Research And Application Of The Key Technology Of 500kV Static Var Compensation Transformer

The static var compensation transformer is a special voltage transformer, which is applied to the SVC system. The high-voltage side is directly connected to the power grid system and the low-voltage side with the reactive power compensation device. Due to the particularity application, the SVC special transformer performance requirements are different from the conventional power transformer. During the operation of the power electronic devices, a large number of harmonics will be engendered during the operation of SVC, which will lead to the reduction of the performance of the transformer. At the same time, due to the internal components of the SVC trigger, will produce a larger DC current, this part of the DC current will also enter the transformer inside, resulting in transformer core flux saturation. Because the SVC is mainly used for reactive power compensation, the load is transforming between capacitive and inductive, according to the characteristics of the transformer, the load characteristic changes will cause changes in the transformer outlet voltage, resulting in over-voltage. In view of the characteristic of SVC operation, we must consider the influence when designing the special transformer for 500kV Static Var Compensation. In the design phase, we should take certain measures to increase the loss, over voltage, temperature rise which caused by the harmonic, DC component, and load characteristic variation.Through the analogue simulation of the effect on SVC transformer caused by the DC component and the overvoltage and the calculation of harmonic loss, determine the electrical design method of a typical case of 500kV Static Var Compensation transformer, determine the calculation method of SVC special transformer related loss and short-time temperature rise and the loss of life the estimated rate of transformer. And according to the theoretical basis and previous practical experience, manufacture a typical 500kV Static Var Compensation transformer. In the process of manufacturing SVC special transformer combined with software calculation and simulation theory, considering the particularity of structure, in order to reduce the influence factors of load characteristics of harmonic components, DC component, special for transformer, and test on special transformer prototype, the test results fully qualified. Through the study, master the key technology of the 500kV Static Var Compensation special transformer, and hope to be popularized and applied in the following project. This paper provides a theoretical support for the feasibility of domestic SVC special transformer directly linked to the network access system, and provides a theoretical basis and design experience for the subsequent production of Static Var Compensation special transformer.