Which of the following descriptions is part of power system design? ( )

Article 3.0.6 of the Technical Regulations for Power System Design (GB/T 5429-2009) stipulates that the specific tasks of power system design are:

①Analyze and put forward the level, distribution, and composition of the demand for electric power and its characteristics. ② Conduct power, power balance, and further demonstrate the reasonable power supply range of the system and the corresponding networking program, power supply construction program and system peak adjustment program. ③ Demonstrate the grid construction program, including voltage level, grid structure and transition measures. ④ Carry out system electrical calculation and put forward technical measures to ensure voltage quality, system security and stability. ⑤ Propose the commissioning time, main equipment quantity and main specifications of generation, transmission and substation projects and reactive power compensation projects, and carry out investment estimation. ⑥Propose topics for further study.

The above tasks can be carried out in targeted phases according to the specific situation and on the basis of overall integration.

D, the calculation of the load of the electrical system used in the substation and the determination of the capacity of the transformer used is not part of the power system design.