$P$/$\omega $admittance modeling is one of effective techniques to analyze the low-frequency oscillation (LFO). However, existing modeling methods are typically developed for specific control strategies on a case-by-case basis, lacking a general framework. Such case-specific formulations limit the broader applicability of this model in power system studies. To address this limitation, a general$P$/$\omega $admittance modeling framework is proposed based on the equivalence of controlled source and impedance (ECSI). In the proposed framework, the VSC is modeled as a controlled frequency source, which is regulated by both active power and the frequency at the filter terminal, whereas the reactive power-voltage dynamics are modeled as an equivalent admittance in parallel with the line admittance. Such a modeling strategy enables the construction of$P$/$\omega $admittance models for VSCs with diversified controls, using a consistent and intuitive framework. Leveraging the model’s transparency, the LFO characteristics of various VSCs are identified. The case study of a multi-VSC system demonstrates that the proposed model can accurately reflect the interactions among control loops and reveals the characteristics of LFO caused by different controls of VSCs, providing a powerful tool for stability analysis and control design. Finally, comprehensive simulations under various scenarios are conducted to verify the accuracy of the proposed model.

Massive amounts of uncertain demand response (DR) lead to a sudden increase in the data flow of power and thermal cyber-physical system (PTCPS), greatly increasing the blocking risk on critical communication paths of PTCPS. This article proposes a two-stage robust coordinated planning (TRCP) model with decision-dependent uncertainty (DDU), aiming to minimize the investment and improve communication security. First, a hybrid networking strategy, including wired and wireless components, is proposed, and the area of the base station that covers the power line carrier (PLC) line can be replaced by wireless components. Second, a scalable DDU set is built, which links the data flow and the planning decision variables, and the influence of the user’s willingness to participate in DR is considered. Meanwhile, the DDU set can be degenerated into a decision-independent uncertainty (DIU) set or a deterministic set by changing the model coefficients. Then, to solve the proposed model, a precise robust cuts method is presented with a detailed derivation. In this method, static robust cut constraints are adopted, whereby all information of the uncertainty set can be considered. Case studies show that the proposed model can effectively improve the economics and security of PTCPS communication path planning.

From the perspective of nonlinear dynamics and bifurcation theory, this paper analyzes the impact of time delay on small-signal stability region of doubly-fed induction generator (DFIG) grid-connected power system. Firstly, the differential-algebraic equation model of the system is established. It is theoretically demonstrated that time delay will affect the bifurcation behavior of the system, especially the degenerate Hopf bifurcation (DHB) under a specific time delay. Then, the time delay, the injected DFIG mechanical power, and the load reactive power are chosen as the bifurcation variables. The bifurcation diagram is obtained through bifurcation analysis, which can determine the multi-parameter small-signal stability boundary of the system. Finally, the impact of single and multiple time delays on the stability region is analyzed through the stability boundary. It is found that the DHB due to the time delay variation induces a hole effect in the system stability region. Moreover, increasing the time delay may also improve the system stability margin. The findings of this study have significant guiding implications for multi-time delay system parameter adjustment.

A power system is a strongly nonlinear dynamic system, and traditional small disturbance stability analysis cannot reflect the dynamic characteristics of the system under uncertain disturbances. This paper proposes a robust practical stability region (RPSR) partitioning method that considers uncertain disturbances to address the uncertainty of wind power injections and load volatility in wind power systems. First, a disturbance model of the wind turbine generator access system is constructed on the basis of perturbation theory to investigate the effects of uncertainty disturbances on the dynamic characteristics of the system. Second, through bifurcation analysis and limit cycle (L-cycle) tracking, a comprehensive bifurcation diagram that considers the variation trend of the L-cycle amplitude is drawn. Combined with the variation trend of the L-cycle, the RPSR of the system under uncertain disturbances is partitioned. Case studies of dual-machine system and multimachine system explore the new concept of the RPSR. Last, numerical simulations are used to verify the effectiveness of the analysis results and the proposed method.

Recognition and analytics at the edge enable utility companies to predict and prevent problems in real time. Clearing the voltage sag disturbance source by the positioning method is the most effective way to solve and improve the voltage sag. However, for different grid structures and fault types, the existing methods usually achieve a sag source location based on the single feature of monitoring data extraction. However, due to the effectiveness and applicability of the existing method features, this paper proposes a multidimensional feature of the voltage sag source positioning method of the matrix. Based on the analysis of the characteristics of the voltage sag event caused by the fault, this paper proposes a multidimensional feature matrix for voltage sag source location, based on the convolutional neural network to establish the mapping relationship between the feature matrix and the voltage sag position, thus achieving multiple points based on multiple points. The voltage sag source orientation is identified by the monitoring data. Finally, the voltage sag event caused by the short‐circuit fault is simulated in the IEEE14 node model, and the effectiveness of the proposed method is verified by simulation data. The simulation results show that the proposed method has higher accuracy than the traditional method, and the method can be applied to different grid structures and different types of faults.

Power definitions under nonsinusoidal conditions are an important premise for reactive power compensation and power quality control. In this paper, power definitions recommended by IEEE Std.1459-2010 and currents' physical components(CPC) theory are analyzed in the hybrid passive-active compensation system. Criteria for evaluating the effectiveness of these two methods is presented by theoretical analysis. And the rationality of this criteria is validated by simulations.