Large data center construction boom.However, in the operation of large data centers, distribution cost is huge challenge for operators, at the same time, the power distribution unit often take up a lot of area, is not conducive to the data center of energy conservation and environmental protection.Therefore, how to guarantee the stability of large data center operation, realize the innovation of distribution system, significantly reduce distribution costs become a concern in the industry.It is under this trend, medium-pressure type UPS began to rise.Medium-pressure type UPS can increase near the center of the load voltage level, reduce the low voltage distribution, reduce energy consumption.Predictably, the telecom industry to telecoms, the reduction efficiency was deepened, medium voltage UPS system will have broad market prospects.
Large data centers low-voltage distribution system needs to be innovation
Early communication system in our country have political and security responsibilities, communication network interruption will shall be investigated for related party political responsibility, so the redundant configuration is higher in communication system in our country, from the early UPS and battery backup time inconsistency of switch power supply.So, in the construction of data center power supply system, in order to guarantee the system safety and reliability, fully considering the equipment configuration and redundancy.
Current big data center park or data center power supply structure is generally lead mains voltage (110 kv) or medium (35 kv and 10 kv) to the high-voltage transformer room and then assigned to the dry type transformer (into 380 v) and configuration of complete sets of low-voltage distribution system, complete sets of low-voltage distribution system in the feed tank through intensive bus or cable distribution of electrical energy to the low voltage power distribution ark of each floor, redistribution to large UPS (such as 500 kva, 500 kva), general each low voltage power distribution systems, the maximum configuration to 2000 kva, each low pressure system with two sets of large capacity most 11 type or 2 n type UPS system, UPS system from the high voltage distribution system - the structure of the low-voltage distribution system - UPS is widely used in the early middle and small data centers, but as the data center distribution to increase the capacity of single UPS system, the distribution structure has many defects.
First, severe waste of investment.Single set of low-voltage distribution system are wasted investment, floor space, waste, waste phenomenon such as intensive bus bar.Although the transformer can also be provided in each floor, but the power supply structure did not change, with the use of large UPS, each 2000 kva hang under the low voltage power distribution system of 2 sets of 600 kva (11) considering the charging current and load full redundancy.
Second, to increase power supply level, increase the safety hidden trouble.In the same power devices in the environment, less is safe for upstream and downstream distribution system switch, the power distribution level, the less the higher reliability, near the center of the load voltage grade, the higher the more energy-saving.Large data center park 35 kv switching station - 10 kv high-voltage power distribution cabinet to 10 kv power distribution cabinet - transformer - low voltage power distribution ark - intensive bus - floor distribution cabinets - UPS system, distribution structure of 8 levels, each one level means that increase a point fault hidden trouble.
Third, impact machine room can use area, increase the cost of construction.For large data centers, if each floor are configured transformer low voltage transformer room, UPS power supply system, the corresponding power supply area to set aside more than 40% of the space, for telecommunication room, generally reserved space (25% ~ 30%, and the bigger the low-voltage distribution structure redundancy, the greater the total room area.
Medium voltage integrated UPS is on the rise
Review the development trend of high and low voltage power distribution in the field of communication, communication system from early 380 v to 10 kv, uninterruptible power supply from 220 v to 240 v, 336 v high voltage dc, the greater the equipment power consumption intensity distribution system voltage level also rose, adopt high grade of equipment can be more to reduce the line loss, cable bus investment, save equipment area, reduce the frequency conversion means saving energy, again, change the traditional 380 v to 380 v, 220 v power distribution structure, increase the UPS to enter to 10 kv voltage level also have more advantages.Using such as 10 kv UPS is the premise of the traditional measurement function of low voltage distribution points system, power compensation function, low voltage generator transfer to 10 kv system.
Low-voltage distribution measurement can be used in high voltage measurement.Traditional data centers tend to be in low pressure measuring tank that is configured in the period of low voltage power distribution system, but as the scale of the data center is more and more big, the large data center has more than 10 sets of low-voltage distribution system, and utilized by divided into, office, etc., statistic work in high pressure will become a trend.USES the high voltage side of measurement at the same time can still through the medium voltage of the integrated UPS transformer data acquisition for automatic statistics report.
Compensation function can be changed to high voltage compensation in low voltage power distribution and load center nearby.For data center, the perceptual load and capacitive loads exist at the same time, the perceptual load mainly for air conditioning host, fan and other electrical equipment;Rectifier equipment, IT equipment for capacitive load;Also said the perceptual load data center and capacitive load is exist at the same time, is complementary.Statistics show that at present most of the communication board floor of low-voltage capacitor tank is set to manual input, because due to the perceptual load and capacitive load at the same time, the power factor cos Φ usually above 0.92.To compensate in the low-voltage distribution system belong to the compensation, did not play an effective role, and easy to cause resonance capacitor in harmonic environment and explosion hazard.So the future of data center should be aimed at specific room environment test its harmonic and reactive compensation load is nearby.
Large data centers with high pressure oil machine is an inevitable trend.At present large, very large data center has been promoted with high pressure oil machine, offers many advantages: cable, upstream and downstream switch configuration, simplifies the distribution structure, high pressure oil machine use high voltage cable transmission of electricity, equivalent to one over twenty-six of the low-voltage transmission current transmission current, upstream and downstream switch and cable and convenient construction, investment and savings, line loss is very small, safety is higher;For multimachine weaver, forming large capacity backup power supply, to eliminate the output capacity bottleneck of normal pressure oil machine system faces;If using high pressure air conditioning must use high pressure oil machine, centrifugal machine starting current is larger, such as a domestic operators group enterprise standards "in addition to the variable frequency power supply of the motor, single motor rated power is greater than 350 kw, appropriate USES 10 kv power supply".After power is supplied by high pressure water chiller can be compensated by a transformer and low and dense busbar, cable investment, the comprehensive factors compared to the price of high pressure water chillers, preliminary statistics can save 00750 RMB/kW (refrigerating capacity);High pressure oil machine concentrated to decorate, can according to the development stage, the power consumption of the park by investment, while low pressure oil machine can be to match the low with modular and regardless of the actual load rate of oil machine, waste oil machine investment;Promote the use of high pressure oil machine after ATS cabinet can reduce distribution in the low-voltage distribution system.
Above analysis shows that, in the low-voltage distribution system main function, measurement, capacitance, ATS cabinet can be replaced, such as the implementation of high pressure to the load center of secondary transformation than after obviously on the low voltage side can save more cost and decrease of the intermediate distribution after the reliability to improve a lot.
UPS system application status abroad
From the perspective of the UPS system development of Europe, medium voltage UPS system is used in industrial uninterruptible power supply application scenario, with megawatt power rating and up to 99.5% of the medium voltage UPS, energy storage and the inverter is still in low level, and it can greatly simplify the maintenance work and reduce the system cost.Modification of medium voltage UPS can be customized design, compatible with a wide variety of energy storage device, depending on the required for the protection of the time.Super capacitor and the flywheel can provide the high density protection within a few seconds, the battery can reach up to 15 minutes of spare time.
In North America early industrial medium-pressure type UPS system for container type structure or outdoor enclosure structure.Data centers use medium-pressure type UPS system for indoor type, modular structure and capacity of 2.0 MW ~ 20 MW.Including input/output switch cabinet, transformer, main control unit, PES ark (mp), bidirectional converter, energy storage box, etc.Outdoor storage box backup time is 1 ~ 3 minutes, indoor type backup time according to the requirements of customers, can reach more than 30 minutes.
As you can see, there have been similar products abroad, but foreign medium voltage UPS more aimed at to focus on the medium voltage UPS system function to solve, is now part of the large data centers in the United States began to application.
Is particularly worth mentioning is that compared to conventional low-voltage UPS, low pressure in the integration of UPS in the same scenario will reduce 80% of the cost of investment, and are able to bring about changes in the "incredible", mainly thanks to sharply reduce the traditional covers an area of low voltage power distribution cabinets, save a lot of low-voltage distribution busbar, cable, and generating sets with high pressure oil machine also facilitate investment by installments.Predictably, medium voltage UPS system for operators to save a lot of power supply and distribution costs, further enhance the market competitiveness of the operators.
