GB 50052-2009 Code for Design of Power Supply and Distribution Systems

General Provisions

• 第 1.0.3 条The power supply and distribution system design shall ensure safety, reliability, economy, and applicability,…
• 第 1.0.4 条The design of the power supply and distribution system shall reasonably determine the load classification. Cl…
• 第 1.0.5 条Measures must be taken to prevent parallel operation between the emergency power supply and the normal power …
• 第 1.0.6 条The power supply and distribution system design should allow for future expansion and consider the possibilit…
• 第 1.0.7 条The design of the power supply and distribution system shall comply with the provisions of the relevant curre…
• 第 1.0.8 条The power supply and distribution system design shall meet power quality requirements, and indicators such as…

Terminology

• 第 2.0.1 条Grade I load: interruption of power supply will cause personal injury or death, major equipment damage or maj…
• 第 2.0.2 条Secondary load: Interruption of power supply will cause relatively large economic losses, disorder in public …
• 第 2.0.3 条Tier 3 load: electrical load that does not belong to Tier 1 or Tier 2.
• 第 2.0.4 条Emergency power supply: an independent power source that supplies power to particularly important loads withi…
• 第 2.0.5 条Standby power: the power source used to maintain non safety related loads when the normal power supply is int…
• 第 2.0.6 条Dual power supply: Two independent power sources; when either source fails, the other source can supply all o…
• 第 2.0.7 条Self provided power source: power generation equipment installed by the user, such as a diesel generator, use…
• 第 2.0.8 条Load classification: Based on the consequences of power supply interruption, loads are classified as Grade 1,…

Load classification and power supply requirements

• 第 3.0.1 条Power loads shall be classified as Grade I, Grade II and Grade III loads according to the reliability of powe…
• 第 3.0.2 条A Grade I load shall be supplied by two power sources; when one power source fails, the other power source sh…
• 第 3.0.3 条The power supply system for Grade II loads should preferably be supplied by two circuits. When the load is sm…
• 第 3.0.4 条Class III loads have no special power supply requirements and can be supplied by a single circuit.
• 第 3.0.5 条The operating time of the emergency power supply shall be determined according to the shutdown time required …
• 第 3.0.7 条In hotel buildings, Grade I loads include: computer systems for operation and management of large hotels, ban…

Power supply and electrical distribution system

• 第 3.0.1 条The power supply and distribution system should be simple and reliable, and the number of distribution levels…
• 第 3.0.2 条First class loads shall be supplied by two independent power sources; second class loads should be supplied b…
• 第 3.0.3 条For loads of special importance within the Class I load category, in addition to being supplied by two indepe…
• 第 3.0.7 条Measures must be taken to prevent parallel operation between the emergency power supply and the normal power …
• 第 3.0.9 条Loads of the standby power supply are strictly prohibited from being connected to the emergency power supply …
• 第 3.0.4 条【Special Provisions for Hotel Buildings】 In hotel buildings, Class I loads (such as fire fighting equipment, …

Voltage selection and power quality

• 第 3.0.1 条The selection of voltage levels for the power distribution system shall be determined based on the capacity o…
• 第 3.0.2 条When the installed capacity of electrical equipment exceeds 250 kW or the power supply distance exceeds 250 m…
• 第 3.0.3 条For impact loads and fluctuating loads (such as elevators and air conditioning compressors), the voltage fluc…
• 第 3.0.4 条Harmonic voltage limits: For the public utility grid, the total harmonic distortion of the harmonic voltage (…
• 第 3.0.5 条Three phase voltage unbalance: the negative sequence voltage unbalance at the point of common coupling shall …
• 第 3.0.6 条Special provisions for hotel buildings: For hotels with a large number of single phase loads (such as guest r…
• 第 3.0.7 条Voltage deviation: Under normal operating conditions, the permissible voltage deviation at the terminals of e…
• 第 3.0.8 条Power quality management: When harmonic currents exceed the limits specified in GB/T 14549, filtering devices…

Reactive power compensation

• 第 3.0.1 条For reactive power compensation, the principle of local balancing should be adopted first; when centralized c…
• 第 3.0.2 条For high voltage power supply consumers, the power factor shall be 0.9 or above; for low voltage power supply…
• 第 3.0.3 条When capacitor reactive power compensation devices are used, automatic switching devices shall be installed a…
• 第 3.0.4 条Applicable clause for hotel buildings: When the capacity of electrical equipment is large, the load is stable…
• 第 3.0.5 条Capacitor banks shall be provided with discharge resistors; the discharge time shall not exceed 3 minutes, an…
• 第 3.0.6 条Reactive power compensation devices shall be provided with overvoltage protection, overcurrent protection and…

Low-voltage power distribution

• 第 3.2.1 条A Grade I load shall be supplied by two independent power sources; when one source fails, the other source sh…
• 第 3.2.8 条The power supply system for Grade II loads should preferably be supplied by two circuits. When the load is sm…
• 第 3.3.1 条Measures must be taken to prevent parallel operation between the emergency power supply and the normal power …
• 第 3.4.1 条The distribution system shall be designed to meet the requirements of electrical equipment for power supply r…
• 第 3.5.3 条In a TN system, when the overcurrent protective device of a distribution circuit also serves as earth fault p…
• 第 3.6.2 条When a single phase three wire supply is used, the neutral conductor (N) and the protective conductor (PE) sh…

Distribution lines

• 第 3.2.1 条Class I loads shall be supplied by two independent power sources; when one source fails, the other shall not …
• 第 3.2.2 条The power supply system for secondary loads should preferably be supplied by two circuits. When the load is s…
• 第 3.2.3 条Class III loads have no special power supply requirements and can use a single circuit supply.
• 第 3.3.1 条The type of emergency power supply should be selected according to the permitted power supply interruption ti…
• 第 3.4.1 条The power distribution system should be simple and reliable, with no more than two levels of distribution at …
• 第 3.4.5 条In hotel buildings, Class I loads such as fire protection equipment, emergency lighting, and guest room light…

Power distribution equipment layout

• 第 3.2.1 条The substation should be located close to the load center with convenient incoming and outgoing cable routing…
• 第 3.2.3 条The clear distance between the distribution equipment in the substation and the roof shall not be less than 0…
• 第 3.3.1 条Operating aisle width for LV distribution cabinets: fixed type single row not less than 1.5 m, double row not…
• 第 3.4.2 条The installation location of power distribution equipment should be well ventilated, with an ambient temperat…
• 第 3.5.1 条Height of the bottom of distribution cabinets (boxes) above floor level: not less than 1.2 m for surface moun…
• 第 3.6.3 条The enclosure protection rating of power distribution equipment shall not be lower than IP2X; in humid areas …
• 第 3.7.2 条When distribution lines penetrate fire compartments, they shall be sealed with firestop materials, and the fi…
• 第 3.8.1 条Metal enclosures and supports of power distribution equipment shall be reliably grounded, with a grounding re…

Special spaces

• 第 3.2.1 条A Grade I load shall be supplied by two power sources; when one power source fails, the other power source sh…

Special areas

• 第 3.2.3 条Particularly important loads within the Class I load category shall, in addition to being supplied by two pow…
• 第 3.2.8 条The power supply system for secondary loads should preferably be supplied by two circuits; when the load is s…
• 第 6.0.1 条Emergency power sources shall be selected according to the permissible power supply interruption time and sha…
• 第 6.0.2 条The power supply duration of the emergency power source shall comply with the following provisions: for emerg…
• 第 7.0.1 条Fire water pumps, fire elevators, smoke control and exhaust facilities, and other fire protection electrical …

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