Development trend of power quality control technology

Power quality control is a complex system engineering, which involves power system, power electronics, automatic control and other aspects. At present, the research on power quality control abroad is setting off a climax, including the expansion of applicable power theory, the establishment of power quality evaluation index system, the proposal of new power quality analysis method, and the design and implementation of power quality control device based on user power technology. Several well-known international companies have produced their own power quality regulators, such as Siemens SIPCON2S, GE's SSVR (static series voltage regulator), ABB's DVR, and Softswitching's DSC (dynamic sag corrector). The world's first DVR developed by Westinghouse for the American Electric Power Research Institute was put into industrial operation in August 1996; the small (1MJ~10MJ) low-temperature SMES of IGC and ASC in the United States has been commercialized, and Japan, Germany, France and Italy have also carried out in-depth research on low-temperature SMES. In general, my country's research on power quality has just started, and most of the research is limited to the scope of harmonic and reactive power compensation, which is still far behind foreign countries. Various power quality compensation devices such as APF, SVC, UPQC, DVR, etc. are still in the stage of theoretical and experimental research. Xi'an Jiaotong University has developed a 120kVA parallel active power filter, and the Institute of Electrical Engineering of the Chinese Academy of Sciences and the Department of Electrical Engineering of Tsinghua University have also developed a small SMES prototype. In combination with the current research status of power quality at home and abroad and the new requirements for power quality put forward by social development, power quality control technology should be studied and improved in the following three aspects:
a. Basic theoretical research: scientific definition of power quality evaluation indicators and reasonable calculation methods of various indicators, research on new analysis and control methods, and the possible impact of grid-connected operation of new power quality control devices on the system (including steady-state and dynamic performance), etc.
b. Actively adopt new technologies in other fields to bring new vitality to power quality control technology: Use digital control devices based on high-speed digital signal processors (DSP) to replace traditional power quality control devices controlled by analog quantities, use solid-state electronic switches to replace conventional high-voltage switches to achieve synchronous disconnection, use distributed clean energy such as fuel cells and micro-gas turbines to improve power supply reliability and power quality, the development of computer and communication technology makes it possible to remotely monitor power quality, and high-power, self-shutdown power electronic devices are combined with modern control technology to develop new power quality regulation devices. Superconducting power devices (SMES and SFCL (superconducting fault current limiter)) will also play an important role in improving power supply quality.
c. Vigorously develop user power technology (custom power): This is a technology that uses modern power electronics technology and control technology to achieve power quality control and provide users with power supply that meets user-specific requirements. DVR and DSTATCOM are typical representatives of user power technology controllers. User power technology and FACTS are essentially the same, the only difference is the rated electrical value. The former is applied to distribution networks, and the latter is applied to transmission networks. Therefore, user power technology can also be called FACTS technology for distribution networks (D2FACTS).