| บทคัดย่อ(English) |
This thesis described the design of coordinativeprotection system, which consists of two sections, i.e.the theoretical background study and the developed thesoftware. In the theoretical section, a comprehensivestudy, in the relevant fundamentals on the topicincluding detailed setting calculations on the selecteddevices to be used, is thoroughly presented in thisreport. For the other section, the software is intendedto facilitate the user in designing electricalprotective systems through the "OvercurrentCoordinative Program" written in VISUAL BASIC version3. This program is divided into 3 main parts : 1. Creating the single-line diagram : The userscan select a complete set of electrical protectivedevices used in the market today. After completing theconstruction of the diagram, the program will ask forthe specifications of the devices used in the providedtables. These values will be used for calculatingshort-circuit current in the next part of the program. 2. Calculating short-circuit current in radialdistribution system : After filling all the data in andspecifying fault location in the first part, programwill model the circuit of electrical system on screen.Then, users can apply a special apparatus, designed tofacilitate the users in finding out the short-circuitcurrent at any fault location. 3. Analysing and designing characteristic curvesof the protective devices : Characteristic curves ofdifferent devices in various sizes can be readilyloaded from the program memory according to theequipment patterns created on the single-line diagram.Curve coordination can be easily accomplished byshifting relevant curves for each device. These three parts of the program work together asa single unit. The users can save each part designedfor future correction or used as references. Moreover,the results can be printed through the PRINT functionin the program. |
