电力系统的熟悉电力系统的形成和发展，掌握电力系统的组成和生产过程及电力系统的基本参量和接线图；了解掌握我国电力系统基本情况。

Today's power networks are based on large central power stations via high voltage transmission systems, which is then distributed in medium/low-voltage local distribution systems.

The transmission and distribution systems are commonly run by a monopoly national or regional body. In contrast, the generation sector is increasingly competitive. The overall power still flows in one direction from the transmission system, to the final customers via distribution systems. The power is typically dispatched centrally by the generating companies, and network control is set by predetermined actions from the grid dispatch center (s). There is little or no consumer participation and no end-to-end communication.

Traditional network design was based on the ideas of economies of scale in large centralized generation and the geographical distribution of generation resources (locations near coalfields, cooling water, etc). The grids were optimized for regional self-sufficiency. Interconnections were originally developed for mutual support between regions, but now are increasingly being used for trading between areas. The transmission grid provides an arena that has traditionally enabled centralized economic optimization and enhances the overall security of supply. The existing grid system provides an excellent foundation from which future challenges and opportunities can be met. However, by necessity this requires incremental rather than evolutionary change and so the need for a long-term strategy is overwhelming.

在此基础上引入我国电力系统的电压等级，并通过讲授使学生掌握我国电力系统的电压等级；

 Functions of power transmission

     The function of power transmission is to send power from power plants to load center or to exchange power between power networks in order to attain the generation-consumption balance or the supply-demand balance between power networks. Power transmission is completed by step-up substations, step-down substations and connected transmission equipment. The transmission line mainly consists of the transmission conductors (cables), poles or towers, insulators, overhead ground wires, and grounding devices. The transmission at high voltage can reduce the line loss and the voltage drop, ensure the power quality, raise the economy of power network operation. The increase of transmission line voltage can not only raise the amount of transmitted power, but also reduce the line loss and line voltage drop, and improve the voltage quality.

Voltage classes

     The transmission voltage can be divided into high voltage, extra-high voltage and ultra-high voltage. Specifying the standard voltage classes for power systems is to satisfy the seriated voltage demand in the manufacture of power equipments and to facilitate reasonable choice of transmission voltage corresponding to specific transmitting capacity and distance. The specified rated voltages (line voltage effective value, in kV) of power system in our country are: 0.38, 3, 6, 10, 35, 110, 220. 330, 500, 750, 1000kV

     In our country, 110kV and 220kV voltage class power networks are called high voltage (HV) networks. The extra-high voltage (EHV) power network refers to 330kV, 500kV and 750kV voltage class power networks. The ultra-high voltage (UHV) power network refers to 1000kV AC and +800kV DC and above voitage class power networks.

Power network is that part of the electric power system but the generators and the consumers, including substations, transmission lines and distribution networks. The function of an electric power network is to connect the generating stations with the customers and with the minimum disturbance to transfer this power over transmission lines and distribution network, with the maximum efficiency and reliability to deliver power to consumers at virtually fixed voltage and frequency. Based upon operating voltage, power network can be divided into transmission system and distribution system. Transmission can be classified into high voltage (HV) extra-high voltage (EHV) transmission and ultra-high (UHV) voltage transmission. Voltages above 220kV are usually referred as EHV, and those above 800kV are referred to as UHV Electric power is transmitted at possible high voltage level either because of transmission distance or because of the amount of transmitted power, or because of their combination.

The loads supplied by power system may be classified into industrial loads and domestic loads. They differ from each other in service requirements and in the facilities needed to supply them. In industrial loads there is high proportion of induction motors. Small industrial loads are supplied by the primary feeders. However, the large industrial loads are usually served from "customer" substations and a very large factory load may require several substations and may be fed from transmission system. Such customer substations require special consideration as to transformer size, connection, location, spare capacity, emergency operating requirements, service continuity, provisions for load growth and system neutral grounding. Domestic loads comprise commercial loads and residential loads. Domestic loads consist largely of lighting, air conditioning and household device loads. Domestic loads are supplied by distribution system.

国家能源局：我国建成全球规模最大电力系统，发电装机达到24.7亿千瓦。
9月26日，国家能源局规划司副司长宋雯表示，我国建成全球规模最大的电力系统，发电装机达到24.7亿千瓦，超过G7国家装机规模总和；35千伏及以上输电线路长度达到226万公里，建成投运特高压输电通道33条，西电东送规模接近3亿千瓦，发电装机、输电线路、西电东送规模分别比十年前增长了1.2倍、0.5倍、1.6倍。

国家能源局：到2025年西电东送能力达到3.6亿千瓦以上，全国油气管网规模达到21万公里左右，建设山西、蒙西、蒙东、陕北、新疆五大煤炭供应保障基地。

3.“十四五”期间，四川规划新建电源项目210个，计划总投资4289亿元。到2027年，预计四川电力总装机达1.98亿千瓦左右，较目前新增电力装机约9523万千瓦。

2022年9月27日，中国华能集团有限公司上都百万千瓦级风电基地首批机组成功并网。华能上都百万千瓦级风电基地是我国首批大型新能源基地项目之一，也是华能首个“风光火储”耦合发电的基地型规模化综合能源项目，总投资108亿元，建设200万千瓦风电和30万千瓦储能电站，建成后每年可为京津唐地区输送清洁电力65亿千瓦时，相当于减排二氧化碳约400万吨。