A communication power supply is a power device that provides direct current or alternating current energy to communication equipment and is an important component for the normal operation of any communication system. The quality of communication not only depends on the performance and quality of various communication devices in the communication system, but is also closely related to the quality of power supply from the communication power supply system.

If the power supply quality of the communication power supply system does not meet the requirements of relevant technical indicators, it will cause an increase in telephone strings and noise, a decline in communication quality, an increase in bit error rate, and result in communication delays or errors.

Once the communication power supply system malfunctions and the power supply is interrupted, it will cause the communication to be interrupted, and even lead to the paralysis of the entire communication bureau (station), thus causing serious losses. It can be said that the communication power supply is the "heart" of the communication system and holds an extremely important position in the communication network.

The basic classification of communication power supplies

Compared with the power supply systems of industrial enterprises, the power supply systems of communication bureaus (stations) not only have similar AC power supply systems but also have unique DC power supply systems.

Most communication equipment at home and abroad, such as program-controlled switches, optical fiber transmission equipment, mobile communication equipment and microwave communication equipment, etc., are powered by direct current. Compared with alternating current power supply, it has the advantages of high reliability, stable voltage and easier realization of uninterrupted power supply. Direct current is mainly obtained by rectifying 220/380V alternating current. The rectifier takes in alternating current and outputs the required direct current. Its output terminal is connected in parallel with the battery pack, and together they provide a direct current basic power supply (generally -48V) for communication equipment. This kind of power supply is also called the primary power supply.

In addition, various communication devices also require multiple DC voltages such as 3.3V, 5V, and 12V, which are usually supplied by the DC converters inside the communication devices. The program-controlled switch is also equipped with a ringing current generator that generates ringing current signals. These power supplies installed inside the communication equipment racks are usually called rack power supplies or secondary power supplies.

Some communication equipment, such as the communication equipment of satellite communication earth stations and the receiving and transmitting equipment of radio receiving and transmitting stations, have always been powered by 220/380V AC.

1. Basic power supply

The basic power supply of communication bureaus (stations) is divided into two major categories: AC basic power supply and DC basic power supply.

Ac basic power supply

The alternating current power supply provided by the municipal power grid or backup generator sets (including mobile power stations) is called the alternating current basic power supply of the communication bureau (station).

According to the Chinese communication industry standard YD/T1051-2018 "General Technical Requirements for Power Supply Systems of Communication Bureaus (Stations)", the nominal voltage of the AC basic power supply for communication bureaus (stations) is low voltage 220/380V, that is, the phase voltage is 220V and the line voltage is 380V. High voltage 10 kv(line voltage); The nominal frequency is 50 Hz.

2. Dc basic power supply

A power supply that provides DC voltage to various communication devices, communication inverters and DC converters is called a DC base power supply.

According to YD/ T1051-2018, the voltage types of the DC basic power supply for communication bureaus (stations) are: -48V, 240V, and 336V. Among them, -48V is widely used to supply power to communication equipment, and its positive terminal is grounded. 240V and 336V have been gradually applied to power information technology (IT) equipment. The positive and negative poles of the power supply must not be grounded, which is called suspended power supply. In addition, at present, a small number of communication devices are powered by +24V(with the negative terminal of the power supply grounded) or a 24V DC power supply.