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Simplified Representation of Kessel/Glawitsch's Method

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This paper presents a simplified version of the original method proposed by Kessel/Glawitsch. Notably, the approach utilizes elements from the admittance matrix instead of the nodal impedance matrix, eliminating the need to invert the load portion of the admittance matrix. The calculation of the equivalent load (Sj+) considers power flows from branches connected to the load node, rather than nodal loads. Admittance matrix elements are determined at the beginning of each iteration and remain unchanged throughout the process. Voltage magnitudes and angles are adopted from the Continuation Power Flow (CPF) in each iteration. While Bus Voltage Stability Indices assess transmission bus voltage stability, they may not reveal the system's vulnerability characteristics related to potential voltage issues. In contrast, Node-Index methods provide easily interpretable stability indicators, reaching 1 at the stability limit, with values less than 1 characterizing a stable system. The proposed index, based on this refined Kessel/Glawitsch method, demonstrates superior early warning capabilities. It surpasses the critical point earlier in iterations compared to the original method, offering a practical and efficient approach for proactive issue identification and real-time monitoring in power system stability assessment.
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Node Index; Voltage Stability; Admittance Matrix Elements; Injected Reactive Power; Simplified Variation; Continuation Power Flow

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