Reliability and Restoration Analysis

What is reliability assessment?

Network reliability assessment is an automated and probabilistic contingency evaluation used to calculate expected interruption frequencies and annual interruption costs and express the outcome in terms of standard indices. It takes into account statistical data about the expected frequency and duration of outages, together with information about protection systems and the network operator’s actions for restoring supply.

What does PowerFactory‘s Reliability and Restoration Analysis module include?

As well as the reliability assessment and calculation of standard indices, the module includes functions for determining restoration sequences, and functions for optimising the network to improve reliability. In addition, Generation Adequacy Analysis and Loss of Grid Assessment tools are included.

• Line/cable, transformer, distribution transformer, busbar and circuit breaker failures
• Generator failures with stochastic multi-state model
• n-1, n-2 and common mode failures (n-k)
• Double earth faults
• Independent second failures
• Protection/circuit breaker failures
• Protection over-function

• Fast state enumeration for balanced/unbalanced systems, including optimal power restoration techniques
• Calculation of all common reliability indices (IEEE 1366)
• Contribution of components to reliability indices
• Support of load variation, including load distribution curves
• Support of generation dispatch profiles
• Consideration of maintenance schedules
• Support of various tariff and cost models
• Parallelised Reliability Assessment using multiple cores

• Failure effect analysis (FEA)
  
  • Automatic protection-based fault clearing
  • Intelligent high-end system restoration with potential network ­reconfiguration and load-shedding
  • Support of branch and boundary flow limits, absolute ­voltage and voltage drop/rise constraints
  • Sectionalising (remote controlled switches, short-circuit ­indicators, manual restoration)
  • Substation automation with switching rules
• Animated tracing of individual cases
• Detailed reports for restoration action plans

• Fault analysis that includes analysis of post-fault conditions after restoration measures for distribution systems
• Possible for both radial and meshed networks, incorporating a sophisticated power restoration algorithm, respecting branch and voltage constraints
• Tabular reports and trace function for visualisation of restoration actions and results
• Automatic contingency definition including support for pre-defined library fault cases

• Determination of optimal number and locations for RCS installation for improvement of system reliability
• Economic assessment for various objective functions

• Calculation of optimal switching scheme for manual power restoration phase

• Optimal locations for reclosers, to improve reliability indices

• Stochastic assessment of system supply capabilities (loss of load probabilities, capacity credit, etc.)
• Consideration of generator outages and maintenance schedules (Monte Carlo), as well as load variation
• Enhanced probabilistic models for wind generation
• Rich suite of reporting and plotting tools

• Risk assessment for loss of grid supply to critical power stations