5　Urban Distribution Network

5.1　General Provisions

5.1.1　For an urban distribution network，its structure and applied techniques（such as neutral point earthing mode and short-circuit current control level）shall be optimized，voltage level sequence reasonably arranged and equipment level continuously improved so as to render the network energy-saving，environmentally-friendly and smart.

5.1.2　Power supply capacities of distribution networks at all levels shall be designed with a proper margin.Main power supply lines and key distribution facilities should be one-off completed according to network plan.

5.1.3　The distribution networks should be constructed in a unified and standard manner.The specifications of conductors and cables，scales and types of substations and distribution stations，and capacity of main transformers of substations，and types of distribution facilities in the service area should be properly configured.Two or three types of distribution facilities may be specified for each voltage level as needed.

5.1.4　According to the development of network at the next higher voltage level，an urban distribution network shall be simplified and modified to avoid HV and LV electromagnetic loop networks.