Outdoor Switchyard (Substation)
The place where the switchgear of booster station receives and distributes the electric energy generated from a hydro-generator set, and the high-voltage power distribution device supplies power to the grid or load point after boosting. It is composed of transformer, switchgear, isolating switch, mutual inductor, lightning arrester, busbar device and related building structure. It is transmitted over a long distance through the switchyard.
It can be divided into two categories: outdoor and indoor power distribution devices according to the installation location of electrical equipment. 110kV and 220kV electrical equipment are arranged in the plant when is combined with the characteristics of the layout of the hydropower station, and the various spacing distances are smaller than the outdoor layout, so the area is also small. The civil construction cost is higher than the outdoor layout, and the construction time is longer, but it is not affected by the bad weather. Sometimes in order to reduce construction costs, part of the equipment is still placed outside the plant.
The brief introduction to the structure of the boost switch station:
1. High-voltage Circuit Breaker: It can cut off and connect the no-load and load currents of the line and various electrical equipment when the system is operating normally; In order to prevent expanding the scope of the accident, It can cooperate with the relay guarantee to quickly cut off the fault current when the system is failed;
2. High-voltage Isolation Switch: In order to ensure the safety of high-voltage electrical appliances and devices play a role in isolation between circuits during maintenance work, the isolating switch can only open and close the no-load circuit, and does not have the arc extinguishing function;
3. Current Transformer: Converts high current into low current proportionally. The primary side of the current transformer is connected to the primary system, and the secondary side is connected to measuring instruments, relay protection, etc;
4. Voltage Transformer: For the purpose of protection, metering, and instrumentation, it is converted high voltage into a standard secondary voltage of 100V or lower according to a proportional relationship;
5. Lightning Arrester: That is used to protect various electrical equipment in the power system from damage caused by lightning overvoltage, operating overvoltage, and power frequency transient overvoltage. The arrester is usually connected between the live wire and the ground, which is connected in parallel with the protected equipment.