一、什么是电气一次，二次？

First, what is electrical primary and secondary?

体现在电气一次设备与二次设备的区别上：

It is reflected in the difference between electrical primary equipment and secondary equipment:

一次设备是指直接用于生产、输送和分配电能的生产过程的高压电气设备。它包括发电机、变压器、断路器、隔离开关、自动开关、接触器、刀开关、母线、输电线路、电力电缆、电抗器、电动机等。

Primary equipment refers to high-voltage electrical equipment that is directly used in the production process of producing, transporting and distributing electrical energy. It includes generators, transformers, circuit breakers, disconnectors, automatic switches, contactors, knife switches, busbars, transmission lines, power cables, reactors, motors, etc.

由一次设备相互连接，构成发电、输电、配电或进行其他生产过程的电气设备称为一次设备。

Electrical equipment that consists of primary devices connected to each other to make up power generation, transmission, distribution or other production processes is called primary equipment.

二次设备是指对一次设备的工作进行监测、控制、调节、保护以及为运行、维护人员提供运行工况或生产指挥信号所需的低压电气设备。如熔断器、控制开关、继电器、控制电缆等。

Secondary equipment refers to the low-voltage electrical equipment required for monitoring, controlling, regulating, protecting the work of primary equipment and providing operating conditions or production command signals for operation and maintenance personnel. Such as fuses, control switches, relays, control cables, etc.

由二次设备相互连接，构成对一次设备进行监测、控制、调节和保护的电气设备称为二次设备。

Electrical equipment that is connected to each other by secondary equipment and constitutes a primary equipment for monitoring, controlling, regulating and protecting is called secondary equipment.

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二、电气一次的分类

Second, the classification of electrical primary

电气一次设备根据其在生产中的作用可以分为六大类：

Electrical primary equipment can be divided into six categories according to its role in production:

（1）生产和转换电能的设备。如发电机将机械能转换为电能、电动机将电能转换成机械能、变压器将电压升高或降低等，以满足输配电需要。

(1) Equipment for producing and converting electrical energy. For example, the generator converts mechanical energy into electrical energy, the motor converts electrical energy into mechanical energy, and the transformer raises or lowers the voltage to meet the needs of power transmission and distribution.

（2）接通或断开电路的开关电器。如断路器、隔离开关、熔断器、接触器等。它们用于电力系统正常或事故状态时，将电路闭合或断开。

(2) Switch electrical appliances that turn on or off the circuit. Such as circuit breakers, disconnectors, fuses, contactors and so on. They are used to close or disconnect circuits when the power system is in a normal or accident state.

（3）限制故障电流和防御过电压的电器。如限制短路电流的电抗器和防御过电压的避雷器等。

(3) Electrical appliances that limit fault current and defend against overvoltage. Such as an reactor that limits the short-circuit current and a lightning arrester that protects against overvoltage.

（4）接地装置。它是埋入地中直接与大地接触的金属导体及与电气设备相连的金属线。无论是电力系统中性点的工作接地或保护人身安全的保护接地，均同埋入地中的接地装置相连。

(4) Grounding device. It is a metal conductor buried in the ground that is in direct contact with the earth and a metal wire connected to electrical equipment. Whether it is the working grounding of the neutral point in the power system or the protective grounding to protect personal safety, it is connected to the grounding device buried in the ground.

（5）载流导体。如裸导体、电缆等。按设计要求，将有关电气设备连接起来。

(5) Current-carrying conductor. Such as bare conductors, cables, etc. As required by the design, the electrical equipment in question is connected.

（6）交流电气一、二次之间的转换设备。如电压和电流互感器，通过它们将一次侧的电压、电流转变为二次系统。

(6) AC electrical conversion equipment between the first and second times. Such as voltage and current transformers, through which the voltage and current on the primary side are converted into a secondary system.

三、电气二次回路小分类

Third, the electrical secondary circuit small classification