Data Center Computer Room Supply Distribution System“Lead-acid battery leakage”, The power supply interruption of the data center network system device, the electrical short circuit causes the power supply interruption of the UPS system, the equipment has failed, stopped operation, will cause a serious hazard of a fire, etc., is the most negligible By fatal hidden dangers, the following will analyze the hidden dangers of lead-acid batteries.The harm of shorting of battery pack leakage
1. Leading the Internet interruption accident
The power supply security system of the data center is the core system that guarantees the power supply of network devices, and the reserve battery pack is the network's emergency power supply energy. In the DC 240V power supply system, the battery pack is directly connected to the direct current supply circuit in the rectifier output, which is because the electric short circuit is interrupted on the backup battery pack, and the electric short circuit is interrupted on the motor power failure or the communication side is not directly leading to the communication network. Power supply interrupt. Similarly, in the AC UPS system, as long as the inverters and subsequent circuits work normally, the backup battery pack can play a role. However, if electrical short circuit occurs in the battery pack, it will inevitably cause the output voltage of the power system to fall, causing the load equipment to power out, leading to the network interruption failure, seriously affecting the smooth flow of information communication.
2, the battery pack is a DC power supply, and its circuit fault harm is larger than AC power.
In general, when the electrical short circuit is found, the power is first cut off. For AC power, due to power from the top, the electrical power supply is from the mainstream, when the electrical short circuit fault occurs, there will always be a first-level protection device to generate actions, and timely cut off the short circuit electrical circuit. When the battery pack is located at the end of the power supply system, the electric energy is provided, as long as the protection of the protective fuse or battery pack of the DC total distribution screen, no further protection will be further protected. When a short-circuit fault occurs, the short circuit electrical circuit cannot be effectively cut off. In addition, DC current is unlike a sine wave, it does not have a process of zero when there is no zero point, and the electrical short circuit is extremely easy to spread. The impedance after the short circuit depends only on the wire resistance and the internal resistance of the battery pack, and the short circuit current is approximately infinite. Therefore, the degree of harm of DC electrical short circuit in the battery pack is much larger than the AC electrical short circuit.
3, trigger a fire
After the battery pack is electrically short-circuited, if it is not possible to discover and cut off the loop in time, it will inevitably cause a fire. The more the battery pack is, the greater the harm.
Reasons for battery electrical short circuit
The common battery electrical short circuit or even the reasons for the fire generally have the following:
1. There is a problem with the quality of the battery itself, and there is a hidden danger between the pile head and the plate;
2. When the battery is transported or installed, the housing has cracks without timely discovery, and the internal acid liquid in the battery is electrically shorted by the battery frame after installation;
3, the battery and cable connection is not strong, resulting in too much contact resistance, the temperature increases after the increase in contact surface, thereby causing the contact resistance to become large, and the electrical fire or even the arc, and finally ignite the nearby flammable products;
4. The pressure resistance value of the battery pack is not enough, resulting in an insulating breakdown between the cable, resulting in a short circuit of the cable;
5, the battery configuration is unreasonable, beyond the battery discharge limit;
6. The battery connection cable is short-circuited by the battery frame iron under the trap;
7, the battery charging current is too large or the voltage is too high, resulting in a battery overhanging, and the positive and negative plate deformation is bent to the fire;
8, the external connection cable or internal connection cable of the battery pack is insulated due to excessive use time, and does not check the replacement process in time, resulting in a short circuit between the cable or the cable and the battery frame.
In theoretically, the root cause of the fault is that the battery pack or monomer is generated by a conductive body (e.g., an electrolyte, a battery holder, a wire, or the like directly forms a loop between the positive and negative poles, producing a leakage current or electrical short circuit.
Insufficient prevention measures in the leakage of the battery pack
Commonly predicted the battery leakage electric short-circuit measures and insufficient causes of electrical short circuits in the above-mentioned battery packs, the battery leakage liquid has caused a short circuit or an insulation of the battery frame, causing the positive and negative electrode through the battery frame, which has always occurred. High, most difficult to judge and discover, but the post-affected problem is very serious.
1, increase the tray at the bottom of the battery——The tray is flammable;
2, battery frame add electric board gasket——Cannot avoid the devil of the electrolyte;
3, the battery frame is electrically insulated——Not easy to implement and do not meet the safety specifications;
4, battery room installed smoke alarm system——Not timely.
Setting, troubleshooting and analysis of battery pack leakage detection
1. The battery pack leakage warning should be defined as a major alarm. When an alarm occurs, you should send maintenance personnel to the on-site investigation.
2. For a 240V DC power system, when there is an insulation monitoring alarm, if there is only the total bus voltage alarm and there is no branch leakage electric alert, after the possibility of misreading the police, it should be considered as a alarm caused by the decline in the battery pack.
3, multi-group battery pack (n = 1 ~ 4) in parallel
1 When n = 1, the battery pack leakage alarm is the only set of batteries for suspected faulty battery packs;
2 When N> 1, the proximal protection switch of the battery pack can be disconnected, and the system alarm will disappear when the system alarm disappears, which is a suspected fault battery pack.
4. Battery group leakage detection can have two forms of fixed and portable
1 240V DC system (ie, in Table 1 in Table 1), the battery pack is directly negative, and the online detection of the battery pack leakage is achieved directly by improving the system insulation monitoring.
2 Similarly, the battery pack is not grounded and there is no intermediate tap or intermediate tap that is only a neutral point without grounding, and the second and third cases in Table 1 can be set, the fixed battery pack can be set. The liquid detecting device realizes online detection of the battery pack leakage;
3 The battery pack is not grounded but there is an intermediate tap and the grounding AC UPS system (ie, in Table 1), the battery pack can be used to check the battery pack.
5. Install the fixed battery pack leak test device or begin to test the battery pack before testing and confirming that the battery pack is a pair suspension operation.
That is to meet the following:
1 The positive and negative electrode of the battery pack is not grounded;
2 The charge and discharge circuit of the battery pack is insulated or isolated;
3 There is a battery pack of intermediate taps, wherein the node is not grounded or paired.
4 For the UPS system battery pack with intermediate taps and neutral points, it can be separated from the battery frame to the power supply system by insulating the battery holder, or using the proximal protection switch of the battery pack to ensure it to the battery frame. Insulation. Recommend: LiFePO4 Battery Manufacturer Energy storage battery Manufacturer Integrated machine energy storage battery series Manufacturer Lead lithium battery Manufacturer Outdoor Backup Battery Manufacturer Portable outdoor power supply Manufacturer Power battery Manufacturer Powerwall LiFePO4 Battery Manufacturer Battery rack Manufacturers Telecom LiFePO4 Battery Manufacturer Wall mounted battery storage Manufacturer China Lifepo4 Battery
