electricpy.fault.tdradial

electricpy.fault.tdradial(I, CTI, Ipu_up, Ipu_dn=0, TDdn=0, curve='U1', scale=2, freq=60, CTR_up=1, CTR_dn=1, tfixed=None)[source]

Radial Time Dial Coordination Function.

Function to evaluate the Time-Dial (TD) setting in radial schemes where the Coordinating Time Interval (CTI) and the up/downstream pickup settings are known along with the TD setting for the downstream protection.

Parameters:

  • I (float) – Measured fault current in Amps, typically set using the maximum fault current available.

  • CTI (float) – Coordinating Time Interval in cycles.

  • Ipu_up (float) – Pickup setting for upstream protection, specified in amps

  • Ipu_dn (float, optional) – Pickup setting for downstream protection, specified in amps, default=0

  • TDdn (float, optional) – Time-Dial setting for downstream protection, specified in seconds, default=0

  • curve (string, optional) – Name of specified TOC curve, may be entry from set: {U1,U2,U3,U4,U5,C1,C2,C3,C4,C5}, default=U1

  • scale (int, optional) – Scaling value used to evaluate a practical TD setting, default=2

  • freq (float, optional) – System operating frequency, default=60

  • CTR_up (float, optional) – Current Transformer Ratio for upstream relay. default=1

  • CTR_dn (float, optional) – Current Transformer Ratio for downstream relay. default=1

  • tfixed (float, optional) – Used to specify a fixed time delay for coordinated protection elements, primarily used for coordinating TOC elements (51) with OC elements (50) with a fixed tripping time. Overrides downstream TOC arguments including Ipu_dn and TDdn.

Returns:

TD – Calculated Time-Dial setting according to radial scheme logical analysis.

Return type:

float