Open Access Open Access  Restricted Access Subscription or Fee Access

Real-Time Deployment of a Novel Synchrophasor-Based Voltage Stability Assessment Algorithm

Adeyemi Charles Adewole(1*), Raynitchka Tzoneva(2)

(1) Cape Peninsula University of Technology, South Africa
(2) Cape Peninsula University of Technology, South Africa
(*) Corresponding author



This paper proposes a Real-Time Voltage Stability Assessment (RVSA) algorithm based on Classification and Regression Trees (CARTs) for the prediction of the state of the power system and the system’s margin to voltage collapse. A novel RVSA index based on the Effective Generator Reactive Power Reserve (EGRPR) using the field current from synchronous generators is used by the proposed RVSA algorithm. Wide area synchrophasor measurements obtained from Phasor Measurement Units (PMUs) using various scenarios involving the long-term voltage stability dynamics of transformer Under-Load Tap Changers (ULTCs), generator Over-Excitation Limiters (OXLs), and credible contingencies are used in creating the knowledge base for training the CARTs. The trained CARTs are afterwards deployed online in a testbed incorporating a Programmable Logic Controller (PLC) for real-time assessment/prediction. The performance of the proposed algorithm is tested and validated on an equivalent 10-bus multi-machine network using the Real Time Digital Simulator® (RTDS) in a ‘hardware-in-the loop’ architecture with the PLC. Comparisons and analyses made from the results obtained verify the simplicity and accuracy of the proposed RVSA index and algorithm. Their effectiveness for various scenarios such as load variation, topology change, ULTC and OXL actions, are illustrated.
Copyright © 2014 Praise Worthy Prize - All rights reserved.


CART; Decision Trees; Machine Learning; Phasor Measurement Units; Synchrophasors; Voltage Stability Assessment; Wide Area Monitoring System

Full Text:



P. Kundur, Power System Stability and Control (McGraw-Hill, 1994).

C.W. Taylor, Power System Voltage Stability (McGraw-Hill, 1994).

T. Van Cutsem, C. Vournas, C., Voltage Stability of Electric Power Systems (Kluwer Academic Publishers, 1998).

Lauria, D., Pisani, C., Transient stability assessment based upon differential transform method, (2012) International Review of Electrical Engineering (IREE), 7 (4), pp. 4925-4935.

Chiodo, E., Lauria, D., Pisani, C., Villacci, D., Transient stability margins evaluation based upon probabilistic approach, (2013) International Review of Electrical Engineering (IREE), 8 (2), pp. 752-761.

P. Kessel, H. Glavitsch, “Estimating the voltage stability of a power system,” IEEE Transactions on Power Delivery, vol. 1, n. 3, 1986, pp. 346-354.

O.O. Obadina, G.J. Berg, “Identifying electrically week and strong segments of a power system from a voltage stability viewpoint,” IEE Proceedings, vol. 137, n. 3, 1990, pp. 205-212.

V. Ajjarapu, B. Lee, “Bifurcation Theory and Its Application to Nonlinear Dynamical Phenomena in An Electrical Power System,” IEEE Transactions on Power Systems, vol. 7, n. 1, 1992, pp. 424-431.

B. Gao, G.K. Morison, P. Kundur, P. “Voltage stability evaluation using modal analysis,” IEEE Transactions on Power Systems, vol. 7, n. 4, 1992, pp. 1529-1542.

V. Ajjarapu, P.L. Lau, S. Battula, S., “An optimal reactive power planning strategy against voltage collapse,” IEEE Transactions on Power Systems, vol. 9, n. 2, 1994, pp. 906-917.

R.S. Tare, P.R. Bijwe, “A new index for voltage stability monitoring and enhancement,” Electrical Power & Energy Systems, vol. 20, n. 5, 1998, pp. 345-351.

Y. Wang, W. Li, J. Lu, “A new node voltage stability index based on local voltage phasors,” Electric Power Systems Research, vol. 79, 2009, pp. 265-271.

H.G. Kwatny, A.K. Pasrija, L.Y. Bahar, “Static Bifurcations in Electric Power Networks: Loss of Steady-State Stability and Voltage Collapse,” IEEE Transactions on Circuits and Systems, vol. 33, n. 10, pp. 981-991, 1986.

Armenta, S.M., Fuerte-Esquivel, C.R., and Becerril, R., “A numerical study of the effect of degenerate Hopf bifurcations on the voltage stability in power systems,” Electric Power Systems Research, vol. 101, 2013, pp. 102-109.

P.A. Lof, T. Smed, G. Andersson, D.J. Hill, “Fast Calculation of a Voltage Stability Index,” IEEE Transactions on Power Systems, vol. 7, n. 1, 1992, pp. 54-64.

A.Y. Abdelaziz, M.M. Abu-Elnaga, M.A. Elsharkawy, K.M. Elbahrawy, “Voltage Stability Assessment of Multi-Machine Power Systems Using Energy Function and Neural Networks Techniques,” Electric Power Components and Systems, vol. 34, 2006, pp. 1313-1330.

M. Moghavvemi, O. Faruque, O., “Real-time contingency evaluation and ranking technique,” IEE Proceedings, vol. 145, n. 5, 1998, pp. 517-524.

K. Vu, M. Begovic, D. Novosel, M.M. Saha, “Use of Local Measurements to Estimate Voltage-Stability Margin,” IEEE Transactions on Power Systems, vol. 14, n. 3, 1999, pp. 1029-1035.

B. Milosevic, M. Begovic, “Voltage-Stability Protection and Control Using a Wide-Area Network of Phasor Measurements,” IEEE Transactions on Power Systems, vol. 18, n. 1, 2003, pp. 121-127.

M.M. Hamada, A.A. Wahab, N.G.A. Hemdan, “Simple and efficient method for steady-state voltage stability assessment radial distribution systems,” Electric Power Systems Research, vol. 80, 2010, pp. 152-160.

J.E. Tobon, R.E. Correa Gutierrez, J.M. Ramirez, “Voltage collapse detection based on local measurements,” Electric Power Systems Research, vol. 107, 2013, pp. 77-84.

L. Warland, A.T. Holen, “Estimation of Distance to Voltage Collapse: Testing and Algorithm Based on Local Measurements,” Proceedings of 14th Power System Computation Conference, vol. 38, 2002, pp. 1-7, Sevilla, Spain.

M. Zima, M. Larsson, P. Korba, C. Rehtanz, G. Andersson, “Design aspects for wide-area monitoring and control systems,” Proceedings of the IEEE, vol. 93, n. 5, pp. 980-996, 2005.

M. Larsson, C. Rehtanz, J. Bertsch, “Real-Time Voltage Stability Assessment of Transmission Corridors,” Proceedings of IFAC Symposium on Power Plants and Power Systems, 2003, pp. 1-6, Seoul, S. Korea.

L. Bao, Z. Huang, W. Xu, “Online Voltage Stability Monitoring Using VAR Reserves,” IEEE Transactions on Power System, vol. 18, n. 4, 2003, pp. 1461-1469.

B. Leonardi, V, Ajjarapu, “Investigation of Various Generator Reactive Power Reserve (GRPR) Definitions for Online Voltage Stability/Security Assessment,” Proceedings of 2008 IEEE PES General Meeting, vol. 554, 2008, pp. 1-7, Tampa, USA.

S. Corsi, “Wide area voltage protection,” IET Generation, Transmission & Distribution, vol. 4, n. 10, 2010, pp. 1164-1179.

R.A. Schlueter, “A Voltage Stability Security Assessment Method,” IEEE Transactions on Power System, vol. 13, n. 4, 1998, pp. 1423-1438.

D. Feng, B.H. Chowdhury, M.L. Crow, L. Acar, “Improving voltage stability by reactive power reserve management,” IEEE Transactions on Power System, vol. 20, n. 1, 2005, pp. 338 – 345.

H. Song, B. Lee, Y.H. Moon, “Reactive Optimal Power Flow incorporating margin enhancement constraints with non linear interior point method,” IEE Proceedings on Generation Transmission and Distribution, vol. 152, n. 6, 2005, pp. 961-968.

P.A. Ruiz, S.W. Sauer, “Reactive Power Reserve Issues,” North American Power Symposium (NAPS 2006), 2006, pp. 439-445.

T. Van Cutsem, L. Wehenkel, M. Pavella, B. Heilbronn, M. Goubin, “Decision tree approaches to voltage security assessment,” IEE Proc. on Generation, Transmission and Distribution, vol. 140, n. 3, 1993, pp. 189-198.

P. Geurts, L. Wehenkel, “Temporal machine learning for switching control,” Proceedings of 4th European Conference of Principles and Practice of Knowledge Discovery in Databases (PKDD), 2000, pp. 401-408, Lyon, France.

R.F. Nuqui, A.G. Phadke, R.P. Schulz, P. Richard, N. Bhatt, “Fast On-Line Voltage Security Monitoring Using Synchronized Phasor Measurements and Decision Trees,” IEEE Power Engineering Society Winter Meeting, vol. 3, 2001, pp. 1347-1352.

V. Vittal, “Application of phasor measurements for dynamic security assessment using decision trees,” IEEE Power and Energy Society General Meeting, 2012, pp. 1-3.

R. Diao, K. Sun, V. Vittal, R.J. O’Keefe, M.R. Richardson, N. Bhatt, D. Stradford, S.K. Sarawgi, “Decision Tree-Based Online Voltage Security Assessment Using PMU Measurements,” IEEE Transactions on Power Systems, vol. 24, n. 2, 2009, pp. 832-839.

B. Avramovic, L.K. Fink, “Real-time Reactive Security Monitoring,” IEEE Transactions on Power Systems, vol. 7, n. 1, 1992, pp. 432-437.

B. Leonardi, V. Ajjarapu, “An Approach for Real Time Voltage Stability Margin Control via Reactive Power Reserve Sensitivities,” IEEE Transactions on Power Systems, vol. 28, n. 2, 2013, pp. 615-625.

I.H. Witten, E. Frank, M.A. Hall, Data Mining: Practical machine Learning Tools and Techniques (Morgan Kaufmann Publishers, 2011).

L. Breiman, J. Friedman, R.A. Olshen, C.J. Stone, Classification and Regression Trees (Belmont, Wadsworth, 1984).

L. Wehenkel, T. Van Cutsem, M. Pavella, “An artificial intelligence framework for on-line transient stability assessment of electric power systems,” IEEE Transactions on Power Systems, vol. 4, n. 2, 1989, pp. 789-800.

MATLAB Statistic Toolbox: User’s Guide (The MathWorks Inc., Natick, Massachusetts, 2013).


  • There are currently no refbacks.

Please send any question about this web site to
Copyright © 2005-2022 Praise Worthy Prize