Rogowski coins and continued to develop it by adding the function of measuring range switching to enhance the accuracy of the transducer.In the end,the paper made experiments to prove the validity of the methods raised before and fulfill the function of transformer online monitoring.