Related to electric energy metering
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This post was last edited by championsan on 2022-8-18 at 12:20. Our factory has 10KV switchgear used to supply power to external units, and there are no meters on the side of those 10KV switchgear. There is an electricity meter on the low-voltage 400V outlet cabinet at the external facility. I would like to ask my factory about the method used by other companies to calculate electricity consumption: 1. Reactive power + active power as shown on the existing electricity meter; 2. Iron loss + copper loss of the transformer; 3. Line losses from the 10kV switchgear to the 10kV transformer (estimated). Is it the sum of these three items?
Hey sea friend, your method of estimation isn’t reliable at all! Although the relevant loads and various losses have been taken into account to a certain extent (it is still necessary to check whether there are any other directly powered loads on the 10KV bus of the external power supply users), it is not possible to obtain accurate figures! For this type of external power supply, the first thing to consider is installing a meter for measuring electricity consumption. It’s very simple to add a meter to such a distribution cabinet; then why wasn’t a metering function included when planning for external power supply in the first place? It is recommended that the original poster add it as soon as possible! Additionally, the poster can check whether the originally installed distribution cabinet is equipped with a multifunctional meter. If so, they can verify whether it has a kilowatt-hour metering function. In that case, it generally should suffice for temporary metering purposes!
The situation is rather complex; the 10KV switchgear does not currently have the necessary conditions to install metering devices. I just want to ask whether my current method of estimation is comprehensive under these circumstances?
Dear sea friend, you might also carefully check whether the microcomputer-based protection system installed on your 10KV output cabinet has functions for displaying and measuring active power (or perhaps it has a kilowatt-hour display function). Typically, such feedline protection systems come equipped with such measurement functions, which allow for the calculation of the active power consumption of the output line; this method should be much more accurate than what you’ve mentioned!