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The load on an installation is 600 kW, 0.8 lagging p.f. which works for 3000 hours per annum. The tariff is Rs. 100 per KVA plus 20 Paise per kWh. If the power factor is improved to 0.9 lagging by means of loss of free capacitors costing Rs. 60 per kVAR, calculate the annual cost saving (in Rupees). Allow 10% per annum for interest and depreciation on capacitors.
    Correct answer is between '7300,7500'. Can you explain this answer?
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    The load on an installation is 600 kW, 0.8 lagging p.f. which works fo...
    D = 600 kW
    Cosϕ1 = 0.8
    Cosϕ2 = 0.9
    Loading KVAR taken by the capacitors.
    = P (tanϕ1 – tanϕ2)
    = 600 (tan (cos-1(0.8)) – tan (cos-1 (0.9)))
    = 159.41 KVAR
    Annual cost before p.f. correction
    Maximum KVA demand = 600/0.8=750
    KVA demand charges = 750 × 100 = 75,000
    Units consumed per annum = 600 × 3000 = 1800000 kWh
    Energy charges per year = 0.2 × 1800000 = 360000
    Total annual cost = 75000 + 360000 = 435000
    Annual cost after p.f. correction
    Maximum KVA demand =600/0.9 = 666.67
    KVA demand charges = 666.67 × 100 = 66, 667
    Energy charges = 360000
    Capital cost of capacitors = 60 × 159.41 = 9564.6
    Annual interest and depreciation = 0.1 × 9564.6 = 956.46
    Total annual cost = 66667 + 360000 + 956.46 = 427623. 46
    Annual saving = 435000 – 427623.46 = 7376.54
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    The load on an installation is 600 kW, 0.8 lagging p.f. which works fo...
    Given:
    Load = 600 kW
    Power factor = 0.8 lagging
    Working hours = 3000 hours per annum
    Tariff = Rs. 100 per KVA + 20 Paise per kWh
    Capacitor cost = Rs. 60 per kVAR
    Interest and depreciation = 10% per annum

    To find:
    Annual cost saving after improving the power factor to 0.9 lagging by means of loss of free capacitors

    Solution:
    1. Calculation of KVA:
    Apparent power (S) = Real power (P) / Power factor (PF)
    S = 600 / 0.8 = 750 kVA

    2. Calculation of active power:
    Active power (P) = Real power (P) x Power factor (PF)
    P = 600 x 0.8 = 480 kW

    3. Calculation of reactive power:
    Reactive power (Q) = √(Apparent power (S)^2 - Active power (P)^2)
    Q = √(750^2 - 600^2) = 450 kVAR

    4. Calculation of present billing:
    KVA billing = 750 x Rs. 100 = Rs. 75,000
    Energy billing = 600 x 3000 x 20 / 100 = Rs. 3,60,000
    Total billing = Rs. 4,35,000

    5. Calculation of improved power factor:
    New apparent power (S) = Real power (P) / Improved power factor (PF)
    S = 600 / 0.9 = 666.67 kVA

    6. Calculation of new reactive power:
    New reactive power (Q) = √(New apparent power (S)^2 - Active power (P)^2)
    Q = √(666.67^2 - 600^2) = 240.83 kVAR

    7. Calculation of required capacitors:
    Capacitive kVAR required = Present reactive power (Q) - New reactive power (Q)
    Capacitive kVAR required = 450 - 240.83 = 209.17 kVAR

    8. Calculation of capacitor cost:
    Capacitor cost = Capacitive kVAR required x Rs. 60 per kVAR
    Capacitor cost = 209.17 x Rs. 60 = Rs. 12,550

    9. Calculation of interest and depreciation on capacitors:
    Interest and depreciation = Capacitor cost x 10% per annum
    Interest and depreciation = Rs. 12,550 x 10 / 100 = Rs. 1,255

    10. Calculation of new billing:
    KVA billing = 750 x Rs. 100 = Rs. 75,000
    Energy billing = 600 x 3000 x 20 / 100 = Rs. 3,60,000
    Total billing = Rs. 4,35,000

    11. Calculation of cost saving:
    Cost saving = Present billing - New billing - Interest and depreciation on capacitors
    Cost saving = Rs. 4,35,000 - Rs. 4,32,745 - Rs. 1,255 = Rs. 7,000

    Therefore, the annual cost saving after improving the power factor to 0.9 lagging by means of loss of free capacitors is Rs. 7,000 (approximately).
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    The load on an installation is 600 kW, 0.8 lagging p.f. which works for 3000 hours per annum. The tariff is Rs. 100 per KVA plus 20 Paise per kWh. If the power factor is improved to 0.9 lagging by means of loss of free capacitors costing Rs. 60 per kVAR, calculate the annual cost saving (in Rupees). Allow 10% per annum for interest and depreciation on capacitors.Correct answer is between '7300,7500'. Can you explain this answer?
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    The load on an installation is 600 kW, 0.8 lagging p.f. which works for 3000 hours per annum. The tariff is Rs. 100 per KVA plus 20 Paise per kWh. If the power factor is improved to 0.9 lagging by means of loss of free capacitors costing Rs. 60 per kVAR, calculate the annual cost saving (in Rupees). Allow 10% per annum for interest and depreciation on capacitors.Correct answer is between '7300,7500'. Can you explain this answer? for Electrical Engineering (EE) 2025 is part of Electrical Engineering (EE) preparation. The Question and answers have been prepared according to the Electrical Engineering (EE) exam syllabus. Information about The load on an installation is 600 kW, 0.8 lagging p.f. which works for 3000 hours per annum. The tariff is Rs. 100 per KVA plus 20 Paise per kWh. If the power factor is improved to 0.9 lagging by means of loss of free capacitors costing Rs. 60 per kVAR, calculate the annual cost saving (in Rupees). Allow 10% per annum for interest and depreciation on capacitors.Correct answer is between '7300,7500'. Can you explain this answer? covers all topics & solutions for Electrical Engineering (EE) 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The load on an installation is 600 kW, 0.8 lagging p.f. which works for 3000 hours per annum. The tariff is Rs. 100 per KVA plus 20 Paise per kWh. If the power factor is improved to 0.9 lagging by means of loss of free capacitors costing Rs. 60 per kVAR, calculate the annual cost saving (in Rupees). Allow 10% per annum for interest and depreciation on capacitors.Correct answer is between '7300,7500'. Can you explain this answer?.
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