I. What is a Distribution System?

　　Once computer and network communication equipment is put into service, failure to establish a long-term, stable power supply system that ensures the reliable operation of such equipment and its associated peripherals will inevitably lead to serious political and economic consequences. Conventional power supply systems, which typically rely on a single power feed supplemented by generator sets, cannot provide dependable power assurance. A high-quality, efficient power distribution environment plays a crucial role within the data center. Therefore, data center power distribution is the “heart” of the entire facility and represents a key focus in data center engineering projects.

　　II. Data Center Power Distribution Requirements

　　1. The data center distribution cabinets shall be designed to provide accurate and reliable power supply to each circuit based on its intended application. This design proposes the use of two distribution cabinets—the utility power distribution cabinet and the UPS distribution cabinet—such that power-supply loads of different natures are not controlled within the same cabinet. A modular architecture is adopted to implement each distribution function, and spare circuits shall be provided in the distribution cabinets to accommodate future expansion of data center equipment.

　　2. The automatic air circuit breakers, contactors, fuses, disconnect switches, and other components selected for the distribution cabinet shall be reliable in performance, meet the design requirements in terms of technical specifications, and be capable of satisfying the operational requirements of computer equipment and its auxiliary devices.

　　3. The distribution cabinet shall be equipped with an emergency switch. In the event of a serious incident or an accidental fire in the entire computer room, the switch shall be capable of immediately disconnecting the power supplies to the computers, the air-conditioning system, and the fresh-air ventilation system.

　　4. Each branch circuit in the distribution cabinet shall be equipped with an indicator light to show the on/off status of the respective circuit.

　　5. Within the distribution cabinet, connection devices for the neutral conductor and the protective earth conductor shall be provided in accordance with the specific requirements of the computer equipment and its auxiliary devices. The neutral conductor, the protective earth conductor, and the enclosure of the distribution cabinet shall be electrically insulated from one another.

　　6. The busbars, grounding bars, and all cables, conductors, neutral wires, and grounding wires used inside the distribution cabinet must comply with national standards and be color-coded and numbered in accordance with national regulations.

　　7. Minicomputers, network equipment, and PC servers shall be supplied with power via separate, independent distribution circuits within the distribution cabinet.

　　III. Principles of Data Center Power Distribution Design

　　1. A dedicated power supply provides power exclusively to computers and network communication equipment.

　　2. A surge arrester must be installed on the distribution cabinet to protect against lightning strikes and switching transients in the power grid.

　　3. After the installation of the data center equipment system, three-phase balance must be considered.

　　4. Give due consideration to power supply frequency, voltage fluctuations, and the load-carrying capacity of the utility grid.

　　5. Power and lighting wires and cables shall, wherever possible, be routed along the ceiling using cable trays and galvanized steel conduits. UPS cables shall be shielded to minimize electromagnetic interference and routed beneath the floor; interference-suppression measures must still be implemented during installation.

　　6. This system employs reliable electrical bonding between the protective earth conductor and the metal enclosures of all equipment, cable trays, conduit, metal aluminum-plastic panels, and metal supports, with such bonding routed to the existing system grounding electrode. The grounding is reliable and complies with relevant code requirements.

　　7. Installation height of wall-mounted outlets: 300 mm above the finished floor. Installation height of switches: 1,400 mm above the finished floor.

　　8. In the equipment room, DC grounding shall be segregated from AC protective grounding: the DC grounding grid shall be connected to the building’s DC grounding electrode at an appropriate location, with the connection complying with relevant electrical requirements.

　　9. The wiring and cables for lighting, air conditioning, and maintenance shall be flame-retardant (ZR) double-insulated wires and cables. UPS cables shall be RVVP-grade cables. Interference-suppression measures shall be implemented during installation.

　　10. Lighting shall be provided by glare-free, reflective grille luminaires.

　　11. Design illuminance for the main computer room ≥ 400 lx; for auxiliary computer rooms ≥ 200 lx; and for emergency lighting ≥ 50 lx.

　　12. Prevent sudden power outages and surges in the power grid.

　　13. The power supply’s stability deviation shall not exceed ±5% of the rated value.

　　14. The power supply voltage shall have low ripple and minimal interference to prevent external electromagnetic interference from entering the system.

　　15. Do not connect the power supply system in parallel with high-capacity inductive loads to avoid high-voltage inrush currents.

　　16. Prevent frequency drift in the power grid.

　　17. Maintain a low-impedance grounding system.

　　IV. Essential Equipment for Data Center Power Distribution

　　1. Lighting System

　　Lighting shall be provided by luminaires matched to the suspended ceiling; grid-type luminaires are specified, with requirements for high illuminance and glare-free operation. Low-color-temperature, daylight-type fluorescent tubes are to be used. The illumination level in the equipment room shall be no less than 500 lx, while emergency lighting shall utilize grid-type luminaire panels with an illuminance requirement of no less than 50 lx. These grid luminaires must be equipped with high-quality electronic ballasts that deliver energy efficiency, excellent start-up performance, a high power factor, zero audible noise, and no flicker, ensuring no interference with computer power supplies. Luminaires shall be installed in a manner that is both functional and aesthetically pleasing, with careful attention to glare control. Automatic interlock control with the mains supply is to be employed. Emergency lighting shall be powered by both the mains and the UPS; in the event of a mains failure, the system shall automatically switch over to the UPS within the equipment room. Evacuation signage lights shall be installed at the main entrance, with an illuminance of no less than 0.5 lx.

　　2. UPS Uninterruptible Power Supply System

　　UPS systems employ IGBT power devices and multiple protection technologies, while advanced distributed direct parallel connection technology ensures online capacity expansion and system redundancy. The output stage incorporates an isolation transformer to effectively suppress third-harmonic distortion, providing robust overload and surge-impact resistance.

　　Regular automatic battery self-tests, backup time prediction, and intelligent battery management;

　　Supports multiple backend communication protocols, including RS-232, RS-485, SNMP, and MODEM. To accommodate future capacity expansion, the UPS units selected are designed to allow parallel operation regardless of differences in individual unit power ratings.

　　3. Auxiliary Power Supply and Distribution System

　　To prevent potential interference to the computer system caused by auxiliary electrical equipment operating within the data center, such equipment is typically supplied with power from a dedicated subsystem known as the auxiliary power distribution system. This system provides power to all ancillary equipment that supports the operation of the computer system, including air-conditioning units, maintenance equipment, fresh-air ventilation systems, lighting fixtures, test equipment, automatic fire-suppression systems, and auxiliary power outlets.

　　V. Characteristics of the Data Center Power Distribution System

　　1. Dual-bus power supply ensures high reliability of the power supply at the distribution system level.

　　2. Enables flexible and rapid deployment, simplifying data center power distribution.

　　3. The distribution equipment features hot-swappable capability, enhancing system reliability, maintainability, and scalability.

　　4. An intelligent monitoring and alarm system ensures high manageability and security of data center power distribution. The smart power distribution system enhances load reliability, extends the service life of power protection equipment, helps control the operational environment, and provides proactive disaster recovery solutions.

　　VI. Intelligent Management of Power Supply and Distribution Systems

　　(1) The intelligent monitoring system for the distribution board can monitor, alarm on, and statistically analyze the switch status and load conditions of the power distribution system.

　　(2) The electrical parameters monitored at the input end include: electric quantity, active power, reactive power, apparent power, power factor, three-phase voltage, current, and frequency, among others.

　　(3) The electrical parameters monitored on the output branch include: rated current, actual current, load percentage, harmonic distortion of the load current as a percentage, load energy consumption, and power factor, among others.