Operation and maintenance of DC power systems

1. The important role of DC power supply system

DC power equipment is the power plant of the power system, as well as very important control, power supply and signals in some substations. The DC power system plays a very important role in the operation of the equipment.

With the continuous development of power supply technology and the continuous improvement of substation automation, there are many important data that need to be stored and processed safely and reliably. Various electrical equipment, such as relay protection, carrier communication, and accident lighting, are inseparable from the work. DC power supply. In the event of a power outage, we will use the DC power provided by the DC power system to provide working equipment, so the DC power system is compared to the heart of a substation or power station.

2. Selection of voltage level of DC system

110V system: For the control load, the general current is small, 110V should be used. Especially in the medium and small substation, there is no motor load, plus the current circuit breakers are using hydraulic or spring operating mechanism, the closing current is only about 2A~5A, the power supply distance is short, mainly the control load, more conditions to use 110V.

220V system: The power of the power load is generally large, the power supply distance is long, the cable cross section is large when 110V voltage is used, and the investment is increased, the use of 220V is better.

3. Several points that should be paid attention to in the operation and maintenance of DC system:

① Key monitoring of DC equipment operation:

A. Monitoring of various voltages, ammeters and some important operating parameters. For example, the value of AC input voltage, battery voltage, DC bus voltage, charging device output voltage, etc., should pay attention to whether it is correct.

B. Monitoring of various signal alarm lights. Check whether the "Running" and "alarm" indicators of various devices are normal.

C. Monitoring of insulation status. Pay attention to the insulation status of the DC positive and negative bus bars to the ground. If there is ground, find and handle it as soon as possible.

② Key monitoring contents in the operation of the battery:

A. Single voltage value of the battery;

B. Terminal voltage of the battery pack;

C. The size and change of floating charging stream;

D. Whether the connecting piece is loose or corroded; Shell deformation and leakage; There is no acid fog and alkali around the pole and safety valve;

E. Temperature of the battery room.

4. Check specific equipment

① Inspection of DC cabinet

Check the meter needle and signal light of the DC charging cabinet to see if there are any abnormalities. If there are any abnormalities, repair them in time.Check whether the switches controlled by the equipment are in normal condition;

② Inspection of DC battery

Check randomly or one by one and test the battery voltage and specific gravity. Test whether the battery's discharge performance is intact.

③ Inspection of DC power patrol battery

Check and measure the indoor temperature and provide appropriate ventilation facilities. Check whether the indoor lighting and other accompanying equipment are in good condition, and any problems should be solved promptly.

④ Inspection of DC power charging equipment

Check whether the DC panel module and rectifier transformer are operating normally and whether they are too hot. If this happens, replace them immediately.