Transmission Network Expansion Planning Based On The Visual Basic

First, using VB language to compile the calculation program, the gradually-decrease method was used as the main algorithm, take the multiple document window to design a visualization data processing system, which can friendly show interface. Meanwhile, datPrimaryRS and Data Grid control was used in VB, which can realize the function that the experimental Data could be input dynamically and compiled. So it was convenient for the operator to use and management. Take the18nodes transmission system and the46nodes transmission system of north of Brazil as the research object, put their network parameters (branch data、node data) into Access database, run the program to get the future level network structure, the interface shows friendly and it is convenient to query. Which confirm the availability of the visualization data processing systemSecondly, calculation program was compiled by using MATLAB language, conducting the reliability analysis by using Monte Carlo simulation method, the loss of load probability (LOLP) and Expected Energy Not Served (EENS) was selected as two indicators, respectively analysis the reliability index considering four cases: before and after the line rebuilding, before and after the adjustment of the generated output. the prediction results showed that after carrying out the generated output adjustment measures, EENS can greatly be reduced, which can extremely improve the reliability of power supply; after take the line transformation,the reliability benefits which produced by the line investment is greatly improved. In other words, the lack of power outage costs declined, but it just take a little portion of the total costs, so the reconstruction method that changing the single-circuit of18nodes network to double line is uneconomic. It needs to find an economical and reliability reconstruction way, which can maintain the economic benefits of the electricity sector as well as improve the power supply reliability of the user.With the increase in investment, we know, the reliability of power supply continues to improve, the lack of power outage costs is declining. For a grid, It’s not the better, the more investment. According to the marginal cost, there must be an optimal level of reliability point, which can make the investment equals to the power outage costs, then the total costs is minimal. This article uses Monte-Carlo simulation, add a transmission line to the single-circuit of the planning year18-node network in accordance with the level of effectiveness of the single-circuit, followed by calculating the lack of power outage costs, then draw the investment costs curve and the lack of power outage curve, which related to the reliability of power supply, found that there do exist an intersection, the corresponding line optimized reconstruction program should be taken into consideration under the conditions of the economy and reliability.