Communication DC power supply DC distribution part
The DC distribution section distributes the DC voltage output by the rectifier, one for charging the battery pack and the other for supplying power to communication equipment and other DC users. The DC distribution part determines the final allocation capacity of the equipment, so it is required to fully consider the number of users and capacity of the DC branch output in the design to meet the needs of future communication equipment access. Before the branch switch for charging the battery pack, an undervoltage protection relay should be installed. When the battery pack discharges to the undervoltage alarm value, an alarm will be issued. When the discharge reaches the undervoltage cut-off value, the battery pack will be automatically disconnected to protect it from damage caused by overdischarging. Nowadays, air switches are commonly used for DC branch output switches, and attention should be paid to configuring and using DC air switches because they have strong arc extinguishing capabilities, and ordinary AC air switches should not be used.
Battery pack.
The battery pack is an indispensable component of the communication DC power supply. Once the battery pack fails, it will cause all communication equipment that uses the battery pack as a backup power supply to stop working in the event of a power outage in the mains, resulting in communication interruption. The battery packs currently in use are valve regulated sealed lead-acid batteries (VRLA), which completely replace the ordinary open lead-acid batteries used in the past. They adopt a sealed structure, have basically no acid gas leakage, can be installed in the same room as the equipment, and do not require electrolyte maintenance; Various combination installation methods such as vertical, horizontal, single-layer, multi-layer, etc. can be used for flexible installation; Apply float charging working system to make the voltage of the power supply system more stable; The lifespan and capacity are greatly affected by temperature. The capacity of the battery pack determines the operating time of communication equipment after a power outage. Generally, the capacity of the battery pack can be selected based on the load size and discharge time. The calculation method is: load capacity (A) x discharge time (h) ÷ discharge time hourly rate discharge capacity coefficient.
Monitoring module.
The monitoring module serves as an intelligent control center for communication DC power supplies, mainly with monitoring functions, including monitoring AC input voltage and current, parallel output voltage values of rectifier modules, output current of each rectifier module, load current, battery pack charging and discharging current and voltage, etc; Control functions, including the on/off of the power system, the on/off of each rectifier module, the setting of DC output voltage and output current limit values, the setting of battery float charging, balanced charging voltage and charging current limit values, the compensation of battery temperature coefficient, and the setting of battery undervoltage protection, etc; Alarm function: When certain parameters reach or exceed the set alarm value during the operation of the power supply, the monitoring mode will issue an audible and visual alarm and display the fault location and cause. In addition, the monitoring module should also be able to communicate with the higher-level monitoring center through RS232/RS485 interfaces to achieve centralized monitoring.
