| With the rapid development of national economy, the demand for electricity in different industries is increasing. As an important part of power system, the safe and reliable operation of substation is closely related to the development of national economy. In order to meet the rapidly increasing load demand in Longjiao Township and improve the power supply capacity and reliability of this area, there is a certain theoretic value and practical significance to research the rational planning of Longjiao 110 kV substation. By taking Longjiao 110 kV substation as the research object, this paper researched a set of electricity design of substation. The main work and research content are as follows:1. The method of electrical load prediction were clarified, then the historical load growth trend and load characteristics were analyzed and the annual electricity consumption of the whole society from 2016 to 2029 in Longjiao area was respectively predicted as well. Combined with planning scheme of electric power system of Longjiao area, the recent and prospective main transformer capacity and number were determined. In additional, considering the aspect of reliability, flexibility and economy, the main electric connection mode of Longjiao 110 kV substation was designed accordingly.2. Based on the system planning data, the short-circuit current of each short circuit point under maximum working mode was calculated, based on which the starting value of short circuit current period, effective value of steady state short circuit current, maximum impact value of short circuit current and maximum effective value of short circuit current were obtained. What’s more, all the electric equipments and parameter of conductors in each loop of 110 k V and 10 kV substation were confirmed on the basis of normal working condition, short circuit condition and dynamic and thermal stability calibration. Furthermore, the parameter of incoming conductor was determined based on Longjiao variable capacity as well as wind power capacity, and the station capacity was also decided as per statistics of station load.3. Through the reactive loss calculation of main transformer winding under 30% and 80% load, it is found that the power factor at the side of high voltage was lower. In order to make the power factor at high voltage side to be 0.95, the configuration combination of reactive power compensation capacity was calculated and determined. Moreover, arc suppression coil capacity was decided through calculating the capacitive current of 10 kV circuit. According to the arrester selection of 110kV-side, 10kV-side and main transformer neutral point, the insulation level of electric equipment was decided. Based on the calculation of short circuit current, the selection of grounding conduction section was also verified. In additional, the grounding design of substation was confirmed through the calibration of step voltage, contact potential and power frequency counter over voltage.4. According to universal design, half indoor GIS scheme and indoor GIS scheme were considered to be adopted, and then the half indoor GIS scheme was determined at last through the comparison of technical economy of those two designing schemes and analysis of life cycle cost(LCC).After the audit of feasibility study meeting carried out by Fujian Economic Technology Institute of State Grid Corporation of China, the electric design scheme of Longjiao 110 kV substation meets the demand of recent and long term electric load, which resolves the low voltage problem in Longjiao area and thus improved the reliability of power supply in such area. |
