Diversity Factor & Voltage Drop- System Design

[mazen]

Dear Sir;

I have the following queries:

1. How do you select the Diversity Factor for a new system
to be designed, presuming I know the max load KVA?.

2. How do you calculate the voltage drop at the load side if the load is connected to the transformer through a cable?. My assumption that I have to calculate the voltage drop across the cable, i.e. IR, presuming that I know the load rated KVA or current and estimated load power factor. However, the transformer output voltage is not the same as its rated voltage, i.e. there should be a voltage drop also on the transformer (how to calculate?.). If you can send me an example, it will be helpful.

3. What should be the load power factors that I should consider in my design or study for the power requirements for a particular project, say a residential project?.

Regards,
Mazen [sig][/sig]

 

[jbartos]

Suggestion: The following references seem to be close to what your posting addresses:
References:
1. IEEE Std 241-1990 "IEEE Recommended Practice for Electric Power Systems in Commercial Buildings" (Gray Book)
2. ANSI/NFPA 70-1999 "National Electrical Code" (NEC)

1) Diversity Factor (DIF) is addressed in Reference 1 Par. 2.5.1 Estimation of Building Load. A crossreference is made to Reference 2, where one is supposed to use similar projects for the guidance.
2) This calculation is normally done by an electric software (SKM, Inc., ETAP by Oti, Inc., EDSA, etc.) because of many variables and accuracy. Voltage drops across the transformer should meet industry standards, Reference 2 Par. 3.2.4 "Voltage Profile Limits for a Regulated Distribution System." Also, Par. 3.6 "Calculation of Voltage Drops" addresses General Mathematical Formulas and Cable and Bus Voltage Drop Tables.
3) The mixed load power factor is generally 0.8 per unit. [sig][/sig]