Power flow calculation method for bipolar flexible direct current transmission system

Abstract

The invention discloses a power flow calculation method for a bipolar flexible direct current transmission system. The method comprises the steps of giving an active power initial value to a positiveelectrode, performing power flow calculation on a positive network, updating a negative electrode node active power initial value according to the calculation result, performing power flow calculationon a negative network, updating each node active power of the positive electrode according to negative active power obtained by the power flow calculation, and performing repeated iterative updatinguntil a voltage correction amount of positive and negative nodes reaches a convergence condition. The method has universality for different multi-end DC coordinated control strategies and DC networkswith different topological structures for the positive and negative electrodes, the power flow distribution of a true double-electrode system can be truly and accurately reflected. The method is basedon a node current relationship and is not sensitive to the selection of an initial voltage value, the same power flow calculation accuracy can be achieved with less iteration, and the method is moresuitable for the power flow calculation of a multi-end flexible DC network system in engineering.

Description

technical field [0001] The invention belongs to the field of flexible direct current transmission, and relates to a power flow calculation method of a bipolar flexible direct current transmission system. Background technique [0002] With the continuous development of renewable energy and the needs of current grid technology upgrades, the future development direction of flexible DC grids will focus on large-scale wind power transmission, regional grid interconnection, and power transmission to urban load centers. The flexible direct current transmission system will present the following characteristics: [0003] (1) The flexible DC transmission system is developing towards a higher voltage level and larger transmission capacity, and the flexible and reliable true bipolar transmission system has been developed and applied, and the operation mode of the power grid is more complicated; (2) The voltage source converter is conducive to the formation of parallel type multi-termin...

AI Technical Summary

Problems solved by technology

Due to the current correlation between poles, the power flow calculation method for unipolar networks cannot be directly applied to true bipolar systems

The current power flow algorithm has its limitations. It is only suitable for the power flow calculation of unipolar networks or symmetrical bipolar networks. It can only deal with a limited number of control methods, such as pure active control and simple droop control methods. Bipolar DC transmission system, which obviously cannot meet the needs of the rapidly developing DC grid

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