Application of Generator Sets in Data Centers

In today's era of rapid digital development, data centers have become indispensable infrastructure across industries. Whether in finance, the internet, or government institutions, the massive demand for data storage and processing relies on the stable operation of data centers. Behind this, generator sets, as critical emergency power sources, silently ensure the electricity supply of data centers, and their importance is self-evident. This article will delve into the application of generator sets in data centers, and how to select and maintain generator sets to ensure reliable operation of data centers.

Data centers are not simply computer rooms; they are a collection of complex and precise facilities. In addition to core equipment such as computer systems, communication systems, and storage systems, they also include redundant data communication connections to ensure stable and secure data transmission; environmental control equipment to maintain suitable temperature and humidity within the computer room, creating an ideal operating environment for servers and other equipment; monitoring equipment to track equipment operating status and environmental parameters in real time, promptly detecting and addressing potential issues; and various security devices, such as fire prevention, theft prevention, and anti-static measures, comprehensively safeguarding data center security.

Take the financial industry as an example. With rapid development in recent years, the requirements for information storage and processing capacity have grown exponentially. From bank account management and transaction processing to data analysis and risk assessment in securities markets, every financial service relies on efficient management and precise analysis of massive information. As a platform supporting these information-based applications, the importance of data centers is increasingly evident. Once a data center experiences a power failure, the consequences of data loss would be catastrophic, potentially leading to interrupted financial transactions, customer information leaks, market chaos, and a series of serious problems. Therefore, the stability and reliability of the power supply are key guarantees for data center operation, and the importance of emergency power systems is self-evident.

In the power guarantee system of data centers, diesel generator systems are widely used as one of the emergency power sources. When sudden events such as municipal power outages occur, the data center's UPS (uninterruptible power supply) or high-voltage DC backup batteries immediately discharge to provide temporary power support for IT equipment, maintaining continuity of supply. Meanwhile, diesel generator sets start rapidly and complete parallel operation, providing continuous and stable power for the entire data center to ensure normal operation is unaffected.

Proper configuration of diesel generator sets is crucial for uninterrupted power supply in data centers. During the early design and planning stages of the data center, diesel generator sets need to be carefully configured based on the capacity of the incoming municipal power, serving as disaster recovery emergency power backup. For example, the largest domestic data center of the Agricultural Bank of China adopts a dual-bus redundant parallel system and auxiliary emergency power system, following the Uptime Institute Tier 4 construction standard. Kansen Diesel provided comprehensive planning and design for its emergency power system, covering emergency distribution systems, comprehensive protection systems, parallel operation systems, automatic control systems, auxiliary operation systems (fuel supply, ventilation), and computer room noise control systems, providing a safe and reliable emergency power system solution and strongly ensuring the disaster recovery capability of the data center.

As important emergency equipment in data centers, daily maintenance and upkeep of generator sets cannot be ignored. Proper maintenance not only extends the service life of the generator set but also ensures stable and reliable operation when needed.

First, regarding the maintenance of the generator set itself, shutdown under load is strictly prohibited. Before each shutdown, the load must be gradually disconnected, then the generator output switch turned off, and finally the diesel engine should run at idle for about 3–5 minutes before stopping. This procedure helps reduce engine wear and protect normal engine operation.

Second, the daily maintenance and upkeep of load banks are also very important. Load banks play a critical role during generator set testing and operation, but because they generate high temperatures and are high-voltage live components, special care is required. To avoid exposure to sun and rain, protective covers are usually installed on the load bank, but this also requires annual waterproofing and rust-proofing. Additionally, as the internal temperature of the load bank is high during operation and the enclosure is not completely sealed, rainwater can enter through cooling vents, causing excessive moisture inside and potentially reducing the insulation of the resistance wires over time. Therefore, in addition to waterproofing and rust prevention, regular maintenance of load banks, including internal dust removal, component inspection, and insulation monitoring, is necessary to ensure safety and reliability.

With rapid development in internet technology, the scale and data processing volume of data centers continue to increase, leading to increasingly diverse generator set requirements. When selecting generator sets, multiple factors need to be considered to ensure they match the actual needs of the data center.

The stability of the main grid is an important factor affecting generator selection. If the main grid is highly reliable, the data center's dependence on the generator set is relatively low, and a generator with slightly lower standby power can be selected as emergency power. Conversely, if the main grid has certain instability, a larger and more reliable generator is needed to ensure continuous stable power during grid failures.

Budget limitations are also an important factor. The purchase cost, installation cost, and maintenance cost of the generator set all need to be considered. While meeting the data center's power needs, a cost-effective generator set can ensure normal operation while avoiding unnecessary expenditure.

Different data centers store and process data with varying sensitivity, resulting in different tolerances for power interruptions. For data centers handling highly sensitive data such as financial transactions or medical information, power interruptions may cause serious consequences, requiring highly reliable and available generator sets. These data centers should select generator sets that meet Uptime Institute Tier III or IV standards to ensure continuous and stable power supply during main power failures, protecting data security and real-time accessibility. For data centers with lower data sensitivity, such as certain internal data centers of small enterprises, Tier I or II generator sets can be selected as backup power to reduce costs.

The Uptime Institute is an internationally recognized organization that sets standards and certifications for the design, construction, and operation of data centers, classifying them into four tiers: Tier I, II, III, and IV. The number of systems providing continuous and emergency power is a key factor in determining the tier.

Emergency power meeting Tier I or II standards mainly addresses short-term outages, with relatively smaller generator capacity and shorter operation time. Backup power meeting Tier III or IV standards requires generator sets capable of providing continuous and stable electricity during main power failure, without time limits. Therefore, for Tier III and IV data centers, generator capacity must be sufficient to operate stably at required load levels for extended periods.

When selecting a generator, the engine's COP (Continuous Operating Power) is an important reference. COP power is usually 80–90% of the rated power. However, choosing generator capacity based solely on COP may increase engine cost, installation space, and cooling requirements, and prevent the engine from operating at its most efficient load (around 100% power). To address this, major engine manufacturers in the generator industry introduced a new power definition, Data Center Continuous Power (DCC).

The DCC definition differs from traditional power ratings, allowing engines to operate continuously. After statistical analysis of failure probabilities and considering current equipment usage, manufacturers found that in countries with stable grids, emergency generators are rarely operated, and each run is short. Therefore, engines can operate at higher loads. Although engines cannot sustain PRP (Prime Rated Power) indefinitely, manufacturers use the DCC definition to ensure engines are not limited by duration or average load, enabling DCC-designed generators to meet Tier III and IV requirements as backup power.

However, DCC use is conditional, suitable only where main power failure probability is low. Manufacturers limit DCC use to countries with stable grids, sometimes requiring reference to recognized stable grid lists. If the main grid is sufficiently reliable, or data sensitivity is low, or real-time data access is not strictly required, the effective availability of facilities may decrease, classifying them as Tier I or II, where generators can be selected based on standby power to reduce installation costs.

The characteristics of generator sets and components used in data center projects are generally similar to other backup units, but stricter in some areas. The engine is the core component, as power generation depends on it. Engines for DCC projects must have electronic governors to quickly adjust voltage and frequency upon grid failure and maintain stability during operation.

When determining engine capacity, factors specific to data center applications, as well as general environmental conditions such as temperature and altitude, must be considered. For data centers with strict reliability requirements, selecting the starting system is crucial. Choosing maintenance-free batteries capable of providing sufficient starting power is important. Additionally, for rapid startup and quick load acceptance, heating the engine coolant with a resistance heater ensures optimal engine temperature during grid failure. A pump can assist circulation for uniform coolant temperature, and pre-lubrication via an oil pump improves startup speed.

The generator is another key component. A high-performance AVR (Automatic Voltage Regulator) keeps voltage fluctuation below 0.5%; properly designed windings maintain low harmonic distortion and EMI. PMG (Permanent Magnet Generator) provides independent power to the AVR for reliable operation under sudden load. High-quality varnishing, IP23 protection, and moisture heaters are essential for continuous operation, especially in high-humidity environments.

In some data center installations, generator sets are placed on lower floors or underground with limited airflow, making cooling system selection critical. Experienced engineering teams design intermediate coolers and secondary circuits or remote cooling systems for upper floors or rooftops to ensure effective heat dissipation under limited ventilation.

Generator sets, as emergency power sources for data centers, play a critical role in ensuring stable operation. Proper selection, configuration, and maintenance guarantee continuous and stable operation during main power failure, preventing data loss and service interruptions. When choosing a generator, multiple factors must be considered, including main grid reliability, budget, data sensitivity, and Uptime Institute tier requirements. Attention to key component characteristics such as engine electronic governors, starting systems, generator AVR, winding design, and cooling systems can further improve performance and reliability. With technological advancement, generator sets are evolving toward higher efficiency, energy-saving, and intelligent operation, providing increasingly reliable power for the future of data centers.

In summary, generator sets are indispensable power guardians of data centers. Only by fully recognizing their role in data center operations can data centers operate stably and efficiently in the digital era, supporting enterprises and society in digital transformation.