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Shaheed... also see: http://www.control.com/thread/1026237476 Regards, Phil Corso

Marius... slip-frequency only "changes" if the machine has lost excitation and it then operates as an induction-generator! In fact its speed increases with respect to grid-frequency. Shaft-torque also increases! For the case where it has commenced slipping its first pole, then the...

Shaheed... PTs having their secondaries open-delta (connected) usually have their primary-windings connected phase-to-phase. Thus, they will not respond to earth-faults! Regards, Phil Corso

Mahesh... usually only two PT-derived voltages are compared by the Synchronizer unit: one on the Gen-side of the Gen's CB; the other on the Bus-side of the CB. Or, is the Bus-side voltage derived from a 3rd PT when back-feeding from the grid? Phil

I left out the thread that led to my original question! It is: www.control.com/thread/1307777525 Phil

Sorry I wasn't clearer. I meant during re-assembly? Phil

RAJA... what is the rotor's radial run-out value? Phil Corso

Gerald... for years distilled water has been used for washing high-voltage, live-line insulators. It is non-conductive, but must be applied as a mist when used to extinguish "electrical" fires! Regards, Phil Corso

Marius... Namantingan08 & ProcessValue, both presented some information on pole-slipping, I suggest you start with: http://www.control.com/thread/1267218529 Regards, Phil

CSA... only if Marius is actually referring to "slipping" a pole! Regards, Phil

Like Namatimangan08, I too believe it is a misprint, ant the correct term is "slip-fequency!" Phil Corso

Mahesh... how many PTs are used on each bus? Two or three? Regards, Phil Corso

Al, it is very difficult to provide exact solutions. However, because of the non-linearity of the load and because individual correction is costly, following are several ideas: 1) Arrange for testing of the system to uncover hidden flaws or weakness! 2) Include in your amelioration...

Al... I'm trying to develop a qualitative and not a quantitative anaysis, which leads me to ask the following question: Although the facility is about 33 years old, were they ever tested at the load for which they were originally designed? Phil Corso

Zahid... The answer, for the parameters you cited, is the fact that for the 50MW/5MVAr case the generator's output is 50.2MVA! And for the 50MW/25MVAr case the generator's output is 55.9MVA. Increased MVA means a corresponding 1ncrease in armature-current, thus higher generator-losses...

Pan... NO, it is not a stupid question! If you like, I can send you a copy of one of my SIS papers, "Probabilistic Risk Assessment of Equipment Safety Systems!" It does answer the Oxymoron, "Is Fail-Safe really Safe? Regards, Phil Corso

Sun... the information you asked for is enoute. Thank you for the courtesy of answering the simple questions I asked! In an earlier life, my electronics company, Trip-A-Larm Corp, supplied SCMs, RCMs, & TCMs, (Solenoid-, Relay- and Trip-Coil Monitors) for use in SIS Systems. In addition...

Al... one more question: 7) Are the 3x230kW generators synchronized on one bus, or are there 3 busses, coupled together thru inter-tie cables? Phil

Al... it is quite clear that the Generating Units are "swamped" by the (large?) non-linear VFD- load. As a starter answer the following questions: 1) What are the Nameplate ratings of the generators, i.e., kVA (or kW) and pf capacity? 2) Are all generators and their AVRs suppied by the...

Pan... No! There is no inrush in the sense that upon energization, the coil-current is multiples of the normal or holding-current. Even the initial rate-of-rise (di/dt) or slope of the coil-current is somewhat subdued! If you want a "picture" of the complete current waveform, contact me...