### Power Factor Correction Capacitors Sizing Calculations – Part Seven

Today, we will continue explaining Power Factor Correction Capacitors Sizing Calculations Steps in detail as in the previous article “we only listed the Power Factor Correction Capacitors Sizing Calculations Steps.

So, today we will continue explaining other steps for Power Factor Correction Capacitors Sizing Calculations For Existing Installations:

 4- Power Factor Correction Capacitors Sizing Calculations Steps

 Now, we are going to explain the Power Factor Correction Capacitors Sizing Calculations Steps for Different Cases of Installations: For Existing Installations, For New Designs.

 4.1 Power Factor Correction Capacitors Sizing Calculations Steps For Existing Installations

 the Power Factor Correction Capacitors Sizing Calculations Steps For Existing Installations include two phases as follows: Preliminary Evaluation Phase, Design Phase. Fig.1 shows the phases of Power Factor Correction Capacitors Sizing Calculations For Existing Installations. Fig.1

 First: Preliminary Evaluation Phase

 The preliminary evaluation is performed to determine if the application of power factor correction capacitors is likely to be economical or not. Fig.2 shows a typical flow chart for the preliminary evaluation process. Fig.2

 Step#3: Fill the Economic Screening Worksheet

 Example#1 for Economic Screening Worksheet A food processing facility fed at 480 V through a primary-metered 5 MVA transformer. The facility consists of three main processes which run independently. The kW level at each plant does not vary significantly. Thus, the overall kW level tends to be relatively constant for extended periods of time, with significant changes occurring only when a plant is started up or shut down. The typical peak demand at present is 1000 kW, which is much less than the 5 MVA transformer capacity. The system originally had considerably more compressors than it currently does. Fig.9 shows a simplified one-line diagram of the facility. The capacitor locations selected are shown on the diagram. Fig.9: Single Line Diagram for a Food Processing Facility Preliminary Evaluation The Economic Screening Worksheets for the preliminary evaluation of this site are filled out for this case as an example and shown in below. The information known about the plant before the detailed plant survey was that: The average power factor was about 78% and the desired power factor is 0.95. The typical demand was approximately 1000 kW. Assumed Cost/kvar for fixed capacitors \$30 per kvar. No harmonic study required. Billed demand 1240 KW and the actual demand 1020 KW from the bills. The billing schedule did not have a demand charge specifically identified, but an equivalent charge of approximately \$2.90 per kW was derived from one of the bills by computing the bill assuming the power factor was corrected. Monthly energy usage from the bill is 482900 KWH Cable Capacity Factor to be used as 0.2 The per unit resistance from the transformer nameplate is 0.00966. Note that the losses were evaluated at the marginal energy rate of \$0,007 per kWh, which is the lowest rate at the highest level of energy usage. This is the proper value for evaluating the effect of loss reduction because the losses are subtracted out at the margin. The used fixed capacitors will be studied for 3 years and 7% interest rate. Solution The solution by using our Economic Screening Worksheet is shown in below images: Results The worksheets indicate that a relatively simple fixed capacitor installation that costs approximately \$30 per kvar should be quite economical based on a three year evaluation period and interest rate 7%. So, we can proceed to the design phase and The simple payback period is predicted to be about 1.8 years.

In the next article, we will continue explaining other steps for Power Factor Correction Capacitors Sizing Calculations for Existing Installations. Please, keep following.

The previous and related articles are listed in below table:

 Subject Of Previous Article Article Glossary of Power Factor Correction Capacitors Types of Loads, The Power Triangle, What is a power factor? Types of power factor Why utilities charge a power factor penalty? Billing Structure. What causes low power factor? Bad impacts of low power factor, Benefits of Power Factor correction. How to make Power Factor Correction? Types of Power Factor Correction Capacitors Individual compensation Group compensation, Central compensation, Hybrid compensation. Summary for Power Factor Correction Capacitors Sizing Calculations Steps Step#1: Collect Monthly Billing Data Step#2: Make Some Preliminary Measurements For Current And Voltage

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