HV Load Calculation

Addition mostly, with possibly some diversity factors when not all loads are active at once.

Yes please, Thank you for the addition

If it is an existing factory, you can do a Load Analysis for at least a week of two using a load analysis instrument (with data logger) from the mains utility incoming supply. From the stored data you can determine the factory's maximum loading, optimal loading, and minimal loading in Amps, kW, KVA, voltage variations, power factor, and THD. With these data, you can plan for the maximum rated RMU and main circuit breaker for the factory. With the maximum current loading data, you can determine the possible short circuit current, magnetic tripping current, temperature trip, and other parameters for the selection of your mains circuit breaker. The main breaker must be rated to the main switch board also, and with protection set to the factory maximum current loading. Also using this data you can select the best underground cable/XPLE cable for the run from RMU to your main circuit breaker.

If it is a new factory, you will have to look at the electric distribution design of the factory, and do appropriate load calculation/add up the entire load using standard load calculation practise in your country. The total load may be some percentage less to the factory's main switch board. Then you may select your RMU and circuit breaker based on your load calculations.

After you complete your work on the subject, you may get a consulting engineer to recheck the work so that all work s well. Otherwise, get a consulting engineer who will assist you with the job, and you will also learn from.

Thank you, this is very helpful.

I have started work on that already and will keep you posted.

Any other idea will also be welcome.

Yinkebo,

You're most welcome.

When you have completed load analysis of the particular factory, you may also consider using the data to determine a Power Factor Correction (PFC) Unit for the plant. As a rule of thumb, the KVA of the selected PFC Unit must not be more than 50% of the utility transformer KVA supplying the factory.