Method for judging transient state stability of alternating-current and direct-current hybrid power system containing flexible direct current

Abstract

The invention provides a method for judging the transient state stability of an alternating-current and direct-current hybrid power system containing flexible direct current. The method comprises thefollowing steps: establishing an alternating-current and direct-current hybrid power system mathematical model considering the dynamic response of a direct-current circuit and the transient state response of a voltage source converter; based on the alternating-current and direct-current hybrid power system mathematical model, constructing an alternating current and direct current hybrid power system transient state energy function containing flexible direct current under a structure reservation model, and calculating the initial state energy value of the system after a fault according to the transient state energy function; calculating the critical energy value of the system by using an iterative potential energy boundary surface method; and judging the transient state stability of the alternating-current and direct-current hybrid power system containing the flexible direct current according to the initial state energy value of the system after the fault and the critical energy value of the system. According to the method, the stability of the system can be quantitatively judged in real time through the energy-function-based transient state stability analysis of the alternating-current and direct-current hybrid system containing flexible direct current power transmission.

Description

technical field [0001] The invention relates to the technical field of media communication, in particular to a method for judging the transient stability of an AC / DC hybrid power system with flexible DC. Background technique [0002] Voltage Source Converter High Voltage Direct Current (VSC-HVDC) based on Voltage Source Converter is suitable for both small-capacity power transmission and large-capacity power transmission. VSC-HVDC technology is widely used in long-distance large-capacity power transmission, asynchronous networking and other fields. The energy imbalance caused by the transient action of the switch has a more serious impact on the transient stability of the system. In order to avoid the safety and stability risk of the AC-DC hybrid power system due to the VSC-HVDC transient commutation process, it is of great significance to study the transient stability assessment of the two-zone AC-DC hybrid interconnection system with flexible DC. [0003] The traditional ...

AI Technical Summary

Problems solved by technology

At present, the application of the direct method in the AC / DC hybrid power system is still in its infancy, and the research on the construction of the energy function of the AC / DC hybrid power system is limited. power load, so that the energy function of the AC-DC hybrid system can be equivalently represented by the energy function of the AC system. The DC line model constructed by this method is too simplified; there are also literatures that deduce the energy functions of the DC system and the AC system. The weighted and defined as the TEF of the AC-DC hybrid power system, this method ignores the dynamic problems of the DC line; the Padiyar method ignores the loss of the DC line, and the TEF analytical expression of the DC line can be obtained; some literatures propose a method that considers the traditional DC transmission line Transient energy function of a dynamic AC / DC hybrid power system structure-preserving model in which the DC transmission line is modeled in detail as an equivalent dynamic load affected by both the converter bus port voltage and the DC line current

The above method has studied and evolved the construction of the energy function of the traditional DC line, but the construction and research of the energy function of the flexible direct current (VSC-HVDC) is not yet perfect, and needs further research

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