Line Check

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Line Check


The purpose of this module is to verify a line or cable model. In many cases when creating a higher frequency model for transient analysis some parameters could be uncertain (especially average ground resistivity and conductor height). Very often the only reliable benchmark data available are the power frequency sequential series impedances and shunt admittances (which even could be based on measurements).



Fig. 1. Selecting a line to verify/check


The user invokes this module by selecting a line/cable in the circuit window and then click on ATP|Line Check. First a dialog box appears where the user can select the input and output nodes. ATPDraw suggests the leftmost nodes as input and the rightmost as output. The number of inputs and outputs must be equal and it is possible to change, add, and delete the default suggestions. In case of 3-phase nodes the user must specify the full single phase names including the ABC or DEF extensions (select ATP|Make Name to identify the node names). The user must also select the frequency where the calculations are performed.



Fig. 2. Selecting the inputs and outputs.


ATPDraw then creates a file LineCheck.dat in the LCC-directory. For a 3-phase case 4 sequential data cases are created (6-phase: 12 and 9-phase:24 due to mutual coupling effects) positive  and zero sequence series impedance (output end grounded) and shunt admittance (output end open). ATPDraw then runs ATP and interprets the LineCheck.lis file. To obtain an approximation for the series impedance and shunt admittance currents and voltages at both ends are monitored and equivalent distributions obtained. The equivalent current is i_eq=(i_in+2*i_out)/3 and the voltage is v_eq=(v_in+2*v_out)/3.


The results are presented in the Result window. It is possible to create a text file of the results.



Fig. 3. Results of the line check calculations.