We are building a new cement plant at a location where we already have an existing cement plant in service. The new cement plant will be fed from a 230kV to 4.16kV 25MVA transformer in a utility substation which we own. The existing plant if fed from the same size transformer. I just recieved the power study for out new plant which has a calculated load of 20.8MVA at 2893A.
Management has decided that they want to build a small grinding plant at this existing location as well, and want to try to service is off of the new transformer I mentioned above. The new grinding plant will only be about 2MVA which we have room on the transformer for, however I have come to find out that the bus on the secondary side of the main trasformer in the substation is only good for 3000A. Rather than replace this existing 3000A bus with 4000A bus or bus with some other larger capacity I was looking into what options are avalialbe.
One of the possible options I came across was article 220.87 which states that you can obtain a calculated load from an existing load. In a cement plant a lot of times equipment is grossly oversized as such that we will never see the 20.8MVA calculated full load mentioned above. This article in the NEC says that you have to have trended data for a 1yr period before you can determine this existing load. Because we are looking to add this new grinding plant before this 1yr timeframe I was looking for other options.
Is there a shorter timeframe that we can meter data for once the plant is up and running? Can we use our existing plant whcih is in service and very similar to determine the existing load for our new cement plant not yet in service? Trending data for our existing plant shows consumption of about 16MVA. I'd appreciate any help.
Management has decided that they want to build a small grinding plant at this existing location as well, and want to try to service is off of the new transformer I mentioned above. The new grinding plant will only be about 2MVA which we have room on the transformer for, however I have come to find out that the bus on the secondary side of the main trasformer in the substation is only good for 3000A. Rather than replace this existing 3000A bus with 4000A bus or bus with some other larger capacity I was looking into what options are avalialbe.
One of the possible options I came across was article 220.87 which states that you can obtain a calculated load from an existing load. In a cement plant a lot of times equipment is grossly oversized as such that we will never see the 20.8MVA calculated full load mentioned above. This article in the NEC says that you have to have trended data for a 1yr period before you can determine this existing load. Because we are looking to add this new grinding plant before this 1yr timeframe I was looking for other options.
Is there a shorter timeframe that we can meter data for once the plant is up and running? Can we use our existing plant whcih is in service and very similar to determine the existing load for our new cement plant not yet in service? Trending data for our existing plant shows consumption of about 16MVA. I'd appreciate any help.
