Design Code for User Electrochemical Energy Storage System

This document is the official Chinese electric power industry standard DL/T 5903-2025, titled 'Design code for user electrochemical energy storage system.' Issued by the National Energy Administration on September 28, 2025, and effective from March 28, 2026, it provides comprehensive design guidelines for user-side electrochemical energy storage systems. The code covers seven chapters: general provisions, terms, basic requirements, grid connection, selection and layout of energy storage equipment, architecture and structures, and energy conservation and environmental protection. Key technical aspects include primary system design, relay protection, electrical energy metering, power quality, battery and battery management system specifications, power conversion systems, monitoring and control, grid connection devices, cable selection, lightning protection, and auxiliary systems. The standard was developed under the supervision of the China Electricity Council and SAC/TC 550, with Shanghai Electric Power Design Institute as the chief editorial unit and contributions from industry partners like Huawei Digital Energy and Shenzhen Kstar New Energy. It serves as a mandatory reference for engineers and stakeholders involved in designing safe, efficient, and compliant user electrochemical energy storage installations.