Research On Model And Algorithm Of Reactive Power Loss From GIC Saturated Transformer Based On V/I-Curve

Geomagnetic storm interference is an important problem for the future power gird in China. The problem caused by saturated transformers when GIC presents. The reactive power loss from GIC saturated transformer increases, disturbing the normal operation of power grid. As the UHV and EHV is developing and power grid is scaling up, the threat of GIC reactive power fluctuation is brought to the forefront. To assess the risk, accurate computation is difficult for that all saturated transformers changes reactive power loss simultaneously. It’s applicable only for the model with parameters got easily and calculation carried out quickly. The researches in the past focus on accurate model for one transformer’s dc-bias effect simulation. The complicated models need huge computation. Systematic research specifics to reactive power loss computation from GIC saturated transformer is absent.This paper fistly describes the necessity of GIC saturated transformer reactive power loss model research. Then based on theory and test results, magnetization characteristic which is the input parameter of the model is analyzed. V-I curve is determined to be the chosen form, and its acquiring method is claborated. After analysis of influence factor and increase principle for reactive power loss, the method to calculate the quantitive value is established. Also the corresponding value of GIC is demarcated. These constitute the output parameters of the model. Next the main part of the model which is magnetic and electric circuit is build, base on the simplification of traditional transformer model. The simplification focuses on variable and solving process aiming at reducing computation amount and parameters needed. The transfomer model ends up with projection method based on ψ-i curve. Then the transformation model from input V-I curve to ψ-i curve has been designed. Test results of transformer verified the reliability of the transformation. At last, the algorithm is stated. With the parameters provided by transformer factory, such as saturated V-I curve and nameplate data, the algorithm is validated. The calculation results of reactive power loss from GIC saturated transformer are obtained.