What Is an Electrical Substation?

A substation is a place in the power system that converts voltage and current, receives electrical energy, and distributes electrical energy. The substation in the power plant is a boost substation, and its role is to boost the power generated by the generator and feed it into the high-voltage grid.

(1) A type of substation. Refers to AC UHV stations, nuclear power, large energy bases (3 million kw and above) for delivery and cross-regional (North China, Central China, East China, Northeast, Northwest) contact 750/500 / 330kV substations.

(2) Type II substation. Refers to other than a class of substations, 750/500 / 330kV substations, substations delivered by power plants (1 million kW and above, below 3 million kW), and inter-provincial contact with 220kV substations, the main transformer or bus is shut down and the switch refuses to operate Transformer substations that cause grid events of level 4 and above.

(3) Three types of substations. Refers to 220kV substations other than Class II, substations delivered by power plants (300,000 kW and above, below 1 million kW), substations with main transformers or buses out of service, and switch refusal to cause five-level grid events, which are first-level and above Substations directly powered by important users.

(4) Four types of substations. Refers to substations of 35kV and above, except for Class I, II and III.

Note: All 220kV substations in the work area are three types of substations, and all substations below 110kV are four types of substations. ^[1]

The electrical equipment in the substation is divided into primary equipment and secondary equipment. The main equipment in the substation is briefly introduced below.

1. Primary equipment

Primary equipment refers to equipment that directly produces, transports, distributes and uses electrical energy, mainly including

The structural design and equipment layout of substations generally have the following requirements:

The auxiliary 10 kV substation on the ground floor of the building does not need to be divided into rooms, transformers and

The substation inspection is to observe the appearance of the equipment for irregularities through regular inspections, such as whether the color changes, whether there are foreign objects, whether the pointer indicates whether the equipment is normal, whether the equipment is normal, whether there are abnormal odors, and allowed to touch Whether the temperature of the equipment is normal, and measuring the changes in the operating parameters of electrical equipment during operation, etc., to determine whether the equipment's operating conditions are normal.

Substation inspection system is an effective measure to ensure the normal and safe operation of equipment. It is of great significance to reduce the occurrence of accidents and the scope of their impact by understanding the operating status of the equipment through regular inspections by the staff on duty, grasping the abnormal operation, and taking corresponding measures in a timely manner. To this end, the substation should work out the specific inspection methods based on the actual operating conditions of the operating equipment, and summarize past experiences and lessons learned from handling equipment accidents, obstacles and defects.

The inspection and inspection system should clearly define the inspection items and content, the cycle and the inspection route, and make clear signs. The inspection and inspection route shall be formulated according to the inspection area and contents of the equipment area and electrical equipment. Conditional substations should be equipped with the necessary inspection equipment. In peak load periods, infrared thermometers can be used for inspection. In addition, sufficient and good lighting should be ensured to provide the necessary conditions for equipment inspections. Special patrols at night, in bad weather and during special missions. To clarify specific inspection requirements and precautions, and to take necessary measures, special patrols must be attended by leaders on duty. After each inspection, the inspected equipment defects shall be recorded in the equipment defect record book, and the inspection personnel shall be responsible for the records. ^[4]

The substation must establish the following technical files.

(1) instruction manual of equipment manufacturer;

(2) Factory test records of electrical equipment;

(3) Installation and transfer of relevant materials;

(4) Records and reports of improvement and repair of electrical equipment;

(5) Overhaul of electrical equipment over the years and regular preventive construction reports;

(6) Special report on electrical equipment accidents, obstacles and operation analysis;

(7) Serious defects in electrical equipment, equipment changes, and modification records. ^[5]

Substations have emerged since the establishment of the first true power system. As an integral part of the power system, the substation has been developed with the power system for more than 100 years. In the development process of more than 100 years, Great changes have taken place in voltage levels and equipment conditions.

On the construction site of the substation, indoor substations and some underground substations gradually appeared from the original open outdoor substations. The area of the substations was much smaller than that of the original open outdoor substations.

On the voltage level, with the development of power technology, a small number of 110kV and 220kV substations have been used as hub substations. 35kV is a small grid transmission mode for terminal substations, and gradually developed into a large grid transmission mode with UHV 1000kV and 500kV substations as hub substations, and 220kV and 110kV substations as terminal substations.

In terms of electrical equipment, the primary equipment is mainly open outdoor equipment, and has gradually developed to fully enclosed gas combined appliances (GIS) and semi-enclosed gas combined appliances (HGIS); secondary equipment is protected and developed by early transistors and integrated circuits To microcomputer protection. ^[2]