The face of diverse and uncertain factors may have negative impact on power quality, in order to improve power quality, all aspects of power grid planning, power equipment configuration, voltage regulation measures should be fully deployed to prevent risks ahead of schedule, and timely investigation of hidden dangers . Found earlier: real-time online monitoring On October 20, Chongqing Electric Power Research Institute, through the on-line power quality monitoring system, monitored the excessive harmonic current of a power supply line in a certain factory and promptly notified the relevant departments for processing, thus avoiding the damage to the power equipment caused by the harmonic pollution of the power grid. There are many factors affecting power quality, mainly related to the structure of the power grid, load level, line faults, user load characteristics and so on. State Grid Corporation of China, "on the issuance of plans to promote the implementation of quality online monitoring system construction notice" requires that by the end of this year to complete the system master function development and interoperability with relevant business systems transformation to achieve grid frequency, grid voltage, power supply Voltage, reliability of power transmission system with voltage level of 220kV and above and the corresponding data of on-line reliability of power supply of high and medium voltage customers in key cities and on-line monitoring; before the end of 2014, 110 (66) kV and above Voltage level power transmission system reliability and all with high, medium voltage customer data acquisition and on-line monitoring; before the end of 2015, synchronous follow-up smart meter collection terminal to promote the deployment of work to achieve national grid low voltage customer reliability index data Automatic acquisition, to achieve the power quality from decentralized to centralized, from manual entry to automatically collect, engaged in statistical analysis to the online analysis of the management model changes and acquisition of the basic coverage. In Chongqing, the on-line power quality monitoring system has been put into operation in power supply enterprises in Jiangbei, South Bank and urban areas, realizing real-time monitoring of important 110kV substations, important customers and important lines. Electric Power Research Institute of Chongqing Electric Power Quality Inspection Lvzhi Sheng said: "Before working more passive, often after the failure to find the reason, and now has an online monitoring system that can detect anomalies in advance indicators to reduce the occurrence of the fault." Lvzhi Sheng said that prevention and detection of failure is the first step. After the fault occurs, the grid fault analysis is the key to improve the power quality. In this session, Chongqing Electric Power Research Institute explored a five-step power grid failure analysis mode of "prospecting, searching, building, imitation and nuclear". To investigate in detail the operation behavior before and after the failure, the relevant safety control devices and relay protection, etc. by means of field inspection of the fault site, exchange with substation and / or power plant attendants and inspection dispatch logs. Search, that is, collect the necessary information for failure analysis. Building, that is, based on the grid simulation laboratory, building an analysis model of fault recording data and a simulation model for fault inversion. The simulation model is used to invert the fault. Combined with the fault recorder data analysis model, the fault theory is used to deduce the evolution sequence of faults and relay protection actions, restores the fault process and deeply analyzes the cause of the fault. Nuclear, that is, by the professional and technical person in charge of primary and secondary organizations, the results of simulation analysis carried out a review to discuss the cause of the failure analysis is accurate. Better to transform: standard and reasonable grid upgrade In the recently held 77th International Electrotechnical Commission (IEC) Conference, SGCC introduced measures to deal with power quality challenges in particular, in addition to the existing IEC standards, in order to better adapt to the situation in China, the application of IEC standards established in China A series of Chinese national standards, from the three aspects of power generation, transmission and electricity to fully support the safe and stable operation of the power grid to ensure the quality of power supply. Li Yongtao said that at present, China GB / T 17626.X series of standards equivalent to the reference to IEC standards, provides for the provisions of the power quality parameters and power equipment on the quality of the power of the various parameters of the immunity, is an important standard in the field of power quality . Progress has been made in the standardization of power quality. In the meantime, all local power supply enterprises actively planned and constructed, upgraded and upgraded the power grid to ensure and enhance the power quality of power supply. It is understood that in recent days, State Grid Shandong Electric Power through the construction of low voltage power distribution network transformation, distribution network scale continues to expand, basically meet the load growth and power demand, 10 kV heavy load, overload lines and distribution ratio Have a significant decline. At the same time, with the transfer of load to each other, the ability to provide each other, Shandong Province, distribution network to withstand natural disasters and external damage capacity has been significantly enhanced. State Grid Zhejiang Electric Power in rural areas for the growth of electricity demand in some areas of the "low voltage" to carry out special comprehensive management, reliability of electricity as an important symbol of the power quality continues to meet the rural residents to improve living standards of electricity needs ...... Power grid construction and power supply reliability are closely related. Recalling the "Great Power Blackout" will find that the American Power Research Association has revealed after the power outage that after the power outage, the call for more power investment has been on an unprecedented rise and was clearly reflected in the stock market next day after power outage. When the United States Secretary of Energy said he was investing in upgrading the nation's power equipment, adopting new industry standards, and strengthening the safety factor of the system and equipment to prevent similar accidents from happening again.