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Reference Number: AA-02108// Views: AA-02108// Created: 2022-11-07 22:45:00// Last Updated: 2022-11-10 12:30:15 Q&A Hypersim line with fault: The propagation delay must be larger than the calculation step Hypersim line with fault: The propagation delay must be larger than the calculation stepWhen using the block "3-phase constant parameter line with fault" user can receive the following error: Background1.- When the "3-phase constant parameter line with fault" is used, Hypersim solver will model this block as a two 3-pase lines in series that split in the location of the fault. For example if we have a 300 km line that has a fault at 50 km, this effectively generates two lines one 250km line and another 50km line as shown in the image: . 2.-For a transmission line the propagation speed "V" is given by the equation : V=1/sqrt(L*C) km/s where L is the inductance (unit H/km) and C the capacitance (unit F/km) of the line. The "3-phase constant parameter line with fault" contains 3 modes as shown in the figure. For the example data shown in the same figure, the equivalent transmission speeds for each mode are: V_mode1=2.0069e+05 km/s V_mode2=2.9317e+05 km/s V_mode2=2.9317e+05+05 km/s 3.- The propagation delay "D_p" of a section of line is the length of the line 'L' in Km divided by the propagation speed "V" previously indicated in point 2: D_p=L/V EXAMPLE 1 Let us assume that we have a timestep of the Hypersim model Ts=50us and that the fault of a 300km line is configured to be at 50 km , the propagation delays D_p from the resulting 50km section and the 250 km section are as follow: All these propagation delays D_p's are greater than the timestep of the model Ts=50us, so the model would run without any issue. EXAMPLE 2 Let us assume that we have a timestep of the Hypersim model Ts=50us and that the fault of a 300km line is configured to be at 5 km , the propagation delays D_p from the resulting 5km section and the 295 km section are as follow: In this case all the propagation delays related to the 5km section of the line are below the 50us simulation timestep, so the 5km fault at a timestep of Ts=50us will generate the error "The propagation delay must be larger than the calculation step" Solution: 1.- Increase the location of the fault so that all the propagation delay of all modes are larger than Ts (this limits the minimum distance at which a fault can be configured) 2.- Decrease Ts so that all propagation delays are larger than Ts (maybe limited by the minimum Ts that a simulator can achieve in real time) user can use the previously discussed concepts and equations to achieve a reasonable compromise that allows the model to run. |