Research On Control System Of New Type Transformer With Controlled Reactor Function

In the power system, the power factor is a key indicator of power quality, therefore controlling the power factor to maintain a appropriate value can significantly improve the quality of power supply, at the same time the phenomenon of the DC bias in the transformer also affects the safe operation of the power grid, it can reduce the system voltage, make the system relay malfunction, etc. So it is also important to solve the problem of the DC bias.For solving these problems this paper proposes a new transformer which has the function of controllable reactor based on the magnetic integration technology. Measured the voltage and current of power grid by the detection circuit, and by synchronizing circuit to determine the power electronic devices and power grid to real-time work with the same frequency, then make the detected voltage and current signals by the modulation circuit into DSP28335.According to the instantaneous reactive power theory to calculate the reactive current, output the corresponding PWM waveform, after the drive circuit amplification, then control IGBT open and shut off. In this paper, two kinds of controlled reactor are applied, one is a magnetically controlled reactor based on material regulates magnetic saturation of iron core,the other is the controllable reactor based on the PWM control. Both of them can smooth continuous adjust inductance value, used in the reactive power compensation. In addition,the side yoke of the iron core can produce the contrary to the DC bias field current. Then the the DC magnetic bias phenomenon caused by HVDC and geomagnetic storm can be solved,the DC magnetic bias phenomenon can cause transformer neutral point grounding potential rise, the transformer core is saturated every half cycle. Make the transformer and reactor in one iron core, through the reasonable magnetic circuit design, make the reactor does not affect the normal work of the transformer, using magnetic integration technology can effectively reduce the volume of magnetic components and loss, economy of materials and so on. In this paper, some circuits such as the detection circuit and synchronous circuit are designed. And simulation the detection circuit, synchronous circuit by the proteus, check the correct of design,and use the Matlab, Simplorer, Ansoft, three simulation soft, to simulate three kinds of structures, and for reactive power compensation simulation is conducted and inhibition of dc bias.At last, through constructing the experimental circuit of new type of transformer with controllable reactor functions, in view of the structure scheme one, for transformer and reactor working alone and both of them working together experiment, and also make the inhibition of DC bias experiment, comparing the results of experiment before and after test, verify the idea the feasibility and correctness, lay the foundation for later research work.