Energy storage power station technology and business model inspection activity (changsha station) - September 9 - changsha

Polaris energy storage network: reactive power compensation full name reactive power compensation, its role is in the power system to adjust the power factor and power supply efficiency of the grid, improve the power supply environment. The photovoltaic + energy storage system cannot reduce the corresponding reactive power, resulting in a decrease in the power factor. When the power factor is below 0.9, a penalty will be imposed on the owner. Therefore, reactive power compensation is needed in photovoltaic + energy storage system to make the power factor not lower than 0.9.

 

Lin Yang new energy research institute WeChat public ID: linyang8666 author: oak lai, port lai

 

01 what is reactive power compensation

 

Reactive power compensation is the full name of reactive power compensation. Its function is to adjust the power factor and power supply efficiency of the power grid in the power system and improve the power supply environment. The common implementation is to install reactive power compensation device in the system. At present, SVG (dynamic reactive power compensation device) is a common reactive power compensation device in power system.

 

Why does pv + energy storage system need reactive power compensation?

 

With the rapid development of photovoltaic + energy storage system, the capacity that is incorporated into the power grid increases significantly each year, resulting in certain influence on the power grid after the system is connected to the power grid. Among them, the low power factor is the most prominent problem. Power factor is a parameter to measure the efficiency of electrical equipment, if the power factor does not meet the relevant regulations, there will be a corresponding penalty.

 

In the process of operation of electric equipment, besides active power, a certain amount of reactive power is needed. However, the addition of photovoltaic + energy storage system only reduces the active power obtained by the electric equipment from the power grid, but does not correspondingly reduce the reactive power, resulting in a decrease in the power factor. According to the power factor adjustment method (hereinafter referred to as the method), when the power factor is lower than 0.9, the owner will be fined. Therefore, reactive power compensation is needed in photovoltaic + energy storage system to make the power factor not lower than 0.9.

 

1. Webp (10). JPG

 

FIG. 1 application diagram of photovoltaic + energy storage system

 

03 case analysis

 

The following is an analysis of the application scheme of "peak cutting and valley filling" in a factory in jiangsu province. After the plant is equipped with a 2MW photovoltaic +4MWh energy storage system, the peak power consumption decreases from 9.2MW to 7.5MW, resulting in a power factor below 0.9, so reactive power compensation is needed to improve the power factor. The capacity of the reactive power compensation device is calculated as shown in the following table:

 

FIG. 2 calculation of reactive power compensation electricity

 

2. Webp (7). JPG

 

As can be seen from the figure, the maximum value of reactive power to be compensated is 823.35kVARh. Therefore, 900kVAR dynamic reactive power compensator (SVG) is needed to compensate the reactive power.

 

Compensation for reactive power

 

If the reactive power compensation equipment is not added, the power factor of the factory can be calculated as 0.89 according to the calculation method and provisions in the measures, and the penalty amount is 0.5% of the total annual electricity fee, about 157,000 yuan.

 

Although reactive power compensation is only a small aspect in system design, it affects the benefits of photovoltaic + energy storage system. Today, when the benefits of photovoltaic + energy storage system are too penny-wise, every factor affecting the benefits should be fully considered. Therefore, the problem of reactive power compensation cannot be ignored in the scheme design of photovoltaic + energy storage.