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I know Five winding transformers are not common. I wrote to few people however could not get any concrete answers. As cuky2000 suggested , I had looked those documents long before I posted this question in this forum. I was thinking of modelling the five winding transformer with two three...

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...

Till now i want to do just load flow, balance and unbalanced short circuit. Recently I came to know we can also model zero seq impendance my modifying similar three winding transformer zero seq circuit with additional winding. But still not 100% clear about this . If anybody has further...

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...

Thanks friends . I am now clear and as far as I understood , it is rightly pointed out by ijl , by adding the word may in the statement 3, I appreciate all the answer as they were short and precise. Thanks

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...

Thats true. My bachelor deg was electrical and masters in computer and after working in Unix for 7 years , again I started working as an electrical again so it is like that.

Thanks Zogzog for your complex answer to simple question and it was meant to be that and I wanted the way you did. I will find out the standard and check for that regards Simatic

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...

Our main intention is to replace the pole top transformer and pole so we eliminate poles so we have only underground cables so why we need riser pole . Dont we need arrester for switching transients ? regards

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 ?

I also read that if we put lightning arrester in one circuit (near the tower) of the line , the tripping rate in other ckt will also be reduced. so the possible solutions in total seemed to be 1. reduce the tower resistance and 2. we can put lightning arrester in one of the circuit.

Thanks Bill. It seems its a simple answer but to me its a great answer in a very clear and simplified way. Thnaks a lot. Simatic7

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...

yes in our country also we don't take care so much about lightning but here in Australia , I assumed they are more concerned with lightning than anything else. In the question , I was asked more about lightning only which I was least bothered . But it was a kind of time when I had to answer . I...