Auto transformer tap changing
Dear Friends,
would like to share an interesting experience during my work as a commissioning Er. We were working in a 380 kV/132/13.8 kV transmission SS. The transformers were Areva make Autotransformers 502 MVA each ( 2 nos). The first charging of the transformer...
Thanks Scotty, I am sure with about one month at a design desk, I will pick up the overall job requirements. Well I will keep trying. Is there any certification course that can be done to prove to recruiting firms that you can do the job ?
The same electrical phenomenon can be explained based on Circuit Theory or Field Theory ( may be some more theory I am not aware of) giving rise to different explanations.
Dear friends,
During my nine years in electrical engineering field, I have worked in various roles like Maintenance Engineer, Project site Engineer and at present Testing and commissioning Engineer for Extra High voltage Transmission substations. At present, I have a family and my job role...
Thanks ! Even the 270 degree stuff was not one of my own making but rather it was conveyed during a training session by an old Engineer ( well past his 60's) some 3 years back.
I used to be a lazy bone during my college days -:(. With the passing of time, I am sure I will become a better Engineer.
Well, it is nice to know the various view points by industry experts. Myself, I am only 9 years into Electrical engineering work. Some two weeks back , I was going through the "Performance and design of AC machines" by MG Say, for certain information on transformers and I was forced to go back...
Thanks to all experts who gave their precious time for answering my basic query. After going through the various comments, what I understand is as follows:
1) Since i=C*du/dt, there is a current as soon as voltage starts to change. The fact that capacitor acts as an initial short for applied...
Dear all,
Kindly correct my observations if wrong :
1) In any circuit, the current is produced by means of application of a voltage. Thus voltage is the cause and current the effect.
2) The phasors representing the various currents and voltage show the phase relationship between the components...
What is the significance of the first pole to clear factor mentioned in a Circuit breaker name plate details ? Does it have any impact on the ability of the CB to make / break capacitive currents ? thanks in advance .
Dear friends,
We have a 502 MVA Auto Tr. tertiary( 13.8 kV delta) grounded through a zig-zag tr. The CTs for phase O/C protection of the grounding Tr. have their secondaries connected in delta. The relay used for above protection is Siemens 7SJ611. I would like to know as to what should be the...
Thanks Mr.Kiribanda,
My transformer 132 kv /13.8 kV neutral is grounded through an NER (800 A/ 10 ohms). Max feeder load current is 300 A. Ph O/C Pick up is 400 A, highset of 2400 A. As per my company guidelines, SEF setting is having time delay of 5 sec. If there is a ground fault then before...
Hi everybody,
I have this query regarding Sensitive Earth fault protection. Normally in our installation, the feeder protection for 13.8 kv (distribution) is O/C , E/f ( 50/51,50N,51 N) provided in one relay and Sensitive earth fault (51G) provided in another relay. Presently my contractor has...
I have a small doubt about the NER. The NER available at my project installation has a ground connected to the resistor terminal. Also another ground is connected to the body of the NER. Is it correct to earth the body of the NER ? My concern is about a possible condition when the insulation of...