Lan UPS selection and configuration White Paper

UPS (uninterruptible power supply) is an important component in the information technology field. It is a high-tech power supply device integrating power technology, control technology, signal detection and communication technology, it is widely used in many application fields, such as computer and network systems, telecommunications/mobile communication, and various automatic production pipelines. Rapid development of computer technology, lan and Its Application However, the power supply system and power supply configuration of LAN have not been paid enough attention. According to the investigation by relevant departments, the most common problems in Lan are various faults caused by power outages and power supply exceptions. According to tests by professional organizations, a computer experiences more than 120 power problems each month on average. To ensure the safe operation of the LAN, UPS must be installed in important applications to prevent data loss and errors caused by sudden power outages. Therefore, how to reasonably and correctly configure and select an uninterruptible power supply device (UPS) has become one of the key factors for the normal operation of the LAN.

In the LAN, the main purpose of UPS configuration is to provide stable, reliable, and high-quality power supply for various electrical equipment in the LAN. It is mainly reflected in the following three aspects:

(1) provide backup power for all types of electrical equipment to prevent damage to the LAN caused by sudden power outages and affect normal operation;

(2) The power supply quality can be improved by eliminating such phenomena as surge, harmonic interference, frequency drift, intermittent waveforms, high voltage or low voltage, etc, protect electronic components of various devices in the LAN from destructive damage;

(3) UPS can also suppress clutter generated by other electrical equipment in the power grid, such as high-frequency signals, to avoid faults such as data transmission failure caused by clutter and improve network reliability.

1. functions and features of UPS
1.1 functions of UPS

UPS has the following functions:

(L) when the mains supply is interrupted, the battery can use its own battery to convert the DC power to v ac power supply to the computer and network system through the inverter circuit, ensure the normal operation of the computer and network system.

(2) The voltage can be stabilized when the grid voltage fluctuates.

(3) It can suppress Power Harmonic Interference, instantaneous voltage drop, high-voltage surge, voltage waveform distortion, electromagnetic interference, and other power pollution of the power grid, provides stable voltage and pure waveform power supply for computers and other equipment to ensure normal operation and data of computer and network systems are not disturbed.

1.2 characteristics of UPS

For a set of high-quality UPS power supply systems, it should have the following features:

(L) High Reliability

The system shall have the power supply capability to provide 365 × 24 continuous high quality UPS inverter power supply. This means that during the operation of the UPS power supply system, no instant power supply interruption or power failure is allowed, it is not allowed to directly load the power supply to the user through the AC bypass of common mains supplies. To this end, the UPS power supply system must meet the following requirements:

As the failure rate of a single UPS instance is low, the average working time (MTBF) of large UPS products is 0.2 million ~ 0.4 million hours.

The "N + 1" type UPS redundant parallel system with high fault tolerance function is used to further improve the reliability of the UPS Power Supply System (the typical MTBF Value of the "1 + l" type redundant parallel system can reach 1.4 million ~ 2 million hours ).

There should be no single point of failure (spof) risks in the entire UPS power supply system.

Allows you to maintain and maintain the power without stopping the power supply.

In case of a short-circuit fault on the user's device, the impact of the fault should be minimized.

(2) high anti-interference Performance

The UPS power supply system enables Internet devices to achieve high "availability" and create excellent operating environments for them.

A large number of operation practices show that power interference is one of the important reasons for the decline in the "availability" of internet devices. It should be noted that power supply interference not only comes from common mains grids, but also from imperfect UPS and users' Internet devices. This is because the servers, disk arrays, and switches configured in IDCs and MDC data centers all have built-in switch power supplies. This type of rectifying and filtering nonlinear load will reflect the UPS Power Supply System 3 ~ 23 times of low harmonic interference may lead to adverse consequences of reducing the voice quality. Practice has proved that power supply interference is too high and too frequent, which may lead to hidden faults such as reduced Internet transmission rate and increased packet loss rate of network servers, as a result, internet devices are forced to enter the "drop-down usage" status, which can lead to network paralysis in severe cases.

It can be seen that the rapid development of high-speed information network technology puts forward more stringent requirements on the power quality provided by the UPS power supply system.2. UPS Classification

UPS is divided into three types: backup, online and online interactive.

(1) backup UPS

When the mains supply is normal, the mains supply the load device, and Floating battery charging. When the mains voltage fluctuation exceeds the specified value, the inverter circuit is started to convert the DC power of the battery to a stable AC power output to power the load. Because the mains supply directly supplies power to the load, the Standby UPS cannot eliminate electrical pollution such as surge, Spike, and frequency drift on the mains network, and the capacity is relatively small. However, the technology is simple, cost-effective, and the price is relatively low. It is used in many scenarios where the voltage stability is not high.

(2) Online UPS

Online UPS keeps the inverter in the working state. When the mains supply is normal, it first converts the mains AC to the direct current through the circuit, and then converts the direct current to the sine wave AC to power the load, in the case of power supply, it can also regulate the output voltage and prevent electromagnetic interference. It also uses a charging circuit to charge the battery floating. When a power failure occurs, the direct current of the battery is used, so the inverter does not have a switching time, so it is suitable for scenarios with high requirements on the power supply.

(3) Online Interactive UPS

This is an intelligent UPS. In addition to the online UPS function, it can also automatically detect the mains voltage and provide high-precision sine wave AC output. Online Interactive UPS also provides the ability to communicate with computers, some can connect to the Internet, and some can manage UPS through the network, in addition, the working status and output status of the UPS can be automatically adjusted according to the working conditions of the computer and network system. In case of a fault in the UPS, the computer system can be notified to start redundant backup power supply, so it is called smart UPS. It is generally used in scenarios with high power requirements for servers, routers, switches of large backbone networks, and some workstations in network systems. It will greatly improve the reliability of computer systems.

3 UPS technology development and application
3.1 smart UPS

With the continuous development of electronic technology, many new technologies and new components are constantly applied to UPS products. Therefore, the development of UPS products has gone out of the old path of blindly pursuing high electrical performance, began to pursue the product's high reliability and high stability.

Currently, Online Interactive UPS can communicate with computers through RS232, RS485, or Ethernet network interfaces. with corresponding software, it can perform local/remote monitoring on the UPS, the availability of UPS is greatly improved. Driven by the rapid development of computer networks and communications, UPS has developed into an intelligent UPS system based on a large number of introduction of microprocessor monitoring technology. The so-called "smart UPS" refers to the addition of communication interfaces on the UPS host, it is connected to the corresponding communication interfaces on computer servers, routers, gateways, and other devices through a dedicated communication cable or a modem to establish a bidirectional communication control and management function, it also installs power supply monitoring software suitable for various operating platforms, manages UPS operation and operations, and improves UPS efficiency. Intelligent UPS can monitor UPS input and output voltage, input and output frequency, output current, battery voltage, UPS host temperature, and other operating parameters in real time, after the specified time of UPS failure or battery power supply, the data in the computer is automatically archived, the system is exited, and the system is shut down. The system administrator can be notified by calling or email. For networked smart UPS, you must also configure the corresponding Nic to include UPS management in the network management system.

3.2 smart management of UPS

In order to achieve the purpose of UPS to protect the entire LAN system, UPS's intelligent management function is particularly important. Therefore, the intelligent UPS with internal microprocessor configuration is a new trend in the development of UPS. Through the combination of hardware and software in the UPS, and using interfaces or dedicated network adapters, the system administrator can remotely and intelligently control the running status of the UPS, greatly improve the UPS function. For example, it can be used to monitor UPS output voltage frequency, mains voltage frequency, battery status, and fault records. It can also detect battery, automatically charge and discharge, and remotely switch hosts through software.

3.3 UPS Monitoring Technology

To achieve UPS management, an effective power management system must be established, that is, the physical information transmission interface, logical communication protocol, and UPS information database management must be established. A complete power management system is usually composed of power management software and smart accessories. That is to say, intelligent UPS Monitoring is composed of hardware and software monitoring.

Generally, UPS Monitoring Technology can be divided into the following types:

(1) Monitoring Technology Based on Serial Communication

Serial Communication is a traditional communication method for UPS software and accessories. It is mostly used in small and medium power UPS solutions. Its advantages are safe, reliable, and easy to install, however, the limitation of this communication mode is that the communication distance is short, which is mainly used for UPS Monitoring in the LAN and the security protection of connected computers.

(2) Web-based Monitoring Technology

The Web-based software/attachment monitoring technology was born with the development of the Internet, and the attachment is mainly Web/SNMP Management Card. In a data center or a large computer network, UPS usually protects multiple computers. Communicate with the computer and the UPS through TCP/IP, and the system administrator monitors the UPS distributed within the WAN through a Web browser, and regularly generates UPS status reports.

(3) SNMP-based Monitoring Technology

The SNMP-based software/accessory monitoring technology is closely related to the development of network management products. It is mainly used in enterprise-level networks with a large number of upss and a wide distribution. Configure an Eni for the UPS instance or directly integrate the SNMP adapter into the UPS instance to control and diagnose the UPS instance as an independent node in the network.

(4) Monitoring Technology Based on Modem/telephone/paging network

Dial-up Internet access: use an Internet browser to remotely monitor the UPS, display the working status of the UPS in various ways, regularly enable, shut down, and perform self-check, and trigger alarms in various ways in case of faults. After recovery, cancel the shutdown operation and send the corresponding information.

3.4 Development Trend of UPS Monitoring Technology

The close integration of the UPS system and Internet technology makes it more meaningful to increase the ease of use of the entire information system than ever before. Although traditional technologies such as telephone dialing, SNMP, and Telnet have achieved remote and centralized monitoring of UPS, these technologies usually require specific device configuration and operation skills. With the popularity of the Internet, browser monitoring of UPS will become the mainstream of UPS Monitoring Technology.

In the future, the network will become more extensive and global, which will inevitably complicate the network. Multiple forms of network systems will be connected together. As part of the network system, UPS is required to be able to monitor on various network platforms. With the rapid development of Internet, Intranet and e-commerce, users have higher and higher requirements on network availability, this extends the protection of critical network devices to the protection of the entire network path. Therefore, in addition to providing comprehensive monitoring and protection functions, the monitoring software must also support mainstream operating systems, cross-platform operations, and have plug-and-play functions; Support mainstream databases and application software; integration with mainstream server management tools and mainstream network management systems.4. Lan UPS Selection

4.1 UPS selection principles

A typical LAN usually has servers, network switches, routers, network management workstations, data storage, PCs, and printers And various other terminal devices. Because the number of nodes in the LAN is large and each node may be scattered in different locations, multiple UPS instances located in different locations need to be maintained. Therefore, the UPS used in the LAN has its own characteristics. You must pay attention to the selection and configuration.

Generally, 10 ~ 20kVA medium-capacity UPS centralized power supply mode, and dual-machine hot backup or parallel power supply, to ensure safe and reliable power supply. For a large number of PCs, routers, printers and other devices that cannot be centrally set in the LAN, distributed UPS should be used in the field to provide power assurance, the on-line UPS device that is not contaminated with the power grid should be preferred. This is because both the Backup Type and Interactive UPS are low-end products, and their reliability and failure rate are inferior to those of online UPS. In addition, in the case of poor power grid environments, basically, the power grid interference cannot be prevented from being transmitted to network devices, which may easily affect the normal operation of the LAN.

4.2 precautions for choosing UPS

The layout of load equipment in the LAN should be reasonably set, and the centralized power supply mode of a single large-capacity UPS should be adopted as much as possible. In this way, not only the investment cost per unit power of UPS can be reduced, but also the failure rate of UPS can be reduced and the utilization rate of battery can be improved.

You must select the UPS models that allow larger fluctuations in the mains supply range, and consider the specific requirements of different distribution power systems in the LAN to adapt to their load-carrying capabilities.

Select a UPS model with strong overload capacity and short-circuit capability to reduce the chance of UPS switching operation and reduce the failure rate of UPS.

In the LAN, appropriate anti-transient surge suppression devices should be configured to better protect network equipment, and UPS models with low output zero line to ground potential should be selected to obtain the highest possible data transmission rate, it also reduces the error rate of data transmission.

According to the centralized monitoring requirements of different levels in the LAN, it is necessary to configure an intelligent UPS model with different network control functions to meet the needs of network functions and avoid investment waste.

5. UPS Maintenance
Now UPS has been widely used. UPS is a simple but vulnerable device. Scientific Use and Maintenance of UPS can improve the availability of UPS and prolong the service life of UPS, pay attention to the following points during normal use:

(1) do not use it to connect inductive loads, because the starting current of inductive loads during startup is usually 3 ~ of the rated current during normal operation ~ 5 times, it is easy to cause the UPS instantaneous overload, affecting the UPS life.

(2) do not run at full load. The use of UPS at full load for a long time will directly affect the life of the UPS. Generally, the use of UPS is based on 120% ~ 150% select UPS, such as 1kW load generally choose 5kW UPS.

(3) The battery is well maintained. Most of the batteries used by UPS are maintenance-free sealing lead-acid batteries. Although it is maintenance-free, improper maintenance can also shorten the life of the battery. For UPS, especially the standby UPS, if the local power is not stopped for a long time, the power supply should be interrupted on a regular basis (generally three months) so that the battery can discharge the load to maintain the battery power storage performance, of course, this process requires dedicated personnel.

(4) Pay attention to lightning strikes. Ensure the effective shielding and good grounding of the UPS to protect the safety of the internal circuits and batteries of the UPS.

(5) Pay attention to the safety of electricity usage. Do Not disassemble and maintain UPS products at will to avoid security incidents. Because the output of UPS is generally 220 v ac, there is a risk of electric shock, so it is generally necessary to ask professional service personnel to repair.

6 conclusion
Correct and safe use and maintenance of UPS will ensure the security of devices powered by UPS on computers, networks, and other applications, and improve the reliability and stability of load equipment and data, it gives users a safe environment to use, in order to create good social and economic benefits. Article entry: aaadxmmm responsible editor: aaadxmmm