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The advent of novel power systems has given rise to a multitude of safety and stability concerns associated with the integration of emerging energy sources and power electronic equipment. The active support of the grid-forming control strategy represents an effective solution to the voltage and frequency stability issues associated with the weak damping and low inertia inherent to high-ratio new energy systems. Firstly, a static voltage stability index based on critical impedance is proposed for assessment of the static stability margin of a new energy grid-connected system, based on the static voltage stability theory of a traditional single-unit single-load system. Secondly, an analysis is conducted of the control principle of the grid-forming control converter and its impedance characteristics. In conclusion, a method for enhancing the static voltage stability margin of grid-connected new energy stations through parameter control of grid-forming converters is presented. The simulation verification of the single-feed and multi-feed systems demonstrates the efficacy and accuracy of the methodology presented in this study.

As the typical provincial transmission power grid,Jiangsu power grid is faced with the pressures and challenges induced from system-integration of rapid developments of renewable energy during the energy transition period,which needs to be upgraded in "source-network-load-storage" and other aspects. Through the analysis of energy development from load,power supply,grid structure in Jiangsu,challenges faced by Jiangsu power grid such as insufficient transfer abilities of important transmission sections are put forward. Considering the large-scale integrated renewable energy and structure characteristics of Jiangsu transmission power grid,transmission-capacity demands of the Yangtze-river-crossing section during the "14th Five-Year Plan" and future are emphatically analyzed. Afterwards embedded DC transmission technology that both the transmission-and receiving-ends are located in Jiangsu AC network and distributed on both sides of the Yangtze River are proposed. Comparing with the traditional long-distance and high-capacity DC transmission technology constructed under the interconnection mode,the embedded DC transmission technology proposed in this paper usually uses the existing overhead transmission lines or existing/reserved AC cable channels to construct the AC-DC hybrid power grid in Jiangsu,greatly improving transmission capacities of important sections with limited transmission corridor spaces and power supply potential abilities of the existing power system to satisfy the development demands of Jiangsu power system.

With the increasing penetration of distributed energy in the distribution network, it is urgent to study how to ensure the stable and reliable operation of the power grid under fault conditions. To solve this problem, this study proposes a method for partitioning distribution network islands and reconstructing faults considering the Conditional Value at Risk (CVaR). This method aims to enhance the resilience of the distribution network and the recovery capability of critical loads. Initially, a partitioning model for distribution network islands based on depth-first and breadth-first search algorithms was constructed. Building upon this partitioning, a fault reconstruction method for distribution networks that considers CVaR was developed. This method utilizes CVaR theory to transform costs and quantifies the risk that the uncertainty of distributed energy resources poses to distribution network reconstruction strategies. Finally, the effectiveness of the proposed method is demonstrated using an improved IEEE 33-node system, generating typical fault scenarios. [ABSTRACT FROM AUTHOR]

This paper proposes a design method for an additional damping reduced-order controller based on the projective control theorem. Improvements are made to the projective theorem to achieve additional damping control through Controllable-Line-Commutated Converter (CLCC)-based High Voltage Direct Current (HVDC), which suppresses low-frequency oscillations. Using small disturbance identification techniques, the system's linear model is first identified, and the state feedback control law of the system is then determined using the state-space pole assignment control method. Then, by retaining the dominant oscillation modes of the closed-loop system through the improved projective theorem, the state feedback is converted into output feedback. Ultimately, the sixth-order state feedback controller is reduced to a second-order one and applied in the CLCC HVDC additional damping strategy to suppress low-frequency oscillations. Simulation results based on the electromagnetic transient simulation software PSCAD demonstrate that the designed CLCC HVDC additional damping reduced-order projective control exhibits good suppression performance, strong robustness, and low order, which are of significant importance for engineering practice. [ABSTRACT FROM AUTHOR]