Full-pure embedded calculation method for alternating-current and direct-current power flow of power system

Abstract

The invention discloses a full-pure embedded calculation method for alternating-current and direct-current power flow of a power system. The method comprises the following steps: constructing a full-pure alternating-current power flow calculation model; constructing a full-pure control model under various control modes by considering different control modes of a converter station, and performing related calculation of the VSC converter station according to an equivalent model of the converter station in combination with the alternating-current network power flow result to obtain related data such as converter loss and active power of a direct-current node; determining a DC network node type according to an active control mode of the converter station, respectively constructing a full-pureequality equation for each DC node, forming a full-pure DC power flow calculation model, and carrying out DC network power flow calculation; updating the PCC active power of the AC system according tothe DC network power flow data, subtracting the PCC active power from a previous result of the value, returning to the initial step if the difference value is greater than a set threshold value, acquiring the overall power flow distribution of the AC-DC hybrid system if the difference value is less than the set threshold value, and ending the process.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a purely embedded calculation method for AC and DC power flows in power systems. Background technique [0002] With the development of electricity demand and large-scale grid integration of renewable energy, DC transmission technology has been greatly promoted. Its own technical and economic advantages are reflected in various fields, and it has great development prospects. [1-2] . At the same time, with the increase in the number of HVDC transmission projects and the increase in transmission capacity based on Voltage Source Converter (Voltage Source Converter, VSC), the AC-DC hybrid grid has become more and more complex. [3] , compared with the traditional power system, its operating characteristics have undergone tremendous changes, and the difficulty of accurately obtaining the power flow distribution of the power system has also greatly increased. [0003] Power system power fl...

AI Technical Summary

Problems solved by technology

[0004] Most of the existing AC and DC power flow calculation methods are based on the Newton-Raphson (N-R) iterative method. Due to the local convergence characteristics of N-R itself, it is necessary to provide an initial value close to the real solution, and the selection of the initial value It is often based on experience to guess the initial value of the trend and try again and again. This work is very cumbersome and takes up a lot of time

In addition, whether the power flow of the AC-DC system can converge to the correct solution depends largely on the selection of the initial value. If the initial value is not selected properly, the inner loop will not converge, and the outer loop will be affected, which will cause the overall flow of the AC-DC system to fail to converge. , leading to the inability to accurately obtain the power flow solution of the power system, affecting the normal development of power system planning, steady-state transient operation analysis, reliability assessment, etc.

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