Recent content by apowerengr

You need to reconnect the internal connections for full transformer capacity. You could make the connections externally but with only half capacity available since you'd be only using half the winding. I've done a hundred of these myself - half day if you are short on coffee in the morning, a...

If the secondary isolation links were shorting the CT terminals and you connected a low-burden revenue meter the current would divide based on the ratio of impedances of the parallel paths. No way to know what percentage of the load the meter was registering unless you measure the impedance of...

excitation from the grid connection - min flow unit will be connected to a local distribution feeder operated by the same utility which owns the hydro plant.

We are looking at retrofitting a new minimum flow unit of 400kW into an existing hydro plant - in this situation would you use an induction or asynchronus generator and why?

The new IEEE C37.2 2008 would label it as DDR for dynamic disturbance recorder or DFR for digital fault recorder depending on its function

I'm not familiar with the Asbury reference, searched several IOU spec books and did not find it either. As for bonding H2 directly to X2 this was (and is) a common practice by utilities who used bolted connectors. Run your #6 or #4 CU from the primary neutral through the H2 bushing connector...

size the CT and ratio to handle the short circuit issue for protection. meter the transformer secondary for load data.

fault currents look too high to me based on the impedances you stated.

Your model still looks funny. 20 MVA at 14% on an infinite source at 7.2kV is only 11.45kA. Four of them in parallel is only 45.8kA. I'm guessing you don't have two fully-independent sources. How are you getting > 100kA?

MikeVA - from what I've seen switch platforms are required for system operating voltages greater than the insulating level provided by the rubber gloves used by the operator when operating the switch. In other words, if the operator has gloves adequate for the system voltage level switch ground...

Try electricalmanuals.net or WES service provides training and may sell maintenance manuals.

Your short circuit values don't make sense to me given the system description. I'm assuming you have 56kA at 480 volts and that the fan is connected to the 7200 volt bus? Closing the 7200 volt bus tie won't cause the 480 volt fault current level to double. What am I missing? Can you post a...

17 amp coil current for 3-5 cycles hardly overloads #14 wire and I would expect you have fuses (or provisions which may be slugged) on the trip, close and motor circuits which more closely protect the conductors in question. The #10 from the DC panel to the termination comparment is sized as...

Try Northwest Lineman's College.

Is this a neutral-to-earth (NEV) question?