This part of the scope GB 12668 specifies the electromagnetic compatibility (EMC) requirements for electrical drive systems (PDS). The definition of PDS is described in 3.1. The electrical transmission system here includes variable speed AC motor drive and DC motor drive. These EMC requirements are specified for PDS with effective values of input and/or output voltage (line voltage) of converters below 35kV AC. The PDS referred to in this section refer to those installed in residential, commercial, and industrial locations, but excluding traction applications and electric vehicles. PDS can be connected to industrial or public distribution networks. The industrial power grid is powered by a dedicated distribution transformer, which is usually located within or near the industrial area and only supplies power to industrial users. The industrial power grid can also be powered by its own power generation equipment. In addition, the PDS can be directly connected to the low-voltage public power grid, which also supplies power to civilian use, where the neutral line is usually grounded. This section is related to EMC and covers different types of PDS with power ranging from hundreds of watts to hundreds of megawatts. PDS is often contained within a larger system. The content related to the system is not covered in this section, but guidance is provided in the informative appendix. These requirements are chosen to ensure sufficient electromagnetic compatibility (EMC) for PDS in residential, commercial, and industrial locations. However, these requirements cannot include extremely rare situations that may occur. The changes in PDS electromagnetic compatibility performance caused by fault conditions were not considered. The purpose of this section is to determine the limit values and test methods of PDS based on its intended use. This section includes requirements for anti-interference and electromagnetic emission prevention. Note 1: Electromagnetic emissions may cause interference with other electronic devices (such as radio receivers, measurement and computing equipment), and the requirement for immunity is to protect the equipment from continuous and terminal conductivity and radiation disturbances (including electrostatic discharge). For anti emission and immunity requirements, balance should be maintained between them based on the actual environment of the PDS. This section establishes the minimum requirements for electromagnetic compatibility of PDS. The immunity requirements are based on environmental classification regulations. The requirements for preventing low-frequency emissions are determined based on the nature of the power grid, while the requirements for preventing high-frequency emissions are determined based on four categories of intended use, involving both the environment and operation. This section is applicable to the evaluation of PDS. It can also be used to evaluate separately sold CDM or BDM (see 3.1). This section includes: - compliance evaluation requirements for products to be launched on the market; -- Recommended engineering design practices for situations where high-frequency emissions cannot be measured before the device is put on the market (such PDS is defined as C4 in 3.2.6). Note 2: The first edition (i.e. 2003 edition) of this section has already determined that the intended use may require engineering design for operation. This work is completed through the "restricted sales method". In the past, the "restricted sales method" often covered devices, which were covered by C2 and C4 categories (see 3.2) in the second version (i.e. this version). This section will serve as the complete EMC product standard, and EMC compliance evaluation will be conducted for C1, C2, and C3 products (see 3.2.3-3.2.5) when they are launched on the market