Knowledge: Several mains problems that affect UPS operation

People generally think that the electricity we use is continuous and constant except for occasional power outages. As a public power grid, the municipal power system connects thousands of loads, some of which are sensitive, Capacitive, and switching power supplies, in turn, it will affect the power grid itself, deteriorate the power supply quality of the power grid or local power grid, and cause grid voltage waveform distortion or frequency drift. In addition, natural and man-made accidents, such as earthquakes, lightning strikes, power transmission and transformation system circuit breaking or short circuits, will endanger the normal power supply, thus affecting the normal operation of the load. These mains supply problems will lead to UPS power outages and other problems, so that people may mistakenly identify the UPS as a fault, rather than finding the real cause of the fault.

According to tests by power experts, the following problems often occur in the power grid that affect or damage computers, precision instruments, and upss:

1. Surge power surges): the output voltage valid value is higher than the rated value of 110%, and lasts for one or more cycles. The surge is mainly caused by the high pressure caused by sudden uninstallation of the power grid when a large electrical device connected to the power network is shut down.

2. high voltage Pulse high voltage spikes): refers to the voltage with a peak value of 6000 v and a duration of 10 ms from one thousandth second to 1/2 period. This is mainly caused by lightning strikes, arc discharge, static discharge, or switch operations on large electrical equipment.

3. transient overvoltage switching transients: refers to the pulse voltage with a peak voltage of up to 20000 V, but with a duration ranging from one second to one thousandth second. The main cause and possible damage are similar to high-voltage sharp pulses, but there are differences in the solution.

4. power sags: a low-voltage state in which the mains voltage valid value ranges from 80% to 85% of the rated value and lasts for one to several cycles. Such problems may occur when a large device is started, when a large motor is started, or when a large power transformer is connected.

5. Wire noise electrical line noise: RF interference (RFI), electromagnetic interference (EFI), and other high-frequency interference. The operation of the motor, the action of the relay, the operation of the motor controller, broadcast emission, microwave radiation, and electrical storms will cause line noise interference.

6. frequency offset frequency variation): the change of the mains frequency exceeds 3Hz. This is mainly caused by the unstable operation of emergency generators or the unstable frequency of power supply.

7. continuous low voltage brownout) indicates that the mains voltage valid value is lower than the rated value and lasts for a long time. The causes include startup and application of large equipment, Master power line switching, startup of large motor, and line overload.

If your mains supply has a similar problem, we recommend that you ask the power supply department to measure the grid frequency, waveform, voltage, and other parameters to confirm whether the mains supply has the problem.