The Load Process And Compensation Scheme Of The Unequal Capacity Vx Traction Transformer

The load condition of the traction transformer secondary side winding and the power quality of substation is analyzed using measured data of The Dragon Palace traction substation which employs Vx traction transformers of different capacity. Simultaneously, on the basis of the traction transformer temperature rise and loss of life computational model, maximum temperature of the four windings of the traction transformer secondary side and days of life lost and analysis Vx traction transformer secondary-side winding overload capacity is calculated. Serious overload situation of the FN winding and negative-sequence problem of three-phase lateral is found.Against the serious overload situation of the Vx traction transformer secondary side FN winding serious problem of three-phase side of the negative sequence, the program of replacing Vx traction transformer is put forward, and direct power supply scheme of introducing the dual windings in parallel of VV+with strengthen line is proposed,as well as the balance compensation scheme. A detailed analysis of the balance compensation program is carried out, and a based Static Var Generator (SVG) traction transformer balanced compensation device is analyzed. It is shown that the balance compensation device is capable of active power transfer from phase in TN winding to the FN winding, and can solve the F-N winding overload problem, while it is also used to balance the traction on both sides of the side power and compensate the reactive component of both sides. Finally, the purpose of the elimination of the negative sequence component of the three-phase side is achieved.In-phase compensation package and inter-phase compensation principle is proposed for solving the overload problem and dealing with the negative-sequence. Temperature rise and the life loss condition of each winding is analyzed after the in-phase compensation goal is determined based on the installed capacity of secondary winding. Calculation of Vx traction substation negative sequence current is discussed. Changing three-phase current to three-phase symmetry current is adopted as the target of compensation. According to the SVG structure and control principle, the mechanism of in-phase compensation package and inter-phase compensation principle is analyzed, and a compensation strategy is adopted. SVG direct current control needs real-time detection of fundamental reactive current. The current detection method adopts the current indirect assay based on the FBD method and the current tracking control method uses SPWM.The load is structured using measured data of traction substations. Modeling and simulation of in-phase and inter-phase compensation is achieved using Matlab/Simulink. The simulation results of each winding load condition and negative sequence current size of three-phase side are use as appraisal standards to verify the compensation scheme. It is verified that the scheme can solve the overload problem of the Vx traction the FN winding of the transformer secondary side and the three-phase side of the negative sequence problem.