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Contingency Identification of Cascading Failures in Power Transmission Networks

Chao Zhai, Hehong Zhang, Gaoxi Xiao, Tso-Chien Pan

TL;DR

This work tackles identifying initial contingencies that trigger cascading blackouts in power networks equipped with FACTS, HVDC links, and protective relays. It casts contingency identification as a nonlinear programming problem and solves it with a Jacobian-Free Newton-Krylov (JFNK) method to avoid Jacobian assembly while handling cascading dynamics. The authors develop a cascading dynamics model, integrate FACTS and protection mechanisms, and validate the approach on the IEEE 118 Bus system, demonstrating that coordinated FACTS and relay actions can markedly reduce cascade size and island formation. The result is a practical framework for proactive resilience analysis and contingency planning in modern transmission systems, with potential extensions to AC-based distribution and transient dynamics.

Abstract

Due to the evolving nature of power systems and the complicated coupling relationship of power devices, it has been a great challenge to identify the contingencies that could trigger cascading blackouts of power systems. This paper provides an effective approach to identifying the initial contingency in power transmission networks, which are equipped with flexible alternating current transmission system (FACTS) devices, high-voltage direct current (HVDC) links and protective relays. Essentially, the problem of contingency identification is formulated in the framework of nonlinear programming, which can be solved by the Jacobian-Free Newton-Krylov (JFNK) method to circumvent the Jacobian matrix and reduce the computational cost. Notably, the proposed identification approach is also applied to complicated cascading failure models of power systems. Finally, numerical simulations are carried out to validate the proposed identification approach on IEEE 118 Bus Systems. The proposed approach succeeds in reconciling the rigorous optimization formulation with the practical modelling of cascading blackouts.

Contingency Identification of Cascading Failures in Power Transmission Networks

TL;DR

This work tackles identifying initial contingencies that trigger cascading blackouts in power networks equipped with FACTS, HVDC links, and protective relays. It casts contingency identification as a nonlinear programming problem and solves it with a Jacobian-Free Newton-Krylov (JFNK) method to avoid Jacobian assembly while handling cascading dynamics. The authors develop a cascading dynamics model, integrate FACTS and protection mechanisms, and validate the approach on the IEEE 118 Bus system, demonstrating that coordinated FACTS and relay actions can markedly reduce cascade size and island formation. The result is a practical framework for proactive resilience analysis and contingency planning in modern transmission systems, with potential extensions to AC-based distribution and transient dynamics.

Abstract

Due to the evolving nature of power systems and the complicated coupling relationship of power devices, it has been a great challenge to identify the contingencies that could trigger cascading blackouts of power systems. This paper provides an effective approach to identifying the initial contingency in power transmission networks, which are equipped with flexible alternating current transmission system (FACTS) devices, high-voltage direct current (HVDC) links and protective relays. Essentially, the problem of contingency identification is formulated in the framework of nonlinear programming, which can be solved by the Jacobian-Free Newton-Krylov (JFNK) method to circumvent the Jacobian matrix and reduce the computational cost. Notably, the proposed identification approach is also applied to complicated cascading failure models of power systems. Finally, numerical simulations are carried out to validate the proposed identification approach on IEEE 118 Bus Systems. The proposed approach succeeds in reconciling the rigorous optimization formulation with the practical modelling of cascading blackouts.

Paper Structure

This paper contains 10 sections, 1 theorem, 32 equations, 8 figures, 3 tables.

Table of Contents

  1. Introduction
  2. Cascading Dynamics
  3. DC Power Flow Model
  4. FACTS Devices
  5. HVDC Links
  6. Protective Relay
  7. Optimization Formulation
  8. Numerical Method
  9. Simulation and Validation
  10. Conclusions

Key Result

Proposition 3.1

The optimal solution $\delta^{*}$ to Optimization Problem (formulation) with the multipliers $\mu_1$ and $\mu_2$ satisfies the KKT conditions where $x_i$ and $y_i$, $i\in I_2$ are the unknown variables.

Figures (8)

  • Figure 1: Cascading failure process of power transmission networks.
  • Figure 2: Control diagram of TCSC on branches.
  • Figure 3: Schematic diagram of monopolar HVDC link and its equivalent circuit.
  • Figure 4: Initial state of IEEE 118 Bus System. Red balls denote the generator buses, while blue ones stand for the load buses. Cyan lines represent the branches of power systems. In addition, the red line is selected as the disturbed branch, and three blue lines are the HVDC links, including Branch 4, Branch 16 and Branch 38.
  • Figure 5: Final configuration of IEEE 118 Bus System without FACTS devices.
  • ...and 3 more figures

Theorems & Definitions (4)

  • Proposition 3.1
  • proof
  • Remark 3.1
  • Remark 4.1