High-voltage side reactive and harmonic low-voltage side plus transformer compensation system and method

Abstract

The invention provides a high-voltage side reactive and harmonic low-voltage side transformer compensation system and method. The system comprises a transformer, a high-voltage side current transformer, an intermediate conversion circuit and a low-voltage APF / SVG device, wherein the low-voltage APF / SVG device is connected to the low-voltage side of the transformer, the high-voltage side of the transformer is connected to a high-voltage power grid, the power supply current or load current of the high-voltage power grid is converted into a secondary current signal through the high-voltage side current transformer, and the secondary current signal is converted into a power supply side sampling signal or a load side sampling signal of the low-voltage APF / SVG device through the intermediate conversion circuit. Under the condition that software is not adjusted, the universal low-voltage APF or SVG can be applied to harmonic and reactive compensation of a medium-voltage power grid and a high-voltage power grid, so that the hardware cost is hardly increased, and even when the intermediate conversion circuit is installed in the universal low-voltage APF / SVG device, the hardware cost is not increased at all.

Description

technical field [0001] The invention relates to the field of active power filtering and reactive power compensation, in particular to a low voltage side transformer compensation system and method for reactive power and harmonics at the high voltage side. Background technique [0002] When the medium voltage transmission line has a long transmission distance, the transmission line has a large capacitance to the earth, so capacitive reactive power will be generated. This capacitive reactive power results in a lower power factor and therefore needs to be compensated. Compensating the capacitive reactive power of the medium-voltage grid can usually use a medium-voltage SVG (Static Var Generator), but compared with the capacitive reactive power of the transmission line that needs to be compensated, the capacity of the medium-voltage SVG is relatively large, so it is not suitable suitable for use. A suitable solution is to use low-voltage SVG and use a step-up transformer to con...

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Problems solved by technology

[0006] The disadvantage of the above method is that a large number of phase transformations are required, such as synchronous voltage phase transformation, device current phase transformation, load current phase transformation and reference current phase transformation

These transformations will take up a lot of DSP running time, resulting in the weakening of other functions of the software system or increasing the cost of using a DSP with a higher operating frequency

In addition, for low-voltage APF and SVG, the amount of compensation used in medium and high voltages only accounts for a small part of the total, and it is only a helpless choice to make a large number of software modifications to adapt to a small number of applications

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