1. Voltage Security Margin Assessment Professor Dr. Garng Huang PS ERC

2. Task 1 zModeling of control devices, loads and transactions for stability evaluations. Subtasks z1.1 Modeling FACTS devices [3] z1.2 Modeling Tap-changing transformers for its reactive power drawing capability [8] z1.3 Modeling exciters for its reactive power supporting and voltage regulatingcapability [6,8] z1.4 Modeling loads [8] z1.4 Modeling transactions [5,9,10] Task 2 zUse of Stability Margin and Stability Index Calculations Subtasks z2.1.Develop a program according to the new models to simulate the dynamic responses [4,8] z2.2.Analysis of Modeling Impacts [6,7] z2.3.Use of stability indices as a transaction scheduler [1,2] z2.4Use of utilization indices developed in 2.2 as basis for auxiliary service charges. [5,6,7,11] z2.5Use of 2.4 results as equipment investment indicators based on 2.4 results [5,6,7]

3. Task 3 zTransaction based stability margin and utilization factors calculation Subtasks z3.1 Formulate the transaction based power flow analysis problem [9,10,11] z3.2 Develop software for transaction based power flow analysis for decompositions [9,10] z3.3 Develop software to calculate utilization factor for control equipments [6] z3.4 Develop software for finding decomposed utiliziation factors and stability margins for individual transactions. [5] z3.5Combining results from 3.2 and 3.3 to decompose the margins and utilization factors to individual transactions. [5,6]

4. z1. G M Huang, N C Nair, “An OPF based Algorithm to Evaluate Load Curtailment Incorporating Voltage Stability Margin Criterion”, Conference proceeding of NAPS 2001, TX. z2. G M Huang, N C Nair, “Voltage Stability Constrained Load Curtailment Procedure to Evaluate Power System Reliability Measures”, IEEE/PES WM 2002, NY z3. G M Huang, N C Nair, ”Incorporating TCSC into the Voltage Stability Constrained OPF Formulation”, IEEE/PES Summer meeting 2002, Chicago. z4. G M Huang, N C Nair, “Detection of Dynamic Voltage Collapse”, IEEE/PES Summer meeting 2002, Chicago. z5. G M Huang, N C Nair, “Allocating Usages of Voltage Security Margin in Deregulated Electric Markets”, Submitted to ISCAS 2003, Thailand. z6. G M Huang, K Men,” Contribution Allocation for Voltage Stability In Deregulated Power Systems ”, IEEE 2002 PES, Summer meeting, Chicago. z7. G M Huang, L Zhao, X Song, “A new bifurcation analysis for power system dynamic voltage stability studies”, IEEE 2002 PES, Summer Meeting, Chicago z8. G M Huang, H Zhang, “Dynamic voltage stability reserve studies for deregulated environment” IEEE 2001 PES, Summer Meeting, Canada z9. G M Huang, H Zhang, “Transaction-Based Power Flow Analysis for Congestion Management and Responsibility Evaluation” presented at 2001 IEEE/PES Winter Meeting, Panel Session: Transmission Congestion Management and Reliability, Columbus, Ohio, Jan. 2001. z10. G M Huang, H Zhang, “Transaction Based Power Flow analysis For Transmission Utilization Allocation” 2001 IEEE/PES Summer Meeting. z11. G M Huang, H Zhang, “Transmission Loss Allocations and Pricing Via Bilateral Energy Transactions” 1999 IEEE/PES Summer Meeting. Publications

5. Voltage Stability Indicator

6. Voltage Stability Constrained OPF Formulation

8. TB-VMA Algorithm: Step 1 Decompose nodal currents based on transactions PX = Pool type transaction TX = N T Bilateral transactions Suffix Q represents the system wide reactive market

9. TB-VMA Algorithm: Step 2 Decompose nodal voltage components from decomposed current components Suffix, PX = Pool type transaction TX = N T Bilateral transactions Suffix Q represents the system wide reactive market

10. TB-VMA Algorithm: Step 3 Complex Power Delivered at Load buses, based on scheduled transactions Suffix, PX = Pool type transaction TX = N T Bilateral transactions

11. Step 3… Continued Index L formulation based on transaction based voltage decomposition Suffix, PX = Pool type transaction TX = N T Bilateral transactions

12. TRANSACTION PATTERN

13. Line parameters

14. Result of TB-VMA with and without line contingency of Line 4-9 outage Index Evaluated at Buses Before Contingency Index Evaluated at Buses After Contingency Transaction #2 of bus 7 increases the load bus 9 index. Because generator at bus 2 is involved in both PX#1 and TX # 2. The above effect is magnified in case of a contingency. Bus 9 is driven closer towards voltage collapse. This is because of loss of support for bus 9 from generator 1 because of loss of line

15. TB-VMA Application Scope zResponsibility Settlement of Voltage Security zNode-wise Voltage Stability Margin Utilization Evaluation zEvolve Transaction Based Pricing Mechanism for Voltage Security zA Tool to confirm whether a Transaction could be committed from voltage security margin viewpoint zA Tool to decide which transaction if curtailed gives maximum effect in case of potential voltage collapse situation