Test Specification for Design of Power Capacitors for Power Factor Improvement in a Power Distribution System submitted to: Professor Joseph Picone ECE 4522: Senior Design II Department of Electrical and Computer Engineering Mississippi State University Mississippi State, Mississippi 39762 September 14, 2000 submitted by: Page J.C., Parson L.B., Watson K.M., Wong C.S. Faculty Advisor: Dr. Stanislaw Gryzbowski Department of Electrical and Computer Engineering Mississippi State University Box 9571 Mississippi State, Mississippi 39762 email: {jcp2, lbp1, kmw2, csw1}@ece.msstate.edu DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERINGExecutive Summary In the power distribution industry today, utility companies are trying to come up with a solution to increase the efficiency of distributed power. One way of achieving this task is by improving the power factor of a system by adding power factor correction capacitors. Power factor improvement is a very important aspect of power distribution. Without a good power factor, there cannot be an efficient means of transporting energy over long distances due to the losses associated with moving power through a wire. This action has led to multiple studies on power factor correction. In order to achieve maximum efficiency, we had to increase our power factor as close to unity as possible. We accomplished this controlled boost of power factor by installing the proper number of specifically designed high voltage power capacitors at the substation. In designing our capacitors, there were certain design constraints that had to be met and overcome. Our capacitors were designed according to established IEEE standard 18-1992. In addition, our capacitor bank was built around an average load on a typical substation. This typical substation is rated at 15kV and during the peak hours of the day, its load of 3MW draws a total of 2MVAR of reactive power. Using these typical specifications, a bank of forty (40) capacitors was designed with each capacitor contributing 50kVAR of reactive power. These forty (40) capacitors were also economically feasible. Another constraint that had to be overcome was the capacitors' exposure to environmental conditions. Our capacitors are able to withstand a corrosive environment and a wide variety of weather conditions such as extreme temperatures and lightning. Upon meeting all of the design constraints, our capacitors have long lifetime expectancy. In overcoming the design constraints, several techniques have been incorporated. We researched the problem thoroughly and took into account the design parameters. We contacted several manufactures to learn about the construction of capacitors. Certain calculations were performed to determine the dimensions and the physical construction of the capacitor. Next, we used simulation tools (SuperHarm, Excel, and PSpice) to prove our design were feasible. After these appropriate simulations were conducted, we tested the model capacitors in Mississippi State University's High Voltage Laboratory in order to verify their design functions and performance. We compared our test results with our design constraints and our goals were met. Due to the fact that using capacitors to correct a power factor has been around for many years, we are not the first to design and build a high voltage power capacitor. However, the innovativeness of our project comes into play when one considers the careful insulation process and materials used to extend the capacitors’ life and efficiency. The future of capacitor design to correct power factor will be based on finding new materials that provide better insulation between the foil sheets. Today, researchers are trying to employ new high-tech polymer as the dielectric in capacitors. This will allow for higher voltages and smaller physical dimensions of the capacitor to be attained.1. Introduction When producing any kind of product for sale to the public, a company must be concerned with the cost and quality of the final product; hence in our case, the final product is a supply of power to customers. To deliver power to customers efficiently, losses associated with transporting energy through a wire must be cut to a minimum and in order to accomplish this task, a power factor ratio must be addressed. A tank of power capacitors will be connected to the power distribution system to raise the power factor, which will minimize losses. The significance of our solution will save utility companies money because energy will not be wasted or lost. The design constrains of our proposed system are: 1. We will reduce voltage drop in transmission lines going to the substation which will in turn increase the substation voltage by 5% (around 750 volts). 2. We will reduce the current in power lines by 15% in order to reduce the energy lost in power lines by 30%. 3. We will provide a total of 2MVAR reactive power to the substation for necessary power factor correction. 4. The voltage rating across the capacitor will be 8.66kV. 5. We will achieve a power factor of at least 90%. 6. We will reduce the cost of transmitting power by 30%. 7. Our capacitor will be enclosed in a stainless steel container with two porcelain bushings so it can withstand harsh environmental elements. 8. Increase system capacity by 20%. 9. Discharge to less than 50V in under 5 minutes. 10. Low dielectric loss (tan δ) (0.1w/kVAR). 1.1. Reduce Voltage Drop and Energy Loss When more reactive power is demanded by the loads, the current drawn through the transmission line increases. This increase in current causes an increase in voltage drop across the lines and in turn, causes an overall lower substation voltage. In order to solve this problem, power factor correction capacitors are needed. These capacitors will supply the necessary reactive power required by the load, which will raise the voltage of the substation. In addition to reducing the voltage drop, the reactive power supplied by the capacitors will also reduce the total current in the transmission lines coming to the substation. This reductionin line current reduces the apparent power that is lost in the transmission lines; hence, the energy loss has been reduced. Once this energy loss has been reduced, the cost of transmitting power becomes less expensive since there is a more efficient operating power system. 1.2. Total Reactive Power of 2MVAR With A Corrected Power Factor of At Least 90% In order to correct
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