Problem Recognition and Definition
Power loss in high voltage transmission line has a linear relationship to the loads and has exponential relationship to the current flows in the lines. Several methods available in compensating transmission losses and one the most popular method is utilizing Static Var compensation (SVC) equipment installed at the load side. It is important to analyze the econimical benefit of SVC implementation to solve transmission line loss problem.
As mentioned above, SVC is the most practical used in electric transmission & distribution system while another system has been introduced (new technology) by using AC-DC-AC converter equipped with SVC system.
In this economic analysis both alternatives will be analyzed based on cost savings given and opportunities available from the features of these equipment.
Analysis and Criteria
The attached graph showing increasing trend of MVAr supply from hydro power generation through with distance about 30 kilometers long from the center of loads.
Figure 13-1. MVar generated trend
The average MVAr delivery is 80 MVAr and in this study, reduction to half of this value is technically accepted. Loss from 40 MVAr transmission line is worth to $499,000 per year.
Below are two alternatives with technical capability of both equipment and opportunities provided if the equipment installed.
SVC installation is designed to reduce MVAr delivery from power generation while the AC-DC-AC converter (DC Link) does the same with additional capability to transfer active power (MW) from hydro bus to thermal power station bus system. It provides extended opportunity to shutdown diesel generating plant.
Cost comparison of two generating stations is figured below and will be used as a basis to calculate cost savings:
With opportunities (savings) from the two alternatives are figured below:
And summarized data for this analysis is shown on below table
Table 13-1. Basic data of two alternatives
Equivalent worth method will be used to select the best economical option selected for implementation. And alternatives with the highest PW value at defined MARR will be proposed to management.
MARR 25% will be used in this study with 10 years useful life of equipment.
Below figure shows calculation result among two alternatives. Alternative 1 (SVC) provided negative PW value and alternative 2 (DC Link) provide positive (higher) PW value despite higher investment and yearly operating cost compare to the 1st alternative.
Table 13-2. Study result using PW method
Extended economical analysis using another method can be done in separate page to provide strong justification. More technical study and alternative provided to solve the problem might be done and obtained as part of the next study.
- Sullivan, W.G. Wicks, E.M. Koelling, C.P (2012). Engineering Economy, Fifteenth Ed. (chapter 6, page 233-239).New Jersey: Prentice Hall.
- Deng, Yongan. Reactive Power Compensation of Transmission Lines. Concordia University: retrieved from: http://users.encs.concordia.ca/~lalopes/Courses/IGEE401-F07/TL_Compensation.pdf
- ABB. ABB Advance Power Electronic. ABB Switzerland Ltd. Retrieved from: http://www05.abb.com/global/scot/scot232.nsf/veritydisplay/d20bc6e606717f9bc12576c40043ea95/$file/PCS%206000%20STATCOM_INCO_EN.pdf