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Hi All, We are going to have coupling Transformer for Static var generator and the Voltage Ratio is 220/33 kV. I have come across OEM GTP HV -LV Impedance is around 25% , is any specific reason for SVG application Impedance should be Greater than 25%. what will be the difference in construction...

Hi Kribanada and beyond86, Thanks for your feedback we are suspecting problem in the isolator side of the transformer bay no problem in the CT circuit, Because after trials of isolator open/close problem is shifting to other phase which seeing less current before it was not. In the offline we...

Hi All, I have attached screen shot of Transformer inrush current during energization, we suspect this is due to some problem in the primary circuit and checking the possibilities. Sometimes transformer gets energized without any unbalance in current among phases. Due to unbalance in current...

Thanks all for your valuable feedback and prc sir for your explanation in simple words.

Hi all, I am going through a specification in which mentioned tertiary winding may be provided if it is a five limb construction and trans former vector group is YNyn0, if tertiary not considered what are the consequences for the system.

Thanks David for your response , how the timer settings are applied during the relay testing and importance of the same, I will read and try to understand. Thanks crshears for your response.

Can anybody explain power swing blocking function in a simple manner than mentioned in the manual, for example GE Relay D60.

Hi Raghu, what should be the fault current considered for the CT sizing ie system design fault current or max fault current seen by the CT.

Sir my question is To calculate EMF developed across a Line protection PS core CT for Zone-01 faults, Normally in the case of 5P20 we will calculate EMF developed is ALF X Burden/Rated Secondary current but here we are not using Rct or burden mentioned in the CT is inclusive of internal CT...

Dear All, While calculating EMF developed across the CT secondary during fault for a through fault current , we have to consider CT internal resistance along with the connected burden or only R lead and Relay coil to be considered.

Hi dpc I have some queries , Erath fault protection will operate on Fundamental component, During energization high harmonic content will be there. In our system also many Ungrounded star winding transformer are in service with only source transformer star neutral grounded. Earth Fault...

Thank you all for your valuable feedback.

IEEE 242

Hi, I had a requirement from end user to have a coordination time interval between two relays to be 100 ms because of numerical relays and fast tripping breakers.As per IEEE guidelines minimum coordination interval of 0.12 seconds to be considered between numerical relays excluding breaker...

I recently come across the value of X0 Ohms/KM is less than the value of X1 Ohms/KM,is it right or wrong.