Flexible DC convertor station small interference impedance equivalence method

Abstract

The invention discloses a flexible DC convertor station small interference impedance equivalence method. In small interference analysis of a convertor station at one end of a flexible DC power grid, small interference impedance equivalence needs to be carried out on the rest parts; a flexible DC convertor station control system is complex; and when the small interference impedance equivalence is carried out thereon, multiple factors need to be taken into consideration. The equivalence mathematic model, taking both operating conditions of a primary system and multiple parameters of local control and coordinated control systems into consideration, has higher accuracy, and realizes balance between rapidity and accuracy of small interference analysis.

Description

technical field [0001] The invention relates to an equivalent method for small-disturbance impedance in small-disturbance stability analysis of a flexible DC power grid, in particular to an equivalent method for small-disturbance impedance of a flexible DC converter station. Background technique [0002] Voltage stability is an important indicator for the safe and stable operation of the AC grid. Compared with the AC grid, the flexible DC grid is usually connected to more power electronic equipment, such as converters, DC transformers, etc. The resistance of these power electronic equipment to voltage fluctuations Ability is usually not high. Therefore, it is more important to maintain the voltage stability of the flexible DC grid. [0003] The static stability analysis of the flexible DC system mainly adopts the small disturbance analysis method at present. Some existing small-disturbance stability analysis methods for multi-terminal flexible DC systems analyze the eigenv...

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Problems solved by technology

Some existing small-disturbance stability analysis methods for multi-terminal flexible DC systems analyze the eigenvalues ​​of the system characteristic equation matrix, and when the system scale increases, the size of the characteristic equation matrix will also increase, and when the system structure or parameters When changing, it is necessary to recalculate the system characteristic equation of the whole network, and the calculation amount is too large, which has a serious impact on the solution speed

Other small disturbance analysis methods divide the converter station with local control into voltage source and current source types according to the different components (capacitance or inductance) at the outlet of the converter connected to the DC grid, and further simplify it into non-ideal Voltage source or current source, these methods are too simplistic and cannot guarantee accuracy

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