1、 Voltage sag and drop problem

The inevitability of power grid failures in modern power grids and the vulnerability of power load immunity have increased the demand for high-quality and reliable power supply. For power users, voltage sag (also internationally recognized) is one of the most serious problems. The voltage sag caused by short circuit due to lightning, rainstorm, strong wind, construction and personnel misoperation is enough to affect the normal operation of sensitive equipment.

2、 The most common reasons for voltage sag and high voltage are as follows:

1) Voltage sag caused by fault current: When a short circuit fault occurs in the transmission or distribution network, the current increases sharply, resulting in a voltage drop at the common voltage connection point. At the same time, the voltage drop spreads along the power grid, causing interference to a large number of users;

2) Induction motor startup causes voltage sag: When an induction motor starts at full voltage, the voltage value that needs to be drawn from the system is 5-10 times that of full load operation. This large current flowing through the system impedance can cause voltage drop.

3) Lightning strikes, voltage dips caused by lightning strikes, insulator flashover caused by lightning strikes, and line to ground discharge are the main causes of voltage drops in system lines. In rainy seasons or areas with frequent thunderstorms, equipment exposed to the open air is easily affected by lightning interference.

4) Voltage fluctuations caused by low or high power factor can result in voltage losses on the line due to reactive power in the system, which is the reason why capacitive reactive power raises the supply voltage.

5) Unpredictable accidental events: road construction, traffic accidents, human error, etc.

3、 Industry standard requirements for voltage sag and drop

Voltage sag  

The IEEE standard and national standard "Voltage sag and short interruption of power quality" (GB/T30137-2013) define voltage sag as the phenomenon in which the root mean square value of the power frequency voltage at a certain point in the power system suddenly drops to 0.1p.u.~0.9p.u. and returns to normal after a brief duration of 10ms~1min.

Short term interruption

The phenomenon where the root mean square value of the power frequency voltage at a certain point in the power system suddenly drops to 0.1 p.u. and returns to normal after a brief duration of 10 ms to 1 min.

4、 Performance characteristics of DNVV products

DSP fully digital control, all power conversion links including rectification, inversion, charging, and discharging are digitally controlled;

System level single board level device level comprehensive protection, ultimate reliability, and stronger environmental adaptability;

Large 10 inch LCD touch screen display, color graphic display, easy to operate, user-friendly human-machine interface;

Intelligent system self diagnosis solution, rich fault records, and large capacity historical record storage space;

The maximum capacity supports 2MW, making it the best choice for uninterrupted power supply in ultra large data centers

5、 Application scenarios of DNVV products

1. Semiconductor industry (chip manufacturing, testing, and packaging)

2. New energy industry (solar polycrystalline silicon, monocrystalline silicon pulling silicon, battery testing, aging and packaging, etc.)

3. Medical device industry (medical testing equipment, radiotherapy and chemotherapy equipment, liquid phase analyzer, etc.)

4. Automotive manufacturing industry (automatic welding, painting, paint baking, etc.)

5. Food and beverage industry (food baking, packaging, canning, bottle making machines, etc.)

6. Petrochemical industry (refueling machines, refineries, kowtow machines, chemical plants, etc.)

7. Textile industry (screen printing machines, winding machines, winches, etc.)

8. Intelligent factory industry

6、 DNVV product working principle diagram

DNVV product working principle diagram

7、 Characteristics of DNVV technology