Oscillation tracing method and device for power system comprising converter and synchronous machine

By performing order reduction and synchronous machine port admittance matrix analysis on the power network, the synchronous machine providing negative damping torque is identified as the oscillation source. This solves the problem of tracing the source of low-frequency oscillations caused by the lack of converter information in large-scale power systems, and achieves accurate tracing and suppression of low-frequency oscillations.

CN122361992APending Publication Date: 2026-07-10STATE GRID SHANDONG ELECTRIC POWER CO
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Patent Information

Application Number
CN202610347201.1
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-03-20
Publication Date
2026-07-10

AI Technical Summary

Technical Problem

Existing technologies struggle to accurately trace the source of low-frequency oscillations in large-scale power systems containing converters and synchronous machines when internal converter information is unavailable, resulting in an inability to effectively suppress low-frequency oscillations.

Method used

By reducing the order of the power network and establishing a linearized admittance matrix, and combining the port external admittance matrix and torque coefficient of the synchronous machine, the synchronous machine providing negative damping torque is identified as the oscillation source. The oscillation source is traced using a network order reduction module, an equipment admittance construction module, an external admittance construction module, an impedance torque calculation module, and an oscillation source identification module.

Benefits of technology

It can accurately identify low-frequency oscillation sources without requiring internal converter information, is applicable to converter systems with different control strategies, has good economic benefits and universality, and can provide theoretical guidance for low-frequency oscillation suppression.

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Abstract

The invention discloses an oscillation traceability method and device for a power system comprising a converter and a synchronous machine, and belongs to the technical field of power transmission and distribution of power systems, and the method comprises the steps: carrying out the order reduction of a power network, and constructing a linear admittance matrix; all power supply equipment port admittance matrixes including a converter and a synchronous machine under small disturbance are established; establishing a synchronous machine port external admittance matrix considering converter impedance embedding according to the port admittance models of the power supply equipment and the power network; the port impedance of each synchronous machine is obtained in sequence, and a damping torque model of each synchronous machine is established; and finding out the synchronous machine providing the negative damping torque according to the phase characteristics of the damping torque model, namely the low-frequency oscillation source of the system. According to the method, internal information of the converter is not needed, information isolation between different power supplies can be achieved, the method is suitable for converters of different control strategies, the physical significance is clear, theoretical guidance can be provided for oscillation suppression of a large-scale multi-machine power system, application can be embedded in power system analysis software, and the engineering significance is great.
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