Application and development of integrated power supply in the communication industry

As competition in the communications industry becomes increasingly fierce, communications operators are paying more attention to the rapid development of their services and the quality of the entire network. As the heart of the entire network, the network energy system is an important part of the entire network. Operators need a reliable and stable communications power system with good cost-effectiveness, adaptability to different usage scenarios, so as to effectively solve the bottleneck constraints of large-scale communications construction and development, implement the national energy conservation and emission reduction policy, and achieve high network availability. Under such circumstances, it is a general trend to establish a complete "network and energy integration" communications power room.

Requirements for power systems in 3G network construction

The core requirements of 3G network construction are:

● Rapid network construction and modular design;

● Stable and reliable;

● Green and energy-saving, in line with the national energy conservation and consumption reduction policy;

● All-round coverage.

ZTE's first "distributed base station solution" can effectively meet the above four core requirements. Compared with traditional base stations, "distributed base stations" have obvious changes in physical structure, power supply mode, engineering maintenance, protection, etc., and the corresponding power support system must also adapt to such changes.

● More power saving in power supply: The topology of the wireless side of the distributed base station has changed from a 1:1 relationship between baseband and radio frequency to 1:N. Correspondingly, the number of power supply nodes has also changed from a few to many, from a set of power supply systems for the transmission base station to multiple sets of power supply systems.

● The physical structure of the wireless base station has changed from traditional cabinet-type equipment to a variety of forms such as modular, embedded, and wall-mounted, and the power supply scheme has also become diversified.

● Centralized power supply has changed to distributed power supply: The line connection of wireless equipment has changed from multiple groups of antenna feeder groups connecting BTS and antennas to a simple transmission line and power line plus antenna feeder group. The power supply scheme has also changed from the traditional centralized power supply method to distributed power supply.

● Changes in the engineering maintenance interface: Distributed power supply expands the power engineering maintenance interface into three sections, namely the BBU power supply section, the remote power supply section between BBU and RRU, and the RRU power supply section. ●

Increased difficulty in lightning protection: Distributed base stations have DC remote power supply and DC RRU side near-end power supply, which increases the pressure on DC lightning protection and remote AC lightning protection.

● Increased difficulty in anti-theft: The increase in power line remote power supply and outdoor equipment will increase the difficulty of anti-theft.

Integrated power supply solution

In order to meet the power supply needs of various application scenarios arising from the rapid development of 3G mobile networks, integrated communication power supplies have developed rapidly and formed multiple series of products.

Front terminal type valve-regulated lead-acid battery

In traditional wireless base stations, in order to ensure uninterrupted power supply, 1-2 groups of batteries are configured for communication power supply. In order to ensure the normal operation and daily maintenance of the battery, the area occupied by the battery group is about 1/3 of the base station room. In order to achieve the goal of saving land, materials and reducing costs, China Mobile launched the "Green Action Plan", and the use of 12V front terminal type batteries has become an important task in its action matrix. China Mobile proposed relevant standards and requirements at the end of 2009.

The connection of 12V front terminal type battery is located at the front end of the battery, and the lead-out pole is placed at the top of the same end. The positive and negative poles of the battery are adjacent, which is convenient for connection and loading and unloading. The battery length-to-width ratio reaches 3.4~5, and the surface area is large, so it has excellent heat dissipation performance. The battery structure is compact and can be installed in various forms such as cabinet, stand, horizontal, and ground placement. Compared with a single 2V battery, the number of 12V front terminal type batteries is reduced by 5/6. If it is built into the switch power supply cabinet, it can greatly save the area of ​​the machine room.

Indoor integrated base station power supply

The traditional typical mobile base station is basically built indoors. The configured base station power supply is placed side by side with the cabinet-type main equipment such as BTS, cabinet-type BBU, and transmission. The height of the cabinet is consistent with the main equipment, which is basically 1.6m high. The upper part of the power cabinet is the DC distribution and outgoing part, the lower part is the AC incoming line and lightning protection distribution part, and the middle part is the rectifier module and monitoring module. There is basically no space inside the cabinet to install batteries and other equipment.

With the development of 3G networks, indoor integrated base station power supplies are developing rapidly. The cabinet structure of the indoor integrated base station power supply has obvious changes. It is divided into two compartments, the upper part is the power supply compartment, and the remaining 2/3 is the battery compartment. The AC and lightning protection distribution parts originally placed in the lower part of the cabinet, the rectifier module and the monitoring module in the middle are all concentrated in the power supply compartment. Figure 1 shows ZTE's indoor integrated base station power supply ZXDU68S301, with a maximum system capacity of 48V/300A; it has 4 layers of battery compartments, and can store up to 4 groups of 12V front terminal batteries with a capacity of 150Ah, reaching a capacity of 600Ah; it has the widest AC input voltage range in the industry (80-300V); the power supply compartment is isolated from the battery compartment, and has battery low voltage protection function and secondary power-off function; it has battery temperature compensation function, and the battery group allows compensation range of 1~6mV/Cell/℃, and temperature compensation range of 0～35℃.