NEPLAN | Reliability Analysis

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Reliability Analysis module is used to determine the frequency, average duration and cost of network component failures, leading to supply interruptions. Analysis takes into consideration the outage behaviour of network equipment (failure rate and repair times), the network operation in normal state and for multiple order network contingencies. Admissible short-time component overloading are also accounted for. Realistic generation patterns and load curves are used while the module implements a protection concept including protection failures.

Contingencies dealt with can be stochastic failures or overlapping independent stochastic failures, common-mode failures, protection failure or overfunction, multiple earth faults, spontaneous protection tripping, or failure occurring during the maintenance of the backup components.


  • Optimal asset allocation and cost-benefit analysis for investments in transmission and distribution networks
  • Design and evaluation of innovative substation layouts
  • Weak-point analysis in existing networks
  • Design of automation concepts in public and industrial distribution networks
  • Detailed and objective discussion of network connection concepts for high-demand customers and power plants
  • Cost-effective mitigation of power quality problems (voltage sags)
  • Add-on for NEPLAN-Main – a tool to apply Reliability Centred Maintenance (RCM) Strategy, which leads to substantial reduction of maintenance expenses


Result values are printed at load nodes in network graph, which can be colour shaded according to the Reliability Analysis outcome.  Results are fully exportable for use in tables and diagrams and comprise of:

  • Frequency of supply interruptions
  • Probability of supply interruptions
  • Mean interruption durations
  • Energy not served in time
  • Interruption cost

Evaluation Functions

Reliability Analysis module provides various flexible filter and diagram functions to visualize results and facilitate analysis:

  • Consideration of power/energy-specific interruption cost
  • Filter to investigate component contributions to load node interruptions
  • Shading of network diagram in dependence of load node results
  • Analysis of system reaction after faults
  • Copying of diagrams into clipboard