I. DC System Maintenance

1) Regularly clean the internal dust of high-frequency switching power modules;

2) Regularly clean the dust inside the DC panel;

3) Perform a discharge test with actual load on the battery once a year. The discharge current should remain stable, discharging about 30% of the rated capacity (discharge at 0.1C for 3 hours). Measure the voltage of individual cells, battery groups, discharge current, and temperature every hour during discharge. After discharge, perform equalizing charging and then switch to floating charging. 

4) Measure the voltage of individual battery cells and terminal voltage once a month, check for abnormal deformation or overheating, and maintain complete operation records.

5) Check the connection wires once a year for firmness, corrosion, or looseness. Tighten them to the specified torque, and replace corroded wires promptly;

6) Do not arbitrarily add or remove individual battery loads within the battery group, as this will cause imbalance in individual battery capacities and uneven charging, reducing battery life.

7) Common Failures and Solutions 

(1) Abnormal battery casing: Causes include excessive charging current, individual battery charging voltage exceeding 2.4V, internal short circuits or partial discharges, excessive temperature rise, or valve failure. Solution: Reduce charging current, lower charging voltage, and check whether the safety valve is blocked. 

(2) During operation, the floating charging voltage is normal, but the voltage quickly drops to the termination voltage upon discharge. The cause is internal battery dehydration or electrolyte degradation. Notify the manufacturer to replace the battery.

II. Emergency Handling Principles

A. The basic principle of emergency handling for power system failures is to maintain uninterrupted DC power supply for the system.

B. Major failures in power systems that threaten communication safety or cause communication interruptions include: irreparable damage to AC circuits, short circuits in DC loads or DC distribution, complete failure of rectifier modules, shutdown accidents caused by uncontrolled monitoring modules, and module lockout due to DC output overvoltage.

1) Emergency Handling of DC Distribution

(1) Local load short circuit: Disconnect the damaged load's DC circuit breaker or separate the feeder fuse. (2) Distribution short circuit: Short circuit faults in DC distribution caused by human errors (e.g., operator negligence) or natural factors (e.g., earthquakes) directly affect the safety of the DC system. After a fault occurs, the following steps are generally taken: cut off AC power supply; forcibly isolate the battery from the system; use the battery or rectifier module to directly supply power to the load.

2) Emergency Handling of Monitoring System Failures: If a monitoring system failure affects DC power supply safety, simply turn off the monitoring module. However, pay attention to battery management and maintenance during this time.

3) Emergency Handling of Module Failures

(1) Internal short circuit of the module: The module will automatically exit the system in case of an internal short circuit. (2) Partial module damage: If some modules are damaged, as long as the remaining intact modules can meet the load power requirements, turn off the AC power of the damaged modules. (3) Module output overvoltage: If the load current is lower than the capacity of a single module, overvoltage from one module will cause system overvoltage, triggering overvoltage protection for all modules, which cannot recover automatically. Solution: Turn off the AC switches of all modules, then turn them on one by one. If overvoltage protection occurs again when a specific module is turned on, turn off that module and turn on the others. The system will then resume normal operation.