Fundamental of Electrical Loads Chapter 7 Fundamental of Electrical Loads 4/17/2017 Prof. Magdi El-Saadawi

The Load Curve It gives the following information Variation of load during different hours of day Max. and Min. value s of daily load Average annual load of the station Information whether the installations is working efficiently or not 4/17/2017 Prof. Magdi El-Saadawi

4/17/2017 Prof. Magdi El-Saadawi

4/17/2017 Prof. Magdi El-Saadawi

شكل توضيحى لحمل حكومى المحور الرأسى يمثل الحمل بالكيلو وات المحور الأفقى يمثل الزمن بالساعات 4/17/2017 Prof. Magdi El-Saadawi

Difference between load curves of summer and winter 4/17/2017 Prof. Magdi El-Saadawi

4/17/2017 Prof. Magdi El-Saadawi

4/17/2017 Prof. Magdi El-Saadawi

4/17/2017 Prof. Magdi El-Saadawi

Load Duration Curve 4/17/2017 Prof. Magdi El-Saadawi

Load Duration Curve 4/17/2017 Prof. Magdi El-Saadawi

Load Curve and Load Duration Curve 4/17/2017 Prof. Magdi El-Saadawi

Average Demand: the ratio of kWh delivered by the station in a particular period divided by the hours in that period Load Factor Monthly L.F. = kWh supplied in a month Maximum demand * 24 * 30 Annual L.F. = kWh supplied in a year Maximum demand * 8760 4/17/2017 Prof. Magdi El-Saadawi

Diversity of Load يعنى أن الأحمال المختلفة لا تعمل فى فترة زمنية واحدة أو أن شركات الكهرباء تتبع سياسات تدفع إلى ذلك Diversity Factor the ratio of the sum of maximum demands of the individual category to the maximum demand of the power station 4/17/2017 Prof. Magdi El-Saadawi

Practical Example on Diversity Factor Solution 1: Transformer Size (Assuming Diversity Factor of 1.0) 2,000 + 1,500 + 1,000 = 4,500 kVA Solution 2: Transformer Size (Assume Diversity Factor of 1.2) Choose 3,750 kVA (4,500 kVA divided by 1.2 = 3,750 kVA) 4/17/2017 Prof. Magdi El-Saadawi

High or Low load factor value High or Low diversity factor value ? Which is better and why High or Low load factor value High or Low diversity factor value 4/17/2017 Prof. Magdi El-Saadawi

Indicates how best the plant capacity has been utilized Plant Factor Indicates how best the plant capacity has been utilized Station output in kWh kW1*h1 + kW2*h2 + kW3*h3 + ……. Capacity Factor is a value used to express the average percentage of full capacity used over a given period of time. Average demand on the Station Maximum Installed Capacity of the Station 4/17/2017 Prof. Magdi El-Saadawi

Connected Load Factor Average kWh Connected load * 8760 4/17/2017 Prof. Magdi El-Saadawi

Load Duration Curve 4/17/2017 Prof. Magdi El-Saadawi