Overview:
A substation is a place in the power system that converts voltage and current, receives and distributes electrical energy.
The substation in the power plant is a step-up substation, and its function is to boost the power generated by the generator and feed it to the high-voltage grid.
Classification:
(1) A class of substations. Refers to AC UHV stations, nuclear power, large-scale energy bases (3 million kw and above) outsourcing and inter-regional (North China, Central China, East China, Northeast China, Northwest China) liaison 750/500/330kV substations.
(2) Class II substations. Refers to other than Class I substations, 750/500/330kV substations, substations outside the power plant (1,000,000 kW and above, 3,000,000 kW) and inter-provincial liaison 220kV substations, the main transformer or bus is out of service, the switch refuses to operate. Substations that cause grid events of level 4 and above.
(3) Three types of substations. Refers to 220kV substations other than Category II, substations sent outside the power plant (300,000 kW and above, and below 1 million kW), and substations where the main transformer or busbar is out of service, and the switch refuses to actuate and causes a five-level power grid event. Substations that directly supply power to important users.
(4) Four types of substations. Refers to 35kV and above substations other than Category I, II and III. Note: All 220kV substations in the work area are Category III substations, and all substations of 110kV and below are Category IV substations.
Equipment:
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 equipmentPrimary equipment refers to the equipment that directly produces, transmits, distributes and uses electrical energy, mainly including transformers, high-voltage circuit breakers, isolating switches, bus bars, arresters, capacitors, reactors, etc.
2. Secondary equipment Secondary equipment in substations refers to equipment that measures, monitors, controls and protects the operating conditions of primary equipment and systems. It mainly consists of relay protection devices, automatic devices, measurement and control devices, metering devices and automation systems.
Development:
Substations have appeared since the establishment of the first real power system. As an indispensable part of the power system, substations have developed together with the power system for more than 100 years. Huge changes have taken place in terms of voltage levels and equipment conditions.
On the construction site of the substation, from the original all open outdoor substations, indoor substations and some underground substations have gradually appeared. Compared with the original open outdoor substations, the area of In terms of voltage level, with the development of power technology, a small number of 110kV and 220kV substations are used as pivot substations. 35kV is a small power grid transmission mode for terminal substations, and gradually develops into a large power grid transmission mode with UHV 1000kV substations and 500kV substations as pivot substations, and 220kV and 110kV substations as terminal substations.
In terms of electrical equipment, primary equipment is dominated by the original open outdoor equipment, and gradually developed to fully enclosed gas combined electrical appliances (GIS) and semi-closed gas combined electrical appliances (HGIS); secondary equipment is protected by early transistors and integrated circuits. to the microcomputer protection.
