AUTOMATED CALCULATION OF PARAMETERS FOR RURAL 0.4 KV POWER TRANSMISSION LINES FOR AGRO-INDUSTRIAL FACILITIES

Abstract

The purpose of the study is to develop and test a software-based calculation algorithm for automated assessment of the parameters for rural 0.4 kV power transmission lines, taking into account the 10/0.4 kV transformer, conductor parameters, the length of the supply section and agro-industrial facility loading. The methodology includes formation of a computational scheme, determination of operating current, variant calculations for different lengths and cross-sections of the line. The methodology takes into account the parameters of the TMG [oil-filled waterproofed transformer]-250/10/0.4 kV transformer such as power 250 kVA, short-circuit voltage 4.5%, short-circuit loss 3.7 kW. The initial load of 51 kW is represented as a mixed load of an agricultural facility with electric motor and single-phase receivers at the value cosφ = 0.92. The results of approbation were obtained for the SIP [self-supporting insulated wire]-4 4×50 mm2 line. It has been found that with a length of 167.4 m, the voltage loss is 5.06%, and with a length of 450 m it increases to 13.59%, which exceeds the accepted design limit of 8%. A series of calculations has shown that switching to the SIP-4 4×95 mm2, reducing the length of the supply section or sharing the load between two feeders make it possible to ensure an acceptable mode. A control comparison with manual calculation and the R-X model has shown a discrepancy of no more than 0.34 %. The software support is implemented in Python with a graphical interface and report generation. The practical significance consists in reducing the complexity of the multivariate calculation and in increasing the substantiation of decisions on reconstruction of rural networks of 0.4 kV.