Study On Reactive Power Compensation ,harmonic Elimination And Energy Conservation In Distribution System

With the wide spread of equipments made of the power electronics, and the digital control equipments based on computers and networks, the reactive power and harmonic pollution has bring heavy harm to the power system and power customers. Power System FACTS Technology Research & Developing Center of Shanghai Jiaotong University and Shanghai Jiulong Electric Power Science & Technology Co. Ltd. take the project from Shanghai Power Company, developing the integrated equipment with dynamic reactive power compensator and active power filter. The integrated equipment has the function of dynamic reactive power compensation and harmonic current elimination, and it is running successfully at lower side of 4# transformer in Huijingyuan power station of Shanghai.In section 2, the structure of main circuit of the integrated equipment and parameters are designed in detail, serveral protection method is also proposed to protect the device and the system. In section 3, the study is focused on the detection of reactive power current and control strategy. Because of the shortcoming of hysteresis tracking and triangular modulating tracking, the paper proposes a robust deadbeat control triangular modulating method to control the current. This method not only possesses very fast response, but also is robust to parameter changes, also the random or periodic noise. The strategy is also applicable to the current tracking in unbalanced systems. This characteristic is especially important in the power distribution system operation. Moreover, a novel phase-locked loop (PLL) is proposed, which can accurately obtain the phase of fundamental frequency voltage.In section 4, the scheme of integrated equipment controller is introduced in detail. In section 5, also akey of this paper, the testing results both in lab and field opearation are analysed in detail, the export report indicated that each target has been achieved the anticipated demand. In section 6, the value of energy conservation is evaluated. It's revealed that the proposed scheme of the device can significantly improve the power quality of the distribution system, and the harmonic injection to the utility grid can be within the limit of IEEE 519-1992 standard.