Study Of Power Supply Scheme On Altiplano Railway

The QingHai-Tibet railway lies in the QingHai-Tibet altiplano and the all-line 35kV power line must be very long because of there only a little or no power source, so the power supply became very difficult and complexity. The paper's studying is based on this question. The paper analyzes the power supply and puts forward some useful ways in theories to the designer for reference in order to guarantee the reliability and security of the power supply.The paper has five parts.In the introduction, brings forward the questions that would appear in the very long 35kV power transmission lines. The questions are : a) the voltage of the tail end of the line would be higher than that of the first end of the line because of the distributing capacitor of the line when no load or only a little load on the line; b)when there has some loading on the line, the voltage would drop too much, the voltage phase difference between the first and the tail end of the line is very large, the first end of the line would be very heat and it would be diseconomy because power loss in the resistance of the line is very large.In the second part, lines out the calculating formulas for the very long power line.In the 3rd part, simulates the non-loading line and draws out the conclusions that when there is no load on the long line, the voltage of the tail end is the highest and the voltage in the line distributes in line with the cosine order; there has a very large charging current in the line and the voltage of the tail end would be higher after taking into account the power source reactance. Also the part studies the effect of the parallel inductor and points out the parallel inductor would limit the overvoltage of the non-loading line.In the 4th part, analyzes the running of the line when it has different loadings and puts forward the measures to compensate the voltage drop. These measures are: the parallel capacitor, the series capacitor, the dynamic reactive compensation and solar or wind generator and so on. Especially the paper points out that because of the particularity of railway power loads , the effect of seies capacitor is very little.In the 5th part , lines out the inner overvoltage would appear on the very long power line. These voltage are: the overvoltage of non-loading line; the asymmetry fault overvoltage; the intermission arc grounding overvoltage; energization overvoltage and break off overvoltage on the non-loading line.