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mitreviper... 1) Overload protection can't differentiate whether the fault is within the generator's zone of protection, or outside it! 2) No! I suggest you use the Control.com Search feature. Their Archive contains numerous Protection topics! Regards, Phil Corso

I'm in total agreement with CSA... Response of your generator is very dependant on gen/system parameters, such as: o Generator characteristics. o Load characteristic. o Local power requirement. o Connection to grid: GSU Xfmr? OVH tranmission line? Please abide by CSA's comment to...

Raj... have you searched the Control.com Archives? Phil Corso

GSA... what is generator's voltage and MVA? Phil Corso

Pramod... 9) Have you asked your vendors what will be the effects of single phase-to-earth faults for each bus? 10) Have they provided regulation calculations? Phil Corso

Mohan... obviously it is harder to describe "load-angle" than it is to "observe" it. Following is a procedure that will produce the "load-angle. All one needs is a piece of chalk, and a stroboscope (even a fluorescent lamp will do.) 1) Use the chalk to mark a fixed-point on the generator...

Pramod... so far you have indicated at least two of the 3 windings are earthed. Furthermore, unless the tertiary-winding is also earthed, capacitive-coupling could elevate voltage of the entire tertiary-winding with respect to earth, so: 6) Is the tertiary wye-winding being used to carry...

Pramod... further to my earlier e-mail: 4) What did you mean by "and above?" Is the xfmr forced-air and/or forced-oil cooled? Phil Corso

Pramod... typically in a 3-winding transformer one winding is delta-connected to overcome problems. Questions are: 1) Is the transformer construction the core or shell-type? 2) Is the neutral of the primary winding (400kV)earthed? 3) If the answer to 2) is no, then is the 400kV circuit...

Mohan... in general there are several definitions of "load-angle" in use. The three typically used in Electrical Power Sytem vernacular are: Load-angle (1): The angle whose cosine is power-factor. Or, the arctan of the X to R ratio of a specific external impedance connected to an AC source...

KRA... following is a list, copied from thread #1026236772, that lists at least 15 factors that should have been considered: o Allowable voltage-drop for normal operating load. o Allowable voltage-drop for future operating load as determined by motor's Service Factor. o Allowable...

KRA... based on info you provided thus far, the answer to your 1st question is yes! Regards, Phil

Dyke... although the use of conventional cable is permitted in the USA, such is certainly not the case in countries following IEC Standards. It is true that conductor materials and insulation of conventional and IS cables are virtually the same! However experience gained the hard way...

Eusuf, the voltage-drop between the sending-end and receiving-end of any transmission line is based on four parameters: resistance; reactance; conductance; and capacitance. The first two are called the series-impedance of the line, while the last two yield the lines' shunt-admittance. The...

CSA... I agree with your admonition... tripping is necessary! However, I disagree with two of your views (one minor, the other more important): o While the Field-Breaker Device Number is "41" (at least in the US) the Loss-of-Excitation (LoE) protective relay function is Device Number "40."...

Ig... negative-sequence would show up as unbalanced stator currents! Thus far, none of the posters, including the originator, has observed the existence of such a condition. Regards, Phil Corso

Dilip... A large number of Posted Topics on this subject can be found in the Control List Archives. If you don't find a suitable answer, then send the following measurements o The three phase-to-phase voltages for each transformer, before with the tie-breaker open. o The three...

Adil... Roy reminded me of another point. If this motor is located in a Classified Area, and it is not explosion-proof, then its operation for longer than 1 hour in 10,000 is illegal! Phil Corso

Rahmad... if used solely for gen protection, then: o Age? o Type- airgap, horn, electrolytic, MOV. etc? o Rated voltage? o Noises emating from arrester? o Distance between gen and arrester location? o Evidence of severe arcing? o If encased, were tey...

Blackstone... Contact me off-list with your full name, company affiliation, title or job function, and your location, and I will send a description complete with schematics! Regards, Phil Corso (Cepsicon [at] aol [dot] com)