Thank you for all your inputs. To have a clearer picture, this is a biogas plant, at present, the plant is exporting about 9MW of power. The 2MVA new generator will only have about 1MW of energy to export as it will provide supply to the plant own usage.
Can anyone suggest any good reading...
If a LRG is adopted for the 2MVA Generator, does it mean any external faults will choose this 2MVA Generator neutral as a return path (as this is a lower impedance path) rather than choosing the 14MVA Generator neutral which is with HRG path?
If we adopt a HRG, do we have to limit the current...
The smaller generator is located 300m away from the larger generator and will be connected to a different bus. the two buses will be linked with a 150sq.mm cable.
We have a 14MVA, 6.6kV generator generating power to the 33kV network through a 14MVA 6.6kV/33kV Transformer. This 14MVA Generator is grounded through a 762ohm grounding resistor to limit the fault current to 5A. Now we are going to add one unit of 2MVA generator to the 6.6kV system to run...
Thanks ScottyUK for pointing out. I am having the 16th Edition. Method 20 is for cables in enclosed trench. I will get the new edition to read further.
I am referring to the IEE Wiring Regulation. There is no web page I can find. Guess I can't scan and upload the Regulation here, can I?
Let me briefly describe the laying method in IEE Wiring Regulation.
The installation method is based on installation method 20 in Table 4A for cables laid in...
Thank you for all your replies.
Desertfox, for IEC standard a de-rating factor for different backfills is provided. But in IEE Wiring Regulation there is no de-rating factor provided. One can argue that the current rating given in IEE Wiring Regulation is based on an air filled trench, another...
My earlier thread 238-259943 was on Overheating of cables in trench. Now we end up having 21 x 1C, 630sqmm XLPE/PVC cables for the 2000kW 415V turbine generator system. The configuration of the cables laid flat spaced in trench is as follow, following IEE Wiring Regulation method 20...
I have heard about energizing the stator at reduced voltage to cause the winding to draw almost full rated current. My concern is whether the first failure of the stator windings already created some shorting between laminations and therefore lead to the second failure which occurred after two...
ScottyUK, I was just assigned to handle the testing part of the generator. But this is the second rewind job. The unit fail two months after the first rewinding job. This is why we are going to witness the tests before it is being transported back for installation. I have no record of the first...
Muthu and TurbineGen, thanks for the reply.
TurbineGen, could you please explain how a loop test is carried out. The stator was found badly burnt at end windings.
We are going to carry out the following tests on a 1800kVA 440V Generator: (stator windings were newly rewound)
1. Insulation Resistance and Polarization Index test
2. DC Resistance test of windings
3. No load output voltage with separate excitation and record excitation voltage and current.
4...
Thanks 7anoter4 for the information provided here.We are going to add one more cable to each phase to increase the current carrying capacity of the cables, meaning 6 cables per phase with three neutral cables. Instead of three layers of R,Y,B,N,B,Y,R configuration, is the following configuration...
I have checked the IEE regulation (which is available to me), there is no table to include soil thermal resistivity derating factor for cables. Whereas, from a manufacturer specification, with dry sand thermal resistivity of 2 K.m/W, the derating factor is 0.79 for 630sq.mm cables.
If I am...
