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Hi all I have a 5 winding transformer and in the software I am working there is no possibility to model 5 winding transformer. Hence I need a work out such that I can replace the 5 winding transformer with 2 three winding transformers. The name plate of the transformer is attached as a link...

Hi All I have few four winding transformers (data) however our simulation software DIgSILENT PowerFactory does not have four winding transformer. The data is given as an example for one transformer. 22kV/690V/690V/415V 1MVA/1MVA/500kVA 4.48%/5.13%/7.18%. I would like to seek an assistance in...

Hi I am looking for a help in four winding transformer . Does anybody have equivalent circuit of a four winding transformer. Recently I came across a four winding transformer with the following specification. 22kV/690V/690V/415V 1MVA/1MVA/500kVA 4.48%/5.13%/7.18%. I confirmed from the client...

Hi all As I was going through symmetrical components , I came across some question and hope that many of you could answer this. 1. In balanced network , only positive sequence current exists. 2. When there is earth fault in a phase , I assumed that zero sequence flows (considering star...

Hi Everybody Good Morning/Afternoon and evening While going through a number of electrical specification and design document , I used to come across words like WL1, WLD1, WBD1, WBD2 and WBD. Later on I understood that these words are derived based on some IEC standard. For example WLD1 -...

How does the ageing affect the core loss and cu loss of distribution transformer ? 1. because of short circuit and other high loading causes carbon particles to be formed and deteriorates the core properties ? (is it right ?) 2. Because of harmonics , What else Somewhere I read or heard...

Hi All We are preparing a maintenance schedule of Underground and overhead distribution system (11 kV) and we came across the cost of distribution system maintenace for budgetting purpose. Does anybody have an idea what is the tentative percentage of maintenace costs per transformer per km...

hi We are intending to replace all pole mounted transformer and over head distribution lines in a town with pad mounted transformer and underground cabling system. It will be done in a phase to phase basis . I mean like we build up underground cabling system and install new pad mounted...

Hi all Very Good Morning As far as I know PSSE and DIgSILENT two best software for load flow, short circuit , dynamic studies and protection coordination studies but having these two software is a question of big money and straight away jumping to this is not going to give in sight knowledge of...

which protection is more affected by CT saturation ? Any good literature with explanation ? Which is more sensitive to CT saturation ?

Hi all I just have a question in the mind as I read in a book that arrester common (neutral) and equipment neutral should not be connected together ? can anyone please give the reason why these two neutrals can not be connected together and what is the hazards during the lightning if they are...

Hi I was asked what I will do if there are a number of lightning strikes in a double circuit transmission line of 132 kV. How can this problem can be dealt with ? Could any body suggest the solution to this problem ?

Hi Everybody I just want to know when calculating the ruling span in transmission line we use the formula Ruling span=sqrt((sum of each span cube)/(total span)) between the dead end structure. I am confused with the term dean end structure. Can any one explain to me what is the meaning of dead...

Hi everybody Good morning Does any body have idea about the variation of transmission line resistance. What is the acceptable range of values of transmission line resistance. How can we measure the transmission line resistance ? Please suggest me if there is any literature regards simatic7

Hi I was given the responsibility of choosing turbine for a hydropower of 3 MW and we asked turbine manufacturer to supply the turbine with their preliminary specfication .They provided two turine with following spec option-1 option-2 Head 135...

hi I am a new engineer and want to know what is the precise difference between the AC directional over current relay (67) and ac non directional over current relay (51). In which case we have to use 67 and when to use 51. whether they can be used interchangebly or can not be used in that way...