Practical Improvements On Load Flow Algorithms

The on-line load flow calculation is in the core position in the energy management system analysis software.It is not the basic function of the analysis software but also the basis of other funtions.Based on the engineering practice,in order to improve the calculation speed and precision,three practical improvements are advanced in the field of on-line load flow calculation in the paper:(1)In order to improve the speed of load flow calculation,we propose a modified method which is using different methods to deal with different type of nodes.(2)In the practical system,there is voltage difference in the coordinate bus.In order to improve the calculation precision,a model which is using small impedance branch instead of zero impedance branch as breaker which connects two buses is advanced and the impedance calculation method is also presented.(3)It is found that using Gauss-Seidel method twice and then using Newton-Raphson method can solve the convergence problem in the process of the load flow method being applied to dealing with the case of the small impedance branches.After apllied the improvements to DingXi District grid,it is proved that the method is easy and of great credibility and validity.It can be used for reference in the practical projects.