What is Demand Factor-Diversity Factor-Utilization Factor-Load Factor

DEMAND FACTOR-DIVERSITY FACTOR-UTILIZATION FACTOR-LOAD FACTOR

(1) DEMAND FACTOR (IN IEC, MAX.UTILIZATION FACTOR (KU)):

The word “demand” itself says the meaning of Demand Factor. The ratio of the maximum coincident demand of a system, or part of a system, to the total connected load of the system.
DEMAND FACTOR = MAXIMUM DEMAND / TOTAL CONNECTED LOAD
For example, an over sized motor 20 Kw drives a constant 15 Kw load whenever it is ON. The motor demand factor is then 15/20 =0.75= 75 %. * Demand Factor is express as a percentage (%) or in a ratio (less than 1).
DEMAND FACTOR IS ALWAYS < =1.
Demand Factor is always change with the time to time or hours to hours of use and it will not constant. * The connected load is always known so it will be easy to calculate the maximum demand if the demand factor for a certain supply is known at different time intervals and seasons. * The lower the demand factor, the less system capacity required to serve the connected load.
CALCULATION:
(1) A Residence Consumer has 10 No’s Lamp of 400 W but at the same time It is possible that only 9 No’s of Bulbs are used at the same time. Here Total Connected load is 10×40=400 W. Consumer maximum demand is 9×40=360 W. Demand Facto of this Load = 360/400 =0.9 or 90%. * (2) One Consumer have 10 lights at 60 Kw each in Kitchen, the load is 60 Kw x 10 = 600 KW. This will be true only if All lights are Turns ON the same time (Demand factor=100% or 1) * For this Consumer it is observed that only half of the lights being turned ON at a time so we can say that the demand factor is 0.5 (50%). The estimated load = 600 Kw X 0.5 = 300 Kw.
USE OF DEMAND FACTORS:
Feeder conductors should have sufficient Ampere Capacity to carry the load. The Ampere Capacity does not always be equal to the total of all loads on connected branch-circuits. * This factor must be applied to each individual load, with particular attention to electric motors, which are very rarely operated at full load. * As per National Electrical Code (NEC) demand factor may be applied to the total load. The demand factor permits a feeder ampearcity to be less than 100 percent of all the branch-circuit loads connected to it. * Demand factor can be applied to calculate the size of the sub-main which is feeding a Sub panel or a fixed load like a motor etc. If the panel have total load of 250 kVA , considering a Demand factor of 0.8, we can size the feeder cable for 250 x 0.8= 200 kVA. * Demand factors for buildings typically range between 50 and 80 % of the connected load. * In an industrial installation this factor may be estimated on an average at 0.75 for motors. * For incandescent-lighting loads, the factor always equals 1.

DEMAND FACTOR FOR INDUSTRIAL LOAD

Text Book of Design of Elect. Installation- Jain

Electrical Load

Demand Factor

1 No of Motor

Up to 10 No’s of Motor

0.75

Up to 20 No’s of Motor

0.65

Up to 30 No’s of Motor

0.6

Up to 40 No’s of Motor

0.5

Up to 50 No’s of Motor

0.4

DEMAND FACTOR

Text Book of Design of Elect. Installation- Jain

Utility

Demand Factor

Office ,School

0.4

Hospital

0.5

Air Port, Bank, Shops,

0.6

Restaurant, Factory,

0.7

Work Shop, Factory (24Hr Shift)

0.8

Arc Furnace

0.9

Compressor

0.5

Hand tools

0.4

Inductance Furnace

0.8

DEMAND FACTOR

Saudi Electricity Company Distribution Standard

Utility

Demand Factor

Residential

0.6

Commercial

0.7

Flats

0.7

Hotel

0.75

Mall

0.7

Restaurant

0.7

Office

0.7

School

0.8

Common Area in building

0.8

Public Facility

0.75

Street Light

0.9

Indoor Parking

0.8

Outdoor Parking

0.9

Park / Garden

0.8

Hospital

0.8

Workshops

0.6

Ware House

0.7

Farms

0.9

Fuel Station

0.7

Factories

0.9

DEMAND FACTOR

Text Book of Principal of Power System-V.K.Mehta

Utility

Demand Factor

Residence Load (<0.25 KW)

Residence Load (<0.5 KW)

0.6

Residence Load (>0.1 KW)

0.5

Restaurant

0.7

Theatre

0.6

Hotel

0.5

School

0.55

Small Industry

0.6

Store

0.7

Motor Load (up to 10HP)

0.75

Motor Load (10HP to 20HP)

0.65

Motor Load (20HP to 100HP)

0.55

Motor Load (Above 100HP)

0.50

(2) DIVERSITY FACTOR:

Diversity Factor is ratio of the sum of the individual maximum demands of the various sub circuit of a system to the maximum demand of the whole system.
DIVERSITY FACTOR = SUM OF INDIVIDUAL MAXIMUM DEMANDS / MAXIMUM DEMAND OF THE SYSTEM.
Diversity Factor = Installed load / Running load.
THE DIVERSITY FACTOR IS ALWAYS >= 1.
Diversity Factor is always >1 because sum of individual max. Demands >Max. Demand. * In other terms, Diversity Factor (0 to 100%) is a fraction of Total Load that is particular item contributed to peak demand. 70% diversity means that the device operates at its nominal or maximum load level 70% of the time that it is connected and turned ON. * It is expressed as a percentage (%) or a r…