Alternating power flow calculation method and device for light HVDC transmission system

Abstract

The invention provides an alternating tidal current computing method and device for a light high-voltage direct current transmission system; the alternating tidal current computing method comprises the following steps of: dividing the whole system into two parts of an alternating current subsystem and a direct current subsystem by using a busbar of an alternating current system as a dividing line, wherein the alternating current system is connected with a converter station; treating the converter station of the alternating current subsystem as an equivalent PQ or PV node on an alternating current node when the variable quantity of the operational state of the alternating current subsystem is solved; and modeling an alternating system as a constant voltage applied on the bus of the converter when an equation set of a direct current system is solved. The alternating tidal current computing device for the light high-voltage direct current transmission system comprises a data acquisition unit, a data transmitting unit and a data processing unit. The invention has the advantages of being simple and easy in implementation, being good in procedure generality, overcoming the disadvantages of bad timeliness, high error rate and the like and increasing the computation speed and correctness. The device adopts a double-port RAM (Random Access Memory) circuit so as to solve the problem of low data transmission speed; and a set of spare double-port RAM (Random Access Memory) is added for ensuring the correctness and reliability of the system operation.

Description

technical field [0001] The invention belongs to the field of power system power flow calculation, and in particular relates to a method and device for calculating alternate power flow of a light-duty high-voltage direct current transmission system. Background technique [0002] Power system power flow calculation and analysis is the most basic and important part of power system steady-state analysis, and it has great practical value in all aspects of power system. Operating status, such as voltage on each bus, power distribution in the network, power loss, etc. [0003] The light-duty HVDC transmission system is an AC-DC hybrid system. The task of power flow calculation is to obtain the voltage amplitudes of all nodes in the system through calculation according to the given load and power generation conditions of each node in the AC system, combined with the control mode of each converter. Value and phase angle, operation control parameters of each converter, DC voltage and...

AI Technical Summary

Problems solved by technology

The unified solution method is to combine the power flow equation of the AC system and the equation of the DC system, and obtain all the unknown variables in the AC system and the DC system. This method has good convergence characteristics, and the number of iterations required is the same as that of pure AC The calculation of the system is very close, but due to the addition of new control variables and equations, the Jacobian matrix of the simultaneous equations deteriorates, which brings difficulties to the application of sparse technology in solving the correction equations, and the AC and DC programs are inconvenient to interface, resulting in Programming is difficult, and the versatility of the program is not good; the alternating solution method solves the AC system power flow equation and the DC system equation separately, and iterates alternately until convergence. The AC and DC power flow program using the alternating algorithm has clear structure, simple programming, and Good versatility and other characteristics, but because the coupling between AC and DC systems is not considered, the convergence is poor and the calculation efficiency is low

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