A transformer station is a place in a power system that transforms voltage and current, receives electric energy and distributes electric energy. The transformer station in the power plant is a step-up transformer station, whose function is to boost the electric energy generated by the generator and feed it to the high-voltage grid.
1. Classification of transformer stations
1.1 Class I transformer station. Refers to AC UHV stations, nuclear power, large-scale energy bases (3 million kw and above) transmission and trans-regional (North China, Central China, East China, Northeast, Northwest) liaison 750/500/330kV transformer station.
1.2 Class II transformer station. Refers to transformer stations other than Class I transformer stations, 750/500/330kV transformer stations, power plant external transmission transformer stations (1 million kW and above, 3 million kW below) and inter-provincial contact 220kV transformer stations, main transformers or busbars out of service, switches refused to move transformer stations that cause level 4 and above grid incidents.
1.3 Three types of transformer stations. Refers to 220kV transformer stations other than Category II, power plant external transmission transformer stations (300,000 kW and above, below 1,000,000 kW), transformer stations where the main transformer or busbar is out of service, and the switch refuses to move, resulting in a level-5 power grid event, which is a level-1 and above transformer stations directly supplying power to important users.
1.4 Four types of transformer stations. Refers to 35kV and above transformer stations other than Category I, II, and III.
Note: All 220kV transformer stations in the work area are Class III transformer stations, and all 110kV and below transformer stations are Class IV transformer stations.
2. Transformer station equipment
The electrical equipment in the transformer station is divided into primary equipment and secondary equipment. The following is a brief introduction to the main equipment in the transformer station.
2.1 Primary equipment
Primary equipment refers to equipment that directly produces, transmits, distributes and uses electric energy, mainly including transformers, high-voltage circuit breakers, disconnectors, busbars, lightning arresters, capacitors, reactors, etc.
2.2 Secondary equipment
The secondary equipment of the transformer station refers to the equipment that measures, monitors, controls and protects the operating conditions of the primary equipment and system. It mainly consists of relay protection devices, automatic devices, measurement and control devices, metering devices, automation systems and secondary A DC device that provides power to the secondary device.
3. Layout requirements of transformer stations
The structural design and equipment layout of the transformer station generally have the following requirements:
3.1 The auxiliary 10 kV transformer station on the ground floor of the building does not need to be divided into rooms. Transformers and high and low voltage switchgears can be arranged in the same room on the same floor, and only need to maintain a specific distance. The 35 kV independent transformer station with a dedicated building should be arranged according to functional layers and divided rooms;
3.2 The indoor layout of the transformer station should be compact and reasonable, which is convenient for operators to operate, overhaul, test and inspect. The installation position of the switchgear should meet the minimum channel width requirements, and the development and expansion requirements should be properly considered;
3.3 Transformer station arrangement transformer station should reasonably arrange the location of each functional room in the transformer station. The high-voltage power distribution room is adjacent to the high-voltage capacitor room, the low-voltage power distribution room is adjacent to the transformer room, the low-voltage power distribution room should be convenient for outgoing lines, and the location of the control room should be convenient for operators work and management;
3.4 The facilities in the high and low voltage power distribution room should meet the safety and fire prevention requirements, and combustible materials are not allowed to be used for decoration in the station;
3.5 The doors of high and low voltage power distribution rooms, capacitor rooms and transformer rooms should open outwards, and the doors of two adjacent power distribution rooms should open in both directions;
3.6 The high and low voltage power distribution room, capacitor room, transformer room and main control room should be equipped with facilities to prevent rain, snow, snakes, rats, etc. from entering the room through doors, windows and cable trenches.
4. Transformer station inspection
The inspection of the transformer station is that the personnel on duty observe whether there is any abnormality in the appearance of the equipment through regular inspections, such as whether there is any change in color, whether there are sundries, whether the needle indication is normal, whether the sound of the equipment is normal, whether there is any abnormal smell, and whether it is allowed to touch Whether the temperature of the equipment is normal, measure the changes of the operating parameters of the electrical equipment during operation, etc., to judge whether the operating status of the equipment is normal.
Transformer station patrol 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 their scope of influence through the regular inspections of the on-duty personnel to understand the operating conditions of the equipment, grasp the abnormal operation, and take corresponding measures in a timely manner. For this reason, the transformer station should formulate specific inspection methods based on the actual working conditions of the operating equipment and summarizing the experience and lessons of dealing with equipment accidents, obstacles and defects in the past.
The patrol inspection system should clearly stipulate the items and content of the inspection, the cycle and the route of the patrol inspection, and make obvious signs. The inspection tour route should be formulated according to the inspection items and contents of the equipment area and electrical equipment. Conditional transformer stations should be equipped with necessary inspection tools. In the peak load period, infrared thermometers can be used for inspection. In addition, sufficient and good lighting should be ensured to provide necessary conditions for equipment inspections. During special inspections at night, in bad weather, and on special missions, specific inspection requirements and precautions must be clarified, and necessary measures must be taken. Special inspections must be attended by leaders on duty. After each patrol inspection, the inspected equipment defects should be recorded in the equipment defect record book, and the patrol inspectors are responsible for the records.
5. Technical file of transformer station
Transformer stations must establish the following technical files.
5.1 The instruction manual of the equipment manufacturer;
5.2 Factory test records of electrical equipment;
5.3 Relevant information on installation handover;
5.4 Improvement of electrical equipment, minor repair construction records and construction reports;
5.5 Overhaul of electrical equipment over the years and regular preventive construction reports;
5.6 Special reports on accidents, obstacles and operation analysis of electrical equipment;
5.7 Serious defects of electrical equipment, equipment changes and modification records.
6. Development of transformer stations
Transformer stations have appeared since the establishment of the first real power system. As an integral part of the power system, transformer stations have developed together with the power system for more than 100 years. Great changes have taken place in voltage levels and equipment conditions.
On the construction site of the transformer station, from the original all open outdoor transformer stations, indoor transformer stations and some underground transformer stations gradually appeared.
In terms of voltage level, with the development of electric power technology, a small number of 110kV and 220kV transformer stations are used as hub transformer stations. The transmission mode of the small grid with 35kV as the terminal transformer station has gradually developed into a large grid transmission mode with UHV 1000kV and 500kV transformer stations as hub transformer stations, and 220kV and 110kV transformer stations as terminal transformer stations.
In terms of electrical equipment, the primary equipment has gradually developed from the original open outdoor equipment to fully enclosed gas combined electrical equipment (GIS) and semi-closed gas integrated electrical equipment (HGIS); the secondary equipment has developed from the early transistor and integrated circuit protection to microcomputer protection.
7. Zero carbon transformer station
On January 18, 2022, the 110 kV Gaoxiang (Qingshu) transformer station built by Jiangsu Wuxi Power Supply Company was officially put into operation, becoming the first 110 kV "zero-carbon" transformer station in China.