NEPLAN | Short Circuit Analysis

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This module performs Short Circuit Analysis on 3-phase, 2-phase and 1-phase AC and DC systems, for single-, two- (with and without earth connection) and three-phase faults. It provides the option of computing line faults or even user-defined fault types such as double earth faults, faults between two voltage levels, conductor opening, etc.

General Characteristics

  • Standards IEC909 1998, IEC60909 2001, IEC60909 2016, ANSI/IEEE C37.10/C37.13, G74 Engineering Recommendation
  • IEC 61363-1 for off-shore/ship plants
  • IEC 61660 for DC networks
  • Superposition method with consideration of prefault voltages from a load flow
  • Computable fault current types: initial symmetrical short-circuit current and power, peak, breaking, steady state, thermal and asymmetrical breaking current, plus DC component
  • Computation of minimum/maximum short-circuit current
  • Accurate model for transformer earthing connection
  • Earthing system for common earthing of any number of transformers, generators, etc.
  • Petersen coil tuning in resonance earthed networks
  • Current limiting due to circuit breakers and MOV
  • Calculation of relay tripping times, e.g. for over current and distance protection
  • Contribution of adjustable frequency drives and static converter to short-circuit currents

Line Coupling

Short Circuit Analysis module allows for mutual impedances and capacitances in the positive and zero-sequence systems which are computed from the conductor configuration. Overhead lines with up to 6 3-phase systems and 3 earth wires can be computed (earthing of 3-phase systems considered) while unrestricted number of overhead lines can be entered. Finally, parameters and conductor configuration are saved.

Results

Upon calculation results are automatically displayed on the single line diagram while their content and graphical information can be customized. Display of results is node oriented and can be inserted at any node or element. Result evaluation and processing is easier due to visualization functions:

  • Overloaded pieces of equipment (current transformers, voltage transformers, circuit-breakers, etc.) are highlighted
  • Output list is sorted by voltage levels. Short-circuit impedance and all computable fault currents are displayed as phase values or as symmetrical components
  • Results can be saved in a result file and SQL database