What you need to consider when designing power supply for data centers

At the end of 2018, the Digital Economy program was approved, according to which it is planned to deploy an internal infrastructure for collecting, processing, storing and providing data in Russia. This means that in the coming years the number will increase in the country. specialized data centers, or data processing centers (DPC), and the demand for electrification of such facilities will increase.

The main difficulty is that domestic standards for power supply of data centers are under development (now experts use the American standard TIA 942 and PUE). The construction of data centers in Russia is developing, but despite the growing experience in this area, engineers are faced with rather difficult issues.

The first task. Data Center Power Redundancy

Where is the problem? The TIA 942 standard identifies four levels of data warehouse reliability: Tier I, II, III, and IV. The first two are considered not very reliable, so they are not used for more or less large data centers.

• Tier III is the most common and sufficient level. According to it, 1.6 hours of downtime per year are allowed, and the failover ratio should be 99.982%.

• Tier IV is an ideal level for all data centers with a fully fault-tolerant infrastructure, only 24 minutes of downtime are allowed.

Due to such high requirements (even at the Tier I level), the rules for the installation of electrical installations classify the data center as objects of the first category in terms of reliability of power supply, that is, there must be two independent power sources. It is required not only to select these sources, but also to ensure prompt switching between them in the event of an accident.

Decision. As a rule, either different transformer substations or different sections of one substation are used. In addition, there is equipment in the data centers, interruptions in the functioning of which are unacceptable for even a second (receivers of a special group), uninterruptible power supplies are installed in this case. A diesel engine provides data center operation if both network sources are disconnected.

Equipment. It is necessary to provide for fast switching between sources using automatic reserve entry systems. When developing an ATS circuit, it is important to consider the capacity of the supply transformer and the power of the energy source of the parallel system. Without these parameters, it may turn out that switching to a backup circuit will disable it, since the power source will not cope with the total load.

The ABP system should operate once for the shortest possible time after switching off the working energy source. To implement the circuit taking into account the indicated conditions, it is recommended to use power contactors for switching current up to 500 A, for example, electromagnetic three-pole devices of the KTI series from IEK.

The ABP system is also equipped with circuit breakers with the ability to connect additional trip units and electric drives. The latter are presented in the VA88 IEK series, they work with voltages up to 400 V and are designed for currents up to 1600 A. You can use BA07 devices of the same brand, on the basis of which there is an option to solve a fully finished sectional cell with a mechanical switch-on lock.

The second task. Maintaining the efficient operation of refrigeration and air conditioning systems

Where is the problem? Computer equipment generates such an amount of heat that can affect the efficiency of the data center and disrupt the functioning of the main equipment. Therefore, when creating a data center, powerful ventilation and air conditioning systems are required, which absorb a lot of electricity.It is important for engineers to lay elements in the project that increase the energy efficiency of cooling equipment.

Decision. The controlled operation of the machines should be ensured: the system should independently monitor the climatic parameters in the halls and include, if necessary, fans and compressors.

Equipment. Given the size of the data center and the amount of equipment in them, designing an automation system based on individual components (frequency converters, high-precision thermal sensors, inverter compressors, etc.) is laborious and fraught with errors.

It is better to use integrated solutions from the field of industrial automation - for example, ONI systems provide typical options for ensuring the operation of supply and exhaust ventilation.

The system is integrated with IEK GROUP products and includes a controller, frequency converter, software, automation cabinet, instrumentation.

If necessary, you can supplement the solution with any components: the engineer needs to send the corresponding technical task with a list of the desired equipment to the manufacturer.

The third task. Protect data center equipment from accidents in electrical networks inside the building

Where is the problem? High-tech computer equipment does not have high electrical resistance, it must be protected from overvoltage, short circuit currents and switching. Even pick-ups (for example, from turned on air conditioners) or higher harmonics of the current can damage the electronics or introduce errors into the data.

Decision. To protect the equipment in electrical panels, modular protective and switching devices are installed - circuit breakers, disconnectors, load switches, residual current circuit breakers, etc.

Equipment.

• Circuit breakers must be selected with characteristic C or D according to the cutoff currents. The first ones provide reliable protection of circuits and equipment with a cut-off of 5 ÷ 10, the second are designed to start and protect against overcurrents of industrial motor wiring, the cut-off of the circuit breaker is 10 ÷ 14.

• Differential circuit breakers and residual current circuit breakers in computer networks must respond not only to variables, but also to pulsating fault currents, so instead of the usual devices of type AC, type A should be used. Differential and ordinary circuit breakers with the necessary characteristics are presented in the IEK ranges: you can choose solution for any amperezh, with a different number of poles and breaking capacity.

• Surge protection must be provided in the mains.

• All switching devices are selected taking into account selectivity.

The data center is a complex and high-tech construction, where the quality and reliability of even the smallest elements matter.

Material prepared by the press service of IEK GROUP