What are disadvantages of low power factor
?

Question

Abdulrahman saeed · Answer

The disadvantages are :1 . large KVA rating of equipment

2 . Greater conductor size

3 . large copper losses

4 . poor voltage regulation

5 .Reduced handling capacity of system

martin lison vadukoot varkey · Answer

Power in a Three Phase AC Circuit = P = √3 V x I CosФ And Current in a Three Phase AC Circuits = I = P / (3 V x CosФ) I ∝1 /CosФ….… (1) Also, Power in a Single Phase AC Circuits = P = V x I CosФ And Current in a Three phase AC Circuits = I = P / (V x CosФ) I ∝ 1/CosФ……… (2) It is clear from both equations (1) an (2) that Current “I” is inversely proportional to CosФ i.e. Power Factor. In other words, When Power Factor increases, Current Decreases, and when Power Factor decreases, Current Increases. Now, In case of Low Power Factor, Current will be increased, and this high current will cause to the following disadvantages. 1.) Large Line Losses (Copper Losses): We know that Line Losses is directly proportional to the squire of Current “I2” Power Loss = I2xR i.e., the larger the current, the greater the line losses i.e. I>>Line Losses In other words, Power Loss = I2xR = 1/CosФ2 ….. Refer to Equation “I ∝ 1/CosФ”….… (1) Thus, if Power factor = 0.8, then losses on this power factor =1/CosФ2 = 1/ 0.82 = 1.56 times will be greater than losses on Unity power factor. 2.) Large kVA rating and Size of Electrical Equipments: As we know that almost all Electrical Machinery (Transformer, Alternator, Switchgears etc) rated in kVA. But, it is clear from the following formula that Power factor is inversely proportional to the kVA i.e. CosФ = kW / kVA Therefore, The Lower the Power factor, the larger the kVA rating of Machines also, the larger the kVA rating of Machines, The larger the Size of Machines and The Larger the size of Machines, The Larger the Cost of machines. 3.) Greater Conductor Size and Cost: In case of low power factor, current will be increased, thus, to transmit this high current, we need the larger size of conductor. Also, the cost of large size of conductor will be increased. 4.) Poor Voltage Regulation and Large Voltage Drop: Voltage Drop = V = IZ. Now in case of Low Power factor, Current will be increased. So the Larger the current, the Larger the Voltage Drop. Also Voltage Regulation = V.R = (VNo Load – VFull Load)/ VFull Load In case of Low Power Factor (lagging Power factor) there would be large voltage drop which cause low voltage regulation. Therefore, keeping Voltage drop in the particular limit, we need to install Extra regulation equipments i.e. Voltage regulators. 5.) Low Efficiency: In case of low Power Factor, there would be large voltage drop and large line losses and this will cause the system or equipments efficiency too low. For instant, due to low power factor, there would be large line losses; therefore, alternator needs high excitation, thus, generation efficiency would be low. 6.) Penalty from Electric Power Supply Company on Low Power factorElectrical Power supply Company imposes a penalty of power factor below 0.95 lagging in Electric power bill. So you must improve Pf above 0.95.

chelliboina naresh kumar · Answer

Higher current is required by the equipment, due to which the economic cost of the equipment is increased. At low power factor, the current is high which gives rise to high copper losses in the system and therefore the efficiency of the system is reduced.

Quazi Rizwan · Answer

Poor/Low power factor means more line loss and low transmission efficiency, more Capital Investment, ,loss of generating capacity, poor voltage regulation and greater Conductor size required, more reactive power consumption. Low lagging power factor causes a large voltage drop,hence extra regulation equipment is required to keep voltage drop within prescribed limits.

subhash UPDA REGISTERED · Answer

low power factor load impact comes on generation, transmission and in brief it makes uneconomical power generation and transmission.

Actually

Low power factor load

to supply that load with full performance current have to increase in predominant manner

P=IV*pf

i=P/(V*pf) (since voltage and power of load constant)

i of stator have to increase, line current also increase to supply same load of low power factor

Bala Murugan · Answer

Line losses are 1.57 times unity power factor

Larger generators and transformers required

Low lagging power factor causes a large voltage drop,hence extra regulation equipment is required to keep voltage drop within prescribed limits.

Greater Conductor size -To transmit or distribute a fixed amount of power at fixed voltage,the conductors will have to carry more current at low power factor.This requires a large conductor size.

mohamed amine zouaghi · Answer

Poor power factor means more line loss and low transmission efficiency, more Capital Investment,large KVA rating of equipment – larger size and expensive,loss of generating capacity, poor voltage regulation and greater Conductor size required.

MOHAMED KAMEL ELSAKHAWY · Answer

Power factor is inversely proportional to the Current Consumed so if the power factor is low then the current consumed for the loads will become higher and the consequences of that on the cost mainly and the strength of power network. while high KVA Rating will lead to the resize the equipment rating.

Mhadheb dami · Answer

mauvaise facteur de puissance provoque un augmentation de energie reactive donc augmeentation de courant reatif donc un echauffement des cables avec une perte d'argent

Nahamuthuraman Douraradja · Answer

1) Effect on Transmission lines -Greater conductor size

2) Effect on Generators, Transformers

3) High losses in power system

4) High Voltage drops -poor voltage regulation

مستخدم محذوف‎ · Answer

case of low Power Factor, there would be large voltage drop and large line losses and this will cause the system or equipments efficiency too low, also there would be large line losses; therefore, alternator needs high excitation, thus, generation efficiency would be low

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What are disadvantages of low power factor ?

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