Distribution Reliability Assessment

Reliability Assessment for Distribution

Reliability Assessment

개요

The Reliability Assessment module for ETAP evaluates the availability and quality of distribution power systems. It can also make autonomous decisions to keep grids stable and reliable as more DERs come online. Using flexible input parameters, results can be quickly obtained for both radial and looped systems. Powerful calculation techniques allow engineers to choose the depth of system design and the associated results, and choose from a number of reporting formats.

Analysis of customer failure statistics show that, compared to other portions of electrical power systems, distribution system failures contribute as much as 90% towards the unavailability of supply to a load. These statistics show how important it is to assess the reliability of distribution systems.

This module is suitable for reliability analysis of large-scale distribution systems. By using this module, distribution system reliability can be assessed, and the merits of various resources and modifications can be quantitatively evaluated to make cost-effective decisions to achieve the greatest possible improvement in system reliability.

Features

Produce studies and reports to support long-term planning & redundancy
Model the reliability characteristics of each component
Availability & quality of power assessments
Single or double contingency studies
System-wide and feeder-wide calculations
Optionally include load flow constraints
Calculate maximum load transfer rates
Assess reliability level for the system and at each load point
Indices for customer-oriented, energy (cost) and system reliability
Reliability library data based on IEEE Std 493-2007 (Gold Book) and IEEE Std 3006.8
Unbalanced load flow constraints for alternative sources

Benefits

Accurately assess distribution reliability and potential for consumer interruption at point of service
Determine approaches to achieve optimal system reliability at minimum cost
Pinpoint areas of concern affecting the availability and quality of power supply
Enhance ongoing grid stability and reliability through data-driven decision making and maintenance strategies
Prepare comprehensive reports that demonstrate reliability standards compliance

Capabilities

Calculate indices (scroll down to see the full list)
- Bus and load point reliability
- System reliability
- Energy (cost) indices
Rank element contributions to energy (cost) indices
Consider load flow constraints, including
- Capacity of power supply
- Capacity of branch and its voltage drop
- Minimum voltage of buses
Calculate maximum load transfer rate with respect to load flow constraint
Pinpoint critical elements for load transfer per each element failure
Incorporate load transfer rates in calculation of reliability indices
Select the types of components to include in plots
Multiple phase configurations
Unbalanced system reliability calculation
Datablock visualization
GIS diagram plotting
Apply user-defined parameters & settings

Reporting

Graphical display of reliability results
Load point/bus reliability indices
System reliability indices
EENS & ECOST sensitivity analysis
Load transfer results for load flow constraints

Customer Oriented Indices

Average Load Interrupted per Connected Load Served - ALII
Average Customer Curtailment Index - ACCI
Average Service Availability Index - ASAI
Average Service Unavailability Index - ASUI
Average System Interruption Duration Index - ASIDI
Average System Interruption Frequency Index - ASIFI
Customer Average Interruption Duration Index - CAIDI
Momentary Average Interruption Frequency Index - MAIFI
Momentary Average Interruption Duration Index - MAIDI
Sector interruption cost estimates: Customer Damage Function - CDF
System Average Interruption Frequency Index - SAIFI
System Average Interruption Duration Index - SAIDI
System Customer Total Average Interruption Duration Index - CTAIDI
Other indices including but not limited to: CEMI, CELID, TIEPE, NIEPE

Energy (Cost) Indices

Component parameter library
Element contributions to the EENS & their rankings
Element contributions to the ECOST & their rankings
Expected Energy Not Supplied - EENS sensitivity analysis
Expected Interruption Cost - ECOST sensitivity analysis
Interrupted Energy Assessment Rate - IEAR
Interruption cost library
Order of most contributing components to EENS & ECOST

System Reliability Indices

Average failure rate - l
Average outage duration - r
Annual outage duration - U

All of these indices can be used to evaluate the reliability of an existing distribution system, and to provide useful planning information regarding improvements to existing systems and the design of new distribution systems.

Use of indices helps to efficiently model various power system elements and devices to include their effects on the distribution system reliability, such as fault isolation and load restoration through the operation of switching devices.

In order to analyze the sensitivity of reliability index EENS or ECOST with respect to failure rate of different elements, element contributions to that index and their rankings can be used. The rankings can be for a load point or the overall system.

The indices EENS, ECOST, and IEAR can be specifically for each load point, or for the overall system.

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