Top Banner
24
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Load Duration Curve
Page 2: Load Duration Curve
Page 3: Load Duration Curve

- -Power system planning, operation and maintenance need Power system planning, operation and maintenance need to deal with load data, the load data could be recorded to deal with load data, the load data could be recorded in different ways, one of these methods is to record the in different ways, one of these methods is to record the daily peak load, the other way is to record the hourly daily peak load, the other way is to record the hourly

load data in which the total data for a yearload data in which the total data for a year. . - -The load curve is a graph showing the variation of load The load curve is a graph showing the variation of load

on the power station with respect to time, in which the on the power station with respect to time, in which the x-axis shows how many hours the load was equal or x-axis shows how many hours the load was equal or

greater than the load level shown in the y-axisgreater than the load level shown in the y-axis. . - -LDC is used in different studies, such as power system LDC is used in different studies, such as power system

planning, reliability study, energy pricing,etcplanning, reliability study, energy pricing,etc..

Load Duration CurveLoad Duration Curve

Main conceptMain concept::

Page 4: Load Duration Curve

Fig:1 Actual Load Duration CurveFig:1 Actual Load Duration Curve..

Page 5: Load Duration Curve

Fig:2 Theoretical Load Duration CurveFig:2 Theoretical Load Duration Curve..

Page 6: Load Duration Curve

Load Duration Curve is represented on different types Load Duration Curve is represented on different types respecting to time, such as respecting to time, such as::

Daily load curveDaily load curve::

Load variations during the day ( 24Hrs ), recorded either half-Load variations during the day ( 24Hrs ), recorded either half-hourly or hourlyhourly or hourly . .

Monthly load curveMonthly load curve::

Load variations during the month at different times of the dayLoad variations during the month at different times of the day..

Yearly load curveYearly load curve::

Load variations during the Year, this is derived from monthly Load variations during the Year, this is derived from monthly load curves of a particular yearload curves of a particular year..

Page 7: Load Duration Curve

Demand Factor ( Dem.F ):Demand Factor ( Dem.F ): It is the ratio of maximum demand to connected load. It is the ratio of maximum demand to connected load. It is usually less than 1It is usually less than 1..

MD : Maximum demand

Maximum Demand ( MD )Maximum Demand ( MD ):: The greatest demand of load at the power station during a given The greatest demand of load at the power station during a given

periodperiod . .The highest peak on the power station load curveThe highest peak on the power station load curve..

Average loadAverage load: :

This is the average of loads occurring on the power station in a This is the average of loads occurring on the power station in a given periodgiven period . .

There are many factor affecting on load estimation at power There are many factor affecting on load estimation at power station such asstation such as::

Page 8: Load Duration Curve

Fig:3 Load Duration CurveFig:3 Load Duration Curve..

Page 9: Load Duration Curve

Diversity Factor ( DF )Diversity Factor ( DF )::

The ratio of the sum of all individual maximum demands on The ratio of the sum of all individual maximum demands on the power station to the Maximum demand on the station. the power station to the Maximum demand on the station. Consumer maximum demands don't occur at the same Consumer maximum demands don't occur at the same time ,thus the maximum demand on power station will time ,thus the maximum demand on power station will always be less than the sum of individual demandsalways be less than the sum of individual demands..

High DF = Low MD = Low plant capacityHigh DF = Low MD = Low plant capacity

Diversity factor is usually less than one, probably equal 80%Diversity factor is usually less than one, probably equal 80%

Page 10: Load Duration Curve

Capacity FactorCapacity Factor::The capacity factor for a power plant is the ratio between average The capacity factor for a power plant is the ratio between average load and rated load for a period of time and can be expressed asload and rated load for a period of time and can be expressed as

μμcf =(100)Pal/Prlcf =(100)Pal/Prl              wherewhere

μμcf=Capacity factorcf=Capacity factor(%) (%) Pal= average load for power plant for a period (KW)Pal= average load for power plant for a period (KW)Prl=Rated capacity for the power plant (KW)Prl=Rated capacity for the power plant (KW)((

Load FactorLoad FactorLoad factor for a power plant is the ratio between average load and Load factor for a power plant is the ratio between average load and peak load and can be expressed aspeak load and can be expressed as

μμlf=(100)Pal/Ppllf=(100)Pal/Ppl              wherewhere

μμlf=Load factorlf=Load factor(%) (%) Ppl= Peak load for the power plant in the period (KW)(max load)Ppl= Peak load for the power plant in the period (KW)(max load)Combined cycle gas plant, about 60%Combined cycle gas plant, about 60%

Page 11: Load Duration Curve

Availability FactorAvailability Factor::The availability factor of a power plant is the amount of time that The availability factor of a power plant is the amount of time that it is able to produce electricity over a certain period, divided it is able to produce electricity over a certain period, divided

by the amount of the time in the periodby the amount of the time in the period . .The availability of a power plant varies greatly depending on the The availability of a power plant varies greatly depending on the type of fuel, the design of the plant and how the plant is type of fuel, the design of the plant and how the plant is operated. everything else being equal, plants that are run less operated. everything else being equal, plants that are run less frequently have higher availability factors because they frequently have higher availability factors because they

require less maintenancerequire less maintenance . .Most thermal power stations, such as coal, geothermal and Most thermal power stations, such as coal, geothermal and nuclear power plants, have availability factors between 70% nuclear power plants, have availability factors between 70%

and 90%and 90% . .

Page 12: Load Duration Curve

* The following figures showes the behavior of * The following figures showes the behavior of

load duration curve with a diffefent kinds of load duration curve with a diffefent kinds of

applications such as:applications such as:

- Industrial application - Industrial application

- Commertial aplication - Commertial aplication

- Residential application - Residential application

Page 13: Load Duration Curve

Fig.4: Load duration curve for industrial applicationFig.4: Load duration curve for industrial application

Page 14: Load Duration Curve

Fig.5: Load duration curve for commercial applicationFig.5: Load duration curve for commercial application

Page 15: Load Duration Curve

Fig.6: Load duration curve for residential applicationFig.6: Load duration curve for residential application

Page 16: Load Duration Curve
Page 17: Load Duration Curve

Case study from the Egyptian codeCase study from the Egyptian code . .

For Green AreaFor Green Area

22 KW for 100 mKW for 100 m²²

For Streets areaFor Streets area

22 KW for 100 mKW for 100 m²²

For Commercial and administrative areaFor Commercial and administrative area

1212 KW for 100 mKW for 100 m²²

For Residential areaFor Residential area

88 KW for 100 mKW for 100 m²²

Page 18: Load Duration Curve

for our Case Studyfor our Case Study::assume 450000 massume 450000 m²² Green area Green areaassume 50000 massume 50000 m²² Streets area Streets areaassume 150000 massume 150000 m²² Commercial and administrative area Commercial and administrative area

assume 350000 massume 350000 m²² Residential area Residential area

SoutionSoution for Green area load = 450000 * 0.02 = 8000 KWfor Green area load = 450000 * 0.02 = 8000 KWfor Streets area load = 50000 * 0.02 = 1000 KWfor Streets area load = 50000 * 0.02 = 1000 KW

for Commercial and administrative area Loadfor Commercial and administrative area Load= = 150000150000 * * 0.120.12 = = 1800018000 KWKW

for Residential area Load = 350000 * 0.08 = 28000 KWfor Residential area Load = 350000 * 0.08 = 28000 KWDiversity factor = 0.64Diversity factor = 0.64Total load =Total load = 56000*0.64 = 35840 KW56000*0.64 = 35840 KW

Page 19: Load Duration Curve

At least 15 - 20% of extra capacity for future At least 15 - 20% of extra capacity for future expansion should be allowed forexpansion should be allowed for..

Total loadTotal load = = 42 MW42 MW

**the load required from the power stationthe load required from the power station**

This load will be divided into three units one of them This load will be divided into three units one of them 18MW and anther two units each equal 12 MW and it 18MW and anther two units each equal 12 MW and it

will be another unit 18 MW (stand by)will be another unit 18 MW (stand by)

Page 20: Load Duration Curve

New trendsNew trends

In new application the calculation of load do not In new application the calculation of load do not depend on the type of area only but it depend depend on the type of area only but it depend on the demand of all things on the location on the demand of all things on the location such as in domestic application the load such as in domestic application the load calculation depend on demand of lighting, calculation depend on demand of lighting, refrigerator ,freezer ,AC ,washing machinerefrigerator ,freezer ,AC ,washing machine..

Page 21: Load Duration Curve

Fig.7: Load duration curve for domestic applicationFig.7: Load duration curve for domestic application

Page 22: Load Duration Curve

To determine the maximum diversified demand for a given To determine the maximum diversified demand for a given saturation level and appliance, the following steps are takensaturation level and appliance, the following steps are taken : :

11 - -Determine the total load of appliances by multiplying the total Determine the total load of appliances by multiplying the total number of customers by the percent saturationnumber of customers by the percent saturation

22 - -Read the corresponding diversified demand per customer from Read the corresponding diversified demand per customer from the curve, [Fig:7], for the given number of appliancesthe curve, [Fig:7], for the given number of appliances

33 - -Determine the maximum demand, multiplying the demand by Determine the maximum demand, multiplying the demand by found in step 2 by the total number of appliancesfound in step 2 by the total number of appliances

44 - -Finally, determine the contribution of that type of load to the Finally, determine the contribution of that type of load to the group maximum demand by multiplying the results value from group maximum demand by multiplying the results value from step 3 by corresponding hourly variation factor found from step 3 by corresponding hourly variation factor found from

figure 7figure 7 . .

Page 23: Load Duration Curve

Table 1 shows the demand in a typical domestic applicationTable 1 shows the demand in a typical domestic application..

Appliances Rated power (watt)

AC 500

Freezer 160

Fan 50

Refrigerator 68

TV 60

Video 10

Washing machine 1000

Cassette recorder 8

Lights 2

Vent. Fan 10

Page 24: Load Duration Curve