Research On High-voltage Large-capacity Magnetic-controlled Switch Reactive Power Compensation Device

With the continuous development of industry in our country, the influence of power quality from the loads of industrial and mining enterprises is getting more and more attention. Industrial electricity includes a lot of inductance fluctuation load, which needs consume a large amount of reactive power. Therefore, applying dynamic reactive power compensation to these electrical loads has great significance for grid voltage and power quality. Besides, new energy power has the characteristic of non-constant load, harmonic generation and the demand for reactive power. With the rapid development and application of new energy sources such as solar and wind energy, new energy power generation has a great demand for dynamic reactive power compensation.In the field of 35 k V high voltage power distribution, both traditional SVC and novel SVG compensation equipment need to connect multiple switching devices in series. The quantity of the series connection can even be more than 40, which has effect on the reliability of the equipment. In order to solve the above problems, the thesis designs a novel dynamic reactive power device based on the model of multiple-winding transformer. The novel device connects the thyristor and multiple-winding transformer as a switch assembly, which is called Magnetic-control Switch, to switch the capacitor. The novel reactive power compensation mode not only satisfies the directive compensation under high voltage, but also realizes high-capacity compensation with a single device.The thesis detailedly introduces compensation load design, hardware structure and control system of the Magnetic-control Switch reactive power compensation device. The programmable logic controller, as the core of the control system, can make the logical judgment to sampled signal, guard signal, running conditions and so on. Then the programmable logic controller can give control orders to make the device operate automatically. In order to test and verify the design, the thesis has two steps, which are simulation verification and prototype experiment. The simulation verification part uses EMTDC/PSCAD electromagnetic transient simulation software to build circuit, and researches on the issue of damping resistance and thyristor trigger. On this basis, a 35kV-2100 kVar prototype is developed. Under the voltage of 35 kV, the experiments of no-load closing, turn on and off the compensation switch have been done repeatedly. The experiment results show the device has advantages of simple construction, operation reliably, short and smooth transient process and no harmonic generation, etc.