Solving UPS power supply problems in the financial industry-EEWORLD

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introduction

With China's reform and opening up, foreign banks have continued to pour into China in recent years, which has had a certain impact on the financial industry market, triggering a new round of infrastructure construction and IT hardware investment needs. Therefore, it has brought certain market opportunities to IT hardware equipment manufacturers, especially UPS manufacturers. Although the global financial crisis has not yet bottomed out, the performance of China's financial industry in the global financial market can be described as "the scenery is unique here". With the gradual implementation of the national economic stimulus plan, the scale of bank credit has expanded rapidly, which is undoubtedly beneficial to the overall performance of China's banking industry. With the development of the financial industry, Eaton, a leading global diversified power management company, has proposed a UPS power supply consolidation solution for the banking industry and successfully applied it to a foreign bank.

1 Basic requirements for UPS system

1.1 Wide input voltage range

The input voltage range of UPS represents the ability of UPS to adapt to the power grid. At the same time, the wide voltage range also reduces the user's investment cost and saves energy and protects the environment. The power supply system of this project requires a backup delay time of 15 minutes and 8 hours, so a large number of batteries need to be invested in the system. The wide input voltage range of UPS can effectively reduce the number of battery charge and discharge times, achieving energy-saving and environmental protection effects.

1.2 High overall efficiency

The power consumption of IT computer rooms is very large, and the annual electricity cost is very huge, so efficiency is particularly important when selecting power equipment. Therefore, efficiency is a very important parameter when selecting UPS for the power supply system of IT computer rooms in the banking industry.

1.3 Intelligent fan management function

The heat dissipation of UPS is basically completed by fans. If the fan fails or the speed is not enough, the operation of UPS will have problems. However, most manufacturers' UPS do not have a pre-alarm function for the fan. This project proposes an online speed detection function for the fan, which can effectively extend the service life of the fan.

1.4 Small size and light weight

The IT power system room is on the 11th floor, which requires the UPS to be small in size and light in weight so as to meet the load-bearing requirements of the room. At the same time, the space in the power room is very limited. When selecting equipment, it is best to select small and light equipment on the basis of ensuring the quality of the equipment, so as to save space in the room.

2 Basic requirements for energy conservation and environmental protection

2.1 Comply with ROSH environmental protection requirements

The UPS is required to have green environmental protection functions, and it itself should also meet the requirements of green environmental protection. Therefore, when choosing a UPS, you should check whether the manufacturer has passed the RoHs standard.

2.2 High input power factor, low input harmonic current

Green UPS must have high input power factor and low harmonic current. High input power factor can improve the utilization rate of UPS to the mains, reduce reactive power loss, and achieve energy saving. Low harmonic current can reduce the pollution of UPS to the power grid and achieve environmental protection. At the same time, improving input power factor and reducing input current harmonic distortion can also reduce the capacity of cables, fuses, circuit breakers, etc. at the input end of UPS, reduce the capacity of generator matching, and reduce the user's investment cost, etc.

The best way to solve the problem of UPS input power factor and harmonic current is to use a high-power full IGBT rectifier inverter UPS. This type of UPS can increase the input power factor to ≥0.99 and reduce the harmonic current to less than 3% without the need for an external filter.

3 Requirements for batteries

The main reason why UPS is called an uninterruptible power supply is the presence of batteries. Therefore, whether the batteries can operate stably directly affects the stable operation of the UPS. Customers require that the batteries should be from well-known foreign brands and that the batteries should be monitored online, specifically to detect the battery's single cell voltage, current and internal resistance.

Judging from the requirements of this project, the greenness and reliability of UPS are the most important indicators that users are most concerned about.

4 EatonUPS power supply solution

In response to the needs of this project, Eaton provided a dual-bus power supply solution with the highest reliability currently recognized in the industry after a comprehensive analysis. The UPS equipment uses Eaton's flagship products Eaton 9390-120kVA and Eaton 9155-10kVA UPS products. The Eaton 9390-120kVA UPS system product is the latest generation of medium- and large-capacity UPS uninterruptible power supply with three inputs and three outputs launched by Eaton. The power ranges from 40-160KVA, and its design purpose is to meet the needs of today's computer network systems for centralized power supply, and is very suitable for various system applications.

The following is a detailed description of how the Eaton 9390-120KVA system solves customer needs.

4.1 Green Energy Saving

1) Extremely wide input voltage range: Eaton 9390-120kVA UPS system uses full IGBT rectifier inverter technology, which can achieve an input voltage range of plus or minus 20% under full load, thereby minimizing the number of battery discharges.

2) Extremely high overall efficiency: When the Eaton 9390-120kVA UPS system is fully loaded, the overall efficiency is as high as 94%. For this project, the UPS is working under half load, and the efficiency is still as high as 93%, which greatly reduces the user's operating costs.

3) Extremely high input power factor: Eaton 9390-120kVA UPS system uses IGBT rectification technology for input. The input current of UPS completely tracks the input voltage, and the input power factor can be as high as 0.99. Eaton 9390-120KVA UPS system uses active harmonic control. The superiority of Eaton's high-frequency switching technology means that UPS itself will not generate harmonics, so there is no need for control, and the harmonic content can be easily controlled to less than 5%.

4.2 Reliability

1) Fan management: The fans of Eaton 9390-120KVA UPS system adopt a drawer-type structure, which is easy to replace. It adopts N+1 redundant fans, and any fan failure will not affect the cooling effect of the whole machine.

2) DSP digital control: Eaton 9390-120kVA UPS system uses a 32-bit DSP digital control chip. All internal UPS systems are digitally controlled, and there is no potentiometer inside the entire machine. This not only improves the speed of event processing, but also greatly improves the reliability of the entire machine operation, avoiding the defects of analog control parameters drifting over time.

3) Control power supply: For the core power supply of the UPS itself, the Eaton 9390-120kVA UPS system uses two redundant logic power supplies as its core control power supply. If any power supply fails, it will not affect the normal operation of the entire machine.

4) Output transformer: For Eaton 9390-120kVA UPS system, the standard configuration does not include an output isolation transformer, because the UPS using IGBT rectification technology can directly invert and output 380V without a transformer.

4.3 Battery Online Detection System

For this project, Eaton provided original batteries from GNB in the United States. In order to meet the requirements of online testing of battery cells, Eaton configured the world's most advanced online battery management system, CellWatch. The Cellwatch system is the flagship product of NDSL in the United States. With its superior performance, it has been widely used in the UPS and switching power supply industries, saving battery operating costs for users around the world.

The CellWatch battery monitoring system can monitor the working status of each battery cell, battery voltage, current, temperature and battery internal resistance in real time. At the same time, by monitoring the 4 alarm dry contact signals in the CU unit, the alarm information can be easily uploaded to the TMS system through the RS485 bus. The communication method can be based on the MODBUS-TCP/IP protocol to transmit, or based on RS485 to transmit alarm information.

CellWatch system schematic

5 System solution schematic diagram

This project uses a dual power supply system. Each bus consists of two 9390-120kVA UPS to form a 1+1 parallel system. At the same time, a 9155-10KVA UPS is also configured to provide uninterrupted power supply protection for users' small servers.

Advantages of this system: The two buses are completely independent systems. When any of the buses fails, the other bus automatically bears the entire load. At the same time, the parallel UPS system is equipped with a manual maintenance bypass switch, which ensures that the UPS can be maintained online while providing uninterrupted power to users. The transformer is also equipped with a maintenance bypass switch, which allows users to inspect and repair the various terminals of the isolation transformer in real time. In addition, the system took into account the space of the user's computer room at the beginning of its design. Therefore, all UPS and isolation transformers are placed against the wall, and are truly front-maintenance products. For details, please refer to the computer room floor plan.

Dual bus power supply system block diagram

It can be clearly seen from the above figure that each bus is equipped with a generator as its backup power supply. At the same time, the AC power inputs of the two buses are different, which maximizes the guarantee that the UPS can always be in normal working condition.

Parallel system detailed diagram

The above figure is a detailed diagram of the 1+1 parallel system for each bus. The UPS and isolation transformer are equipped with corresponding maintenance switches. At the same time, each UPS system is equipped with a corresponding battery pack to provide users with uninterrupted reliable and pure power.

6 Conclusion

Under the government's macro-control, my country's financial industry has not experienced the turbulence seen in developed countries' financial institutions, which has provided a good external environment for the development of China's UPS market. At the same time, under the adverse impact of the financial crisis, a large number of foreign banks have continued to pour into the Chinese mainland market, which will inevitably lead to the UPS financial market maintaining a relatively high rate of stable growth. As a world-renowned UPS solution provider, Eaton will continue to devote itself to the construction of China's financial market and provide the most reliable power supply solutions for the stable operation of China's financial market.

Reference address：Solving UPS power supply problems in the financial industry

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