For a single phase, 285MVA, generator step up transformer (which is part of a 3-phase bank), 23kV - 425kV, how do I calculate the transformer impedance at the minimum and maximum taps? The transformer has an off load tap changer on the high voltage winding.
Why are generator step up transformers sometimes specified with a high voltage winding rating higher than the nominal system voltage they are connected to? For example, a generator step up transformer connecting to a 400kV system is specified with a high voltage winding rating of 420kV.
My question pertains to a combined cycle power plant, one on one (gas turbine generator, steam turbine generator). The gas turbine generator will have a static frequency converter for starting. The plant will have black start capability, provided by diesel generator. Gas turbine generator output...
Can anyone tell me if there is a 'separation distance' requirement for separating underground ductbanks - for example, one bank with 34.5kV circuits and the other with 13.8kV circuits? How far apart do they have to be (minimum edge to edge dimension)?
I am sizing the feeder cable for a DC circuit from a 125VDC distribution panel to an inverter. The distribution panel is fed from a 125V battery. The inverter normally draws 5A and during a loss of AC power event, it draws 1200A for the first minute and 1A thereafter, for 2 hours ( the duty...
Is there a phase shift through a wye-wye, 500kV-230kV autotransformer with a 'buried' delta tertiary? Or is it a zero phase shift, as is the case with two-winding, wyw-wye transformers?
Thanks, in advance, for the help.
We are designing the grounding for roof mounted HVAC units for an industrial building. The roof will consist of precast concrete planks covered by rigid insulation and topped with a membrane. The equipment grounding cable will be bare copper. In the interest of minimizing the number of roof...
I have four (4) individual 120/240V, single phase, three-wire rated panelboards. However, the power source is 208/120, 3-phase, 4-wire. My loads require either 120V or are air conditioning units that are rated for both 208 and 240V. I think that I should be able to connect each of the above...
I need some help to determine the correct way to calculate the current in a 480V, single phase circuit, which services ten roadway lighting fixtures. The circuit is fed from a 2-pole (phases a-b), 480V, circuit breaker in a 480Y/277V, 3-phase, 4-wire panelboard. There are 10 - 480V rated...
