Power Supply
Normal power supply is the prerequisite for proper running of the USG. This section describes the requirements for power supply.
Basic AC Power Supply
- Communications devices must be equipped with AC power supply with the rated voltage ranging from +5% to -10%.
- Communications power supply devices and key constructions must be equipped with AC power supply with the rated voltage ranging from +10% to -15%.
- The frequency of the AC power current ranges from +4% to -4%, and the sinusoidal distortion rate of voltage waveform must be 5% or less.
- The AC neutral for communications purposes must be a conductive wire that has the same cross section as the phase cable.
- The selection of the DC power feeder depends on the long-term load. If the cross-sectional area is greater than 95 mm2, use the rigid busbar. If the short-term load differs greatly from long-term load, lay out the cables by stages.
- The DC and AC conducting wires must be fire resistant and the wiring must comply with the Class A Fire Resistance Design Norm for High-Rise Civil Buildings (GB50045-95). The low-voltage power distribution facilities must comply with the Low-Voltage Power Distribution Facilities and Wiring Design Norm (GB50054-95)
- Use voltage regulating or stabilization facilities to restrict
the voltage fluctuation within a reasonable scale if:
- The communications devices are powered by mains, and the voltage exceeds the rated voltage by +5% to -10% or the allowed voltage range.
- The communications devices are not powered directly by the mains and the voltage of the mains exceeds the rated voltage by +10% to -15% or the AC voltage range allowed by the DC power supply device.
- Use the UPS or inverter power supply system if the communication load requires non-interruptible and non-transient AC power supply.
- Equip the site with the electric generator set to ensure normal communication in case of mains failure. The capacity of the generator set is greater than or equal to 1.5 to 2 times the capacity of the UPS.
- A UPS usually has only one batter set. Connect two or more UPSs in parallel or series for redundancy. If the inverter or UPS is used, configure the inverter or UPS that provides the maximum amount of power as the active one, and configure another inverter or UPS as the standby.
Basic DC Power Supply
Ensure the reliability of the DC power supply system at the communications site. Deploy the power supply device as close as possible to the communications devices so as to shorten the power feeder and lower the circuit voltage drop between the battery port and device port to less than 3.2 V, thereby reducing installation costs and power consumption.
Use two or more independent power supply systems if the communication volume is large or if more than two switching systems are deployed at the site.
For large communications hubs, deploy an independent power supply system on each floor, each providing power for the communications equipment room on this floor. Medium-sized communications stations can be centrally powered by a power room or storage battery room, or powered in a decentralized manner. For small-sized communications stations, the power supply system can be deployed in the same equipment room as the communications devices, but you must take appropriate measures to ensure that the corrosive gases discharged by the batteries in the equipment room do not corrode the circuit boards of communications devices.
Item |
Specifications |
|---|---|
Voltage fluctuation range allowed for the -48 V input end |
-48 V to -60 V |
Surge current tolerance capability in DC power supply |
At least 1.5 times higher than load rated current capability |
Regulated voltage precision |
The regulated voltage precision is less than or equal to 1% when the AC input voltage fluctuates between 85% and 110% of the rated voltage, the load current varies between 5% and 100% of the rated current, and the output voltage of the rectifier is any fixed value in the -46.0 V to -56.4 V range. |
On/Off overshoot magnitude |
Within the 95% to 105% range of the DC rated voltage value |
Peak-to-peak noise voltage |
Less than or equal to 200 mV |
Dynamic response |
The recovery time should be less than 200 ms, and the overshoot must be within the 95% to 105% range of the DC voltage set value. |
- Decentralized power supply is recommended. Use multiple DC power supply systems and multiple power sources.
- Use a standard-compliant DC power supply. The output voltage of the communications power supply must be in the voltage range of the device to be powered.
- Improve the reliability of the AC power supply system to properly reduce the battery capacity. When it is difficult to improve the reliability of the AC power supply system at a small communications station, properly increase the battery capacity.
- The total capacity configuration of the high-frequency switch rectifier should match the communications load power and battery charging power. Rectifier modules should use a redundancy configuration. If the number of active modules is less than or equal to 10, one standby module should be deployed. If the number of active modules is greater than 10, one standby module should be deployed for every 10 active modules.
- Storage batteries should be installed in two or multiple sets. The total capacity depends on the duration in which the storage battery sets independently supply power to the load. For most communications stations, storage battery sets should supply power for at least one hour.