If the primary currents of a current transformer is fixed, how can it generate spikes on its secondary which are 3-4 times full load current. Won't it violate equations of transformer action?. Any chance of noise is also ruled out becuase spikes are being produced consistently in only two phases...
For a current transformer, what it means if both insulation resistance and tan Delta are being reduced over a period. e.g. tan Delta reduced by 40% while insulation resistance reduced by 10 times
The red plots show current spikes by only Y and B phase CTs (neutral side). Rest CTs show nearly same currents as previous.https://files.engineering.com/getfile.aspx?folder=457bd658-7cea-4f7a-bfc6-9ca50ab23849&file=IMG_0028.jpeg
There are CTs mounted at its neutral side also and phase side also. Only neutral CTs are showing short pulse of high currents. Phase side there is a marginal increase.
I have one HV 3 phase star ungrounded induction motor. Sometimes there is a short duration of 5 milliseconds high magnitude currents recorded at its neutral side. The frequency of occurrence is random, sometimes even few days. How can a fault be of such type? Please suggest.
