1.industry background

With the increase of China's photovoltaic installed capacity year by year, and the comprehensive development of the photovoltaic pilot work in the whole county, the distributed photovoltaic grid-connected penetration rate has increased rapidly, and the impact of high permeability on the power quality of the distribution network has become increasingly prominent. After distributed photovoltaic is connected to the grid, the power factor of power enterprises is reduced, which is assessed by the grid, and the enthusiasm of power enterprises to use photovoltaic power generation is affected. Solve the problem of reducing the power factor after the grid connection of distributed photovoltaic and meet the requirements of the grid, which can improve the enthusiasm of power enterprises to build and use photovoltaic.

2.demand analysis

(1)The causes of reactive power in electricity enterprises

Most of the power loads, such as motors and transformers, are inductive loads, which will produce a certain amount of reactive power during the operation of the equipment. The power distribution system of power enterprises will be equipped with a certain capacitor cabinet for reactive power compensation to improve the power factor of users.

(2)Influence of distributed photovoltaic access on user power factor

The typical grid-connected mode of photovoltaic power generation has three kinds: "spontaneous self-use, residual electricity online", "all self-use" and "full Internet access". "Self-use, surplus power online" and "all self-use" modes are photovoltaic power generation through the inverter to the grid-connected cabinet access to the original distribution facilities on the user side, and the user is provided by the grid when the power is insufficient; The "full access to the Internet" mode is that photovoltaic power generation is connected to the public grid by the inverter, which has nothing to do with the user's electricity consumption.

Distributed photovoltaic power generation access to the user side, the power generation metering meter is set up at the parallel point for billing compensation, and the two-way gateway power metering meter is set up at the property rights demarcation point between the user and the grid for the user's Internet access and electricity and electricity tariff settlement. "Self-use, surplus power online" and "all self-use" mode distributed photovoltaic power generation is connected to the user side, and the active power required by the user load is jointly provided by the grid and photovoltaic power generation. By setting the inverter, the photovoltaic power generation gives priority to the load power supply, and the shortage is provided by the grid. The reactive power required by the user's load is jointly provided by the power grid, SVG and photovoltaic power generation, because the power factor of the photovoltaic power generation inverter is basically set above 0.98, and the power factor is high, it can be considered that the photovoltaic inverter only outputs pure active power, and the reactive power required by the load is basically provided by the power grid and SVG.

Due to the existence of photovoltaic power generation, enterprise factory electricity consumption priority to use photovoltaic power generation. When the distributed photovoltaic power generation is large, the user load power consumption is small, resulting in a low power factor; There will even be photovoltaic power generation can not all be absorbed by the load, photovoltaic power generation will send active power to the grid, that is, generate on-grid electricity, at this time the network electricity is very small, the power factor will be reduced, there will be a power factor is not up to standard, for the user needs to bear part of the monthly force adjustment electricity.

(3)compensation method

Spontaneous self-use

By replacing the traditional reactive power compensation device of the capacitor cabinet with photovoltaic special SVG, the SVG is fully used for compensation and the power factor is improved. The scheme has the advantages of low cost, convenient connection, strong replaceable and good effect.

Spontaneous self-use, surplus electricity online

In the case that the photovoltaic power generation can be fully absorbed by the load, the processing scheme is the same as the "spontaneous self-use" mode; FGISVG can perform reactive power compensation in the second and third quadrants when surplus power is connected to the Internet. At the same time, FGISVG can set different SVG operating modes under different conditions of power generation and power consumption, so as to meet the changes in various operating conditions and working condition switching process and achieve the purpose of improving power factor.

3.FGI Distributed photovoltaic solutions

In view of the randomness, volatility, intermittency, low power factor, voltage fluctuation and other power quality problems of distributed photovoltaic power generation, FGI combined with application experience, launched a new generation of high power density SVG.

The new generation of SVG has the following advantages:

Using the new structure design, the product volume is further reduced, which greatly saves the land resources of the enterprise.

With time-sharing control automatic switching function, can automatically switch the operating mode and set the target according to the setting, compensation is more accurate.

Multi-machine coordination control function, can realize the coordinated control of multiple devices, flexible layout scheme.

Once launched, FGI distributed photovoltaic SVG solution quickly won a large number of orders with excellent product performance and excellent product quality, and won unanimous praise from customers. At present, the company's high-voltage SVG shipments have increased greatly, and the orders show the trend of increasing the capacity of a single unit and increasing the penetration rate of distributed small capacity. We are optimistic about the application prospects of SVG in the new energy industry, FGI will continue to uphold the original intention, focus on the research and development and application of power electronic equipment, provide more users with better products and services, and practice the corporate vision of "saving energy and serving society".

4.Typical case

Hefei Continental Horse Tyre Photovoltaic Project