The characteristic of photovoltaic power generation, which relies on the weather, is greatly affected by weather. The power generation will change with changes in light intensity, and there is randomness, which may lead to fluctuations in the frequency of the entire power grid system.
Taking the 4-megawatt surface photovoltaic power station in Dongjin Village, Huzhen Town, Longyou County, Quzhou City as an example, last year its average daily power generation was 3.28 hours, with an average daily power generation of 13700 kilowatt hours. When there is sufficient sunlight, photovoltaics are added to the grid, while when there is no sunlight, photovoltaics stop generating electricity and frequently start and shut down, causing some nodes in the grid to lose voltage support at certain times, resulting in harmonic components that affect the normal power supply of the grid and users.
Photovoltaic power generation is direct current. When connected to the grid, it is necessary to convert direct current into alternating current of the large grid, which requires the use of power electronic devices such as inverters. The switching action of inverters will generate harmonic voltage and current, further deteriorating the power quality of the grid.
In addition, the widespread application of electric vehicle charging stations, motors, power transformers, variable frequency fans and other equipment not only improves the quality of life and production efficiency, but also brings harmonic pollution, affecting the level of power grid quality.
The decline in power quality can lead to unstable operation of electrical equipment, affecting its normal use. At the same time, it can also cause a certain degree of loss to most equipment, reduce its service life, and even cause equipment failure and damage, thereby affecting the safe operation of the power system and electrical facilities. Taking Longyou in Quzhou as an example, the 110 kV Lantang substation is the main power supply for Longyou Industrial Park. There are multiple photovoltaic power generation enterprises and electronic component production enterprises with high requirements for power quality in the supply area. Power quality issues can easily cause losses to sensitive users and also have a certain impact on the production and daily electricity consumption of other nearby users.
In order to further improve the quality of power supply in the power grid and provide high-quality power supply services, State Grid Quzhou Power Supply Company, in collaboration with State Grid Zhejiang Electric Power Research Institute, has independently developed a new type of power system power quality optimization and governance device over a period of two years, and selected Lantang Substation for pilot based on regional characteristics.
Compared with traditional SVG (dynamic reactive power compensation device) and APF (active power filter), the new power system power quality optimization and governance device has stronger functionality, higher flexibility, and better adaptability Xu Qunwei, a member of the flexible technology team of State Grid Zhejiang Electric Power Research Institute, introduced that "especially in complex scenarios where interference source users and distributed photovoltaics are densely connected, the device has better technical and economic advantages.".

The new power system power quality optimization and governance device has expanded its functions. Compared to the single governance function of traditional SVG (dynamic reactive power compensation device) or APF (active power filter), the new device integrates multiple functions such as dynamic reactive power compensation, harmonic governance, and imbalance compensation. It can effectively solve problems such as three-phase imbalance, low power factor, and harmonic pollution, and users do not need to select and configure equipment one by one. In terms of usage, when faced with the coexistence of diverse governance needs, the new power system power quality optimization governance device can flexibly adjust the capacity allocation among the three functions according to actual needs, and has stronger adaptability. Since the operation of the Longyou Lantang substation in Quzhou, the harmonic voltage has decreased by 17% and the voltage imbalance has decreased by 87%, significantly improving the power supply quality of the Lantang substation supply area.
The feeling of electricity quality is most intuitive for electricity consuming enterprises. After the new power system power quality optimization and governance device was put into use, our company's paper-making equipment has been operating at high efficiency, greatly reducing the frequency of fluctuations and further improving our production efficiency The electrical responsible person of Zhejiang Weida Paper Industry Co., Ltd. gave this feedback.
The successful development and operation of a new type of power system power quality optimization and governance device has brought new avenues for enterprises, governments, and the energy industry to carry out power quality governance