The increase of extreme weather events with wide-area enduring adverse impact has caused enormous loss to power systems. Coordination of various emergency measures can effectively reduce the overall loss over the time-horizon of these events. However, coordination of preventive dispatch, emergency dispatch, and restorative dispatch in transmission systems under extreme weather conditions has not been thoroughly addressed. To fill this gap, we first propose a methodology to coordinate the above dispatch stages based on a novel hierarchical defender-attacker model (HDAM). In this model, various dispatch stages are modelled as defenders, whereas the extreme weather event is modelled as the attacker. Second, frequency security constraints, load shedding, and transmission line switching are modelled with the piecewise linear AC power flow in the HDAM. Particularly, an adaptive approximation of cosine function in the piecewise linear power flow equation is applied to greatly reduce the computational complexity. Third, the HDAM is recast as a two-stage robust optimization model with binary decision variables in the recourse stage and solved by the nested column-and-constraint generation algorithm. Then, the robust resilience trapezoid and coordinated strategy during extreme weather events are obtained by the proposed methodology. Moreover, by inference-based sensitivity analysis of the discrete line outage scenarios, the critical transmission lines and transformers are identified for pre-event hardening. Comprehensive case studies using IEEE benchmark systems and a Chinese 132-bus system validate that coordination of multiple dispatch stages is effective to enhance power system resilience against extreme weather events by reducing the overall loss.

To deal with the high dimensionality and computational density of the Optimal Power Flow model with Transient Stability Constraints (OTS), a credible criterion to determine transient stability is proposed based on swing curves of generator rotor and the characteristics of transient stability. With this method, the swing curves of all generator rotors will be independent one another. Therefore, when a parallel computing approach based on the MATLAB parallel toolbox is used to handle multi-contingency cases, the calculation speed is improved significantly. Finally, numerical simulations on three test systems including the NE-39 system, the IEEE 300-bus system, and 703-bus systems, show the effectiveness of the proposed method in reducing the computing time of OTS calculation.

Automatic voltage regulator (AVR) and power system stabilizer (PSS) as the most common excitation controllers have implemented incompatible decentralized control (IDC) due to the asynchronous sampling by the voltage/current transformer. However, IDC results in the incompatibility of decentralized AVR and PSS in regulating generator dynamics, which seriously reduces the capability of AVR and PSS in improving the power system stability. In this article, the concept of compatible decentralized control (CDC) based on synchronous local measurements is first proposed for the decentralized AVR and PSS to improve the power system stability. The mathematical models on IDC and CDC are, respectively, modeled to represent the compatible characteristics of CDC. The distinguishing feature of the proposed CDC is that the decentralized AVR and PSS can be compatible with one another in regulating generator dynamics. Simulation results on four IEEE benchmark systems show the advantages of CDC in improving power system stability compared with IDC.