NEPLAN | Overcurrent Protection (Selectivity Analysis)

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This module is used for the coordination of various over-current protection devices in a given network. The response of the over-current protection devices is visualized in the Time-Current Characteristic (TCC) curve. These TCC curves can be viewed on the selectivity diagram using which the user can adjust the settings of these devices to protect the cable, transformer, etc.

General Characteristics

  • All types of protective devices with a current-time characteristic can be entered: fuses, circuit breakers, definite-time and inverse-time over-current relays, electronic relays
  • Several protective functions can be assigned to each protective device: non-directional or directional (over-current and earth-fault protection)
  • Exact modelling of setting ranges
  • Extensive libraries with protective devices from a variety of manufacturers are available and can be extended at will
  • Option for entering user-defined characteristics for simulating motor start-ups or thermal capability of cables, damage curves of transformers, etc.
  • Characteristic can be shifted using a k-factor (inverse-time relay)
  • Entry options for characteristics: point-by-point or formula in conformity with IEC or IEEE/ANSI
  • Simulation of fault clearing procedure in meshed networks, involves also distance protection

Selectivity Diagram

  • Protection device and current transformers are positioned in the network plan graphically
  • Single-line diagram can be viewed in the selectivity diagram
  • Automatic generation of selectivity diagrams based on s/c calculation
  • Unrestricted number of characteristics can be incorporated in one diagram
  • Changing the relay settings directly in the selectivity diagram by moving the curves with mouse or with the help of navigation arrows
  • Unrestricted number of diagrams can be processed simultaneously
  • Selectivity analysis over more than one voltage level and independently of the network type and size involved
  • Two reference voltages for diagrams can be defined by the user
  • Individualized colouring of the characteristics
  • No limit on number of diagrams and protective numbers for management
  • Export of complete diagram to PDF, Word, PNG etc.
  • Possible to print the charts from the selectivity diagram
  • Axis settings and fonts for the labels can be changed in the diagram
  • Short circuit calculation can be done directly from the selectivity diagrams

Transferring Current Values

  • Short circuit currents as well as other currents can be incorporated in the selectivity diagram
  • Unrestricted number of currents can be transferred into one diagram

Protection Libraries

NEPLAN offers extensive libraries with most used relays-, circuit breaker – and fuse-types. The libraries are constantly updated and extended. They will be handed out for free at the moment of a NEPLAN software purchase or can be downloaded any time from the Internet by users with a valid maintenance contract.


Selectivity Charts