1. Transmission Planning in a Modern Market Environment
Siemens Power Technologies International
Transmission Planning in a Modern Market Environment

2. Objectives of Talk
Discuss electric power transmission reliability issues, assessment methods and tools
Present opportunities for applying probabilistic techniques

3. Characteristics of Today’s Transmission System Analysis
Reliable on a system-basis
May vary by location
Prevalence of remedial measures
Designed to survive severe, probable events
Deterministic criteria, typically
Without explicitly predicting likelihood of occurrence

4. Reliability Assessment Approaches
Contingency enumeration
Limit scenarios and contingencies
Monte Carlo simulation
Use random sampling

5. Reliability Criteria Based on previous history of failure phenomena
Mainly deterministic, but reflect relative likelihood of component failures
Defined in terms of:
Scenarios
Analyses
Acceptable/unacceptable conditions

6. Deterministic vs. Probabilistic
Tests system performance under different conditions (N, N-1, N-2, etc.)
Determines contingency outcome
Makes “Pass/Fail” decision
Probabilistic
Reflects risk of equipment failures
Multiple component failures may have more severe consequences, but are less likely to occur (have lower probabilities)

7. Equipment Outage Statistics
Probabilistic calculations require input of equipment outage statistics
Data from historical records of equipment failures
Grouped by equipment type, voltage level, rating kV
Transient
Outages
Temporary & Permanent Outages
Line Related
Terminal Related
F (/mi-yr)
R (hours)
F (/yr)
230
0.010 7
0.100 10

8. Probabilistic Indices
System problem (performance criteria violation) indices
Frequency
Average duration
Probability

9. Loss of Load Indices
Energy not served (MWHr/yr) Bulk power interruption index (1/yr) Bulk power energy curtailment index (Hr/yr) Customer indices: SAIDI & SAIFI

10. Unserved Energy
Varies with load and dispatch Studying only peak load may overestimate unreliability Model a series of load/dispatch conditions
0.0
0.2
0.4
0.6
0.8
1.0
1.2
2000
4000
6000
8000
Hours
Per Unit Load
Load
Served
0.5
0.6
0.7
0.8
0.9
1.0
1.1
2000
4000
8000
Hours
Per unit load
6000

11. Value-Based Reliability
Cost of unreliability Cost of reinforcements/must-run contracts Value-based pricing
System Reliability
Cost
Total Cost
Customer Impact
Reinforcements

12. Deterministic vs. Probabilistic Example
Line is overloaded during the outage of a parallel circuit
Load Center
Generation
Probabilistic
Line is overloaded once a year with an average duration of 5 hours

13. System vs. Customer Focus Example
System Perspective
Line is overloaded by 20% during a circuit outage
Load Center
Generation
Customer Perspective
200 MW of load is interrupted during a circuit outage

14. Generation vs. Transmission Example
Scenario A
Scenario B
Urban
Area
Urban
Area
In-City Generators
Add Tie Lines
Retirement of in-city generation, increased dependence on imports Random outage behaviors of generators and transmission components are different Need to consider probabilistic aspect

15. Comparing Options Example
New generation Equipment upgrades Transmission additions Maintenance changes Pricing change
1000
2000
3000
4000
6000
Cost of Investment
Cost of
Unreliability

16. Maximizing Transfer Capability Example
Transfer limits typically computed according to deterministic basis (N-1) Adopt probability approach to compare risk and reward 2 4 6 8 10 12
300
400
500
600
Transfer Limit
Cumulative frequency per year

17. Transmission Line Ratings Example
Ratings tend to be static Often based on worst case assumptions Solution: develop probabilistic function 10 20 30 40 50 60 70 80 90
100
500
1000
1500
2000
2500
3000
Line Rating (amps)
Static rating
Monitored ratings
% of time

18. Roles of Reliability Location-specific indicators
Parts of power system that are susceptible to failures
Risk-based assessment
Vulnerability to system failures
Customer focused measures
Service quality and reliability
Reliability as a product
Pricing accordingly to level of reliability

19. Thank you for your attention!
Bob Zeles Principal Consultant Siemens Industry, Inc. Siemens Power Technologies International
7810 Shaffer Parkway Suite Littleton, CO 80127
Phone: +1 (303) Mobile: +1 (303)