Battery is the most important part of communication power supply technology maintenance work (1)

pushu009azx

Battery is the most important part of communication power supply technology maintenance work (1) [Copy link]

Battery is the top priority in the maintenance of communication power supply technology
Source: Power Communication Network/Li Kemin

The normal operation of the power supply system is the basis and guarantee for smooth communication. The goals of operation and technical maintenance are: to ensure safe, reliable, stable operation and high-quality power supply of the power supply system; automatic start and withdrawal, accurate and effective closed-loop control, and real-time and correct reception of instructions and feedback of information; to ensure the service life of equipment and reduce the overall operating cost.

　　In the DC uninterruptible power supply system, the rectifier is the heart, the backup generator is the key to improving the availability of AC power supply, and the battery is the basis of uninterruptible power supply. The basic requirements for battery operation and maintenance are: to keep the battery in a fully charged state without overcharging.

When charging, when supplying power to the host alone, more than 80% of the rated capacity should be discharged.

　　The batteries we are talking about here include basic power supply (24V, 48V) batteries, batteries, generator set starting batteries, etc.

　　Valve-regulated sealed batteries have been widely used because of their outstanding features, but there are still some issues worth noting in manufacturing and operation. It should be kept in mind that they are by no means maintenance-free batteries. For this reason, on February 22, 1994, the former Ministry of Posts and Telecommunications and the General Administration of Telecommunications (1994) No. 108 document was issued to all provinces, pointing out that the cathode absorption sealed lead-acid batteries currently equipped with safety valves are not maintenance-free batteries (called valve-regulated sealed batteries). Do not be misled by maintenance-free.

1 Why is the battery the top priority in the maintenance of communication power supply technology?

　　From the analysis of many aspects such as the working status, imperfections, and power supply failure statistics of batteries, the technical maintenance of batteries should be the top priority.

　(1) If a host device fails, channel conversion, wave channel conversion, system conversion, etc. can be performed to ensure smooth communication. Unless the CPU fails, it will generally not cause the entire system to be paralyzed. The communication host device requires an uninterrupted DC power supply. If the battery alone supplies power to the host, once a failure occurs, the battery reaches the discharge termination voltage in advance and the power supply is interrupted, which will cause all devices powered by the battery pack to stop working, resulting in large-scale communication paralysis; if the AC is interrupted, the UPS battery will fail, which will cause all billing systems and computer systems powered by the device to stop working. When the generator set is started, the battery fails and the unit cannot be started. In short, the characteristics of the communication system determine that battery maintenance is the top priority in technical maintenance work.

　(2) Although valve-regulated sealed batteries have outstanding features, such as no acid mist escape under normal circumstances, can be placed in the same room as the main engine, and are suitable for distributed power supply and vehicle-mounted power supply, there are still some unsatisfactory aspects in terms of production, manufacturing, operation and maintenance. There are two types of valve-regulated sealed batteries: one is a valve-regulated sealed battery (AGM) using an ultra-fine glass fiber diaphragm; the other is a valve-regulated sealed battery using a colloidal electrolyte. They both use the cathode absorption principle to seal the battery. Therefore, there must be about 10% of the diaphragm gap in the diaphragm of the AGM battery. For colloidal sealed batteries, after the injected silica sol becomes gel, the skeleton needs to shrink further. The viscosity of the silica sol should be controlled at about 10, so that cracks appear in the gel and penetrate between the positive and negative plates. The gaps or cracks provide a channel for the oxygen released from the positive plate to reach the negative electrode. In the production of AGM batteries, if too much electrolyte is poured, it will be detrimental to the recombination of oxygen at the cathode, and if too little electrolyte is poured, the internal resistance of the battery will increase. In the production of colloidal batteries, if the viscosity of the silica sol is too high, that is, too much silicon solution is added, it will cause the gel to have too large cracks, increase the internal resistance of the battery, and vice versa, it will be detrimental to the recombination of oxygen at the cathode. Therefore, valve-regulated sealed batteries have very strict requirements on production processes. During the use of valve-regulated sealed batteries, due to gravity and the inability to add distilled water, the electrolyte uniformity is poor, and water loss is an important factor in premature failure. Therefore, it has strict requirements on working environment, temperature, floating charge voltage, and charging voltage.

　(3) According to statistics, more than 50% of power supply system failures are caused by battery failure or improper battery maintenance. The following are some communication power supply failures we have learned about in the past decade.

　　In 1992, in the ×× Bureau, the low-voltage alarm point of the battery was adjusted too low, and when the alarm occurred, it quickly reached the termination voltage, causing communication interruption;

　　In 1993, in the ×× Bureau, the battery exploded at the moment the engine was started because the starting battery was overcharged, the cover was screwed too tight and the vent hole was blocked;

　　In 1994, the ×× Bureau, because the acid-proof flameproof cap of the acid-proof flameproof lead-acid battery had not been cleaned for a long time, the charging voltage was too high, and the battery exploded at the moment of discharge;　

　　In 1995, in ×× Bureau, due to the battery’s long-term low floating charge voltage and insufficient charging, the battery quickly dropped to the termination voltage during discharge, interrupting communications;　　　　

In 1996, in the ×× Bureau, one group was acid-proof and flameproof lead-acid batteries, and the other group was valve-regulated sealed batteries. The two groups of batteries were operated in parallel, causing one group of batteries to be overcharged and the other group to be undercharged;　　

　　In 1997, the 3000Ah valve-regulated sealed battery of the ×× Bureau was designed to discharge for 3 hours, but due to leakage and drying, it could only discharge for more than ten minutes;　　

　　In 1998, several microwave circuits had low float charge voltage and incompletely charged batteries, so the discharge time reached the termination voltage very quickly, interrupting communications;　　

　　In 1999, the communication of ×× Exchange Bureau was interrupted due to long-term high floating charge voltage, electrolyte drying, city power outage and battery failure (during the Directors' Meeting);　　

　　In 2000, in ×× Bureau, because the battery connection strip was not tightened, the contact resistance was large, and the pole sealing agent melted at the moment of discharge;　　

　　In May 2001, communications at ×× Bureau were interrupted due to long-term high floating charge voltage of the battery, drying up of the electrolyte, and battery failure during discharge. In July of the same year, communications at ×× Bureau were interrupted due to overcharging, which caused the battery to explode at the moment of discharge.　

　　Looking back at some of the more serious and typical battery failures that have occurred since 1992, we can draw an important warning that battery maintenance must be given an important position in the maintenance of communication power technology.