© 2015 ETAP & Operation Technology, Inc.
Contingency AnalysisETAP 14
Innovation AutomationCollaboration
© 2015 ETAP & Operation Technology, Inc.
Agenda
• Introduction• Concepts• ETAP Contingency Analysis (CA)• Examples
© 2015 ETAP & Operation Technology, Inc.
Who
• Industries• Systems
• Three phase• AC Systems
© 2015 ETAP & Operation Technology, Inc.
Introduction
• Power systems are operated such that they maintain system security
• There should not be any “reliability” violations in real‐time or likely contingencies:• Equipment failure• Loss of generating unit• Load shedding• Loss of transmission or sub‐transmission component
• Power system planning & operation requires study of outages & its severity
© 2015 ETAP & Operation Technology, Inc.
Contingency Types
• Probabilistic – Reliability Assessment Module• Statistical – Contingency Analysis Module
© 2015 ETAP & Operation Technology, Inc.
Contingency Analysis
• Contingency Analysis is an important tool for design and operation of a power network
• Planning, Engineers• Evaluate feasibility and security based on the ability of the network to resist failures
• Operations, Dispatcher• Evaluate new system conditions at regular intervals
• Provides an automatic way of analyzing all statistically likely contingencies
© 2015 ETAP & Operation Technology, Inc.
Methodology
• Disable a particular part (branch) and evaluate network stability using power flow
• Post‐contingency criteria• No transmission line/transformer limit violations• Bus voltages within acceptable limits
• Engineers can rank the system to prioritize planning & improvements
© 2015 ETAP & Operation Technology, Inc.
Key Definitions & Criteria
• Number of branches disabled determines the (N‐x) contingency analysis
• N‐1 Contingency = Loss of single device • N‐2 Contingency = Loss of two devices simultaneously
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Performance or Security Index
• Outage ranking against Base Case or Equipment Rating
• Index indicates severity of the outage• Number without units hence can be combined
© 2015 ETAP & Operation Technology, Inc.
Why ETAP
• N‐1 & N‐2 contingency ranking and assessment• Fast screening method
• Scan outage list • Identify higher risk contingencies for further evaluation
• Multiple graphical outage lists
© 2015 ETAP & Operation Technology, Inc.
Why ETAP
• Automatic performance indices calculation• Bus Voltage Security V/Vsp• Real Power Flow Change ΔP• Reactive Power Flow Change ΔQ• Branch Overloading Security S/Ssp
© 2015 ETAP & Operation Technology, Inc.
Time Saving Features
• Summary report analyzer• Complete load flow• Interrupted generation power loss• Interrupted customer power loss• Interrupted number of customers• Interrupted power lost cost
• Compare base load flow with contingency load flow