What equipment is needed for a 110kV transformer substation?

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A 110kV transformer substation requires the coordinated operation of multiple types of equipment to ensure the stable transmission, transformation and distribution of electric power. The following is an introduction to the main equipment: ### Primary Equipment

- **Main Transformer**: It converts the high-voltage electrical energy of 110kV into appropriate low-voltage electrical energy and is the core equipment of the substation. Its capacity is determined according to the load requirements of the power supply area. Common specifications include 31.5 MVA, 40 MVA, 50 MVA, etc.

- **Switchgear**: - **Circuit Breaker**: It can connect and disconnect circuits under normal and fault conditions, has the ability to extinguish arcs, and can quickly cut off the current when faults such as short circuits occur to protect the safety of equipment and lines.

- **Disconnector**: It is mainly used to isolate the power source to ensure the safety of maintenance. It is operated when there is no current in the circuit to create an obvious open point.

- **Load Switch**: It can connect and disconnect the load current under normal conditions, but cannot cut off the short-circuit current. It is usually used in combination with a fuse.

- **Busbar**: It is a conductor for collecting and distributing electrical energy, usually made of copper or aluminum, and is divided into hard busbars and soft busbars. It connects various electrical equipment to enable the transmission of electrical energy within the substation.

- **Instrument Transformers**:

- **Voltage Transformer**: It converts high voltage into low voltage in proportion, which is used for measurement and protection, provides measurement signals for voltmeters, wattmeters, etc., and also provides voltage signals for relay protection devices.

- **Current Transformer**: It converts large current into small current in proportion, which is used for measurement and protection, provides measurement signals for ammeters, watt-hour meters, etc., and also provides current signals for relay protection devices.

- **Surge Arrester**: It is used to protect electrical equipment from damage caused by lightning overvoltage and switching overvoltage. When overvoltage occurs, the surge arrester will automatically conduct and lead the overvoltage into the earth to protect the insulation of the equipment.

- **Fuse**: When the current in the circuit exceeds the specified value, the fuse element will melt and cut off the circuit, playing a role in short-circuit protection. Commonly used ones include high-voltage current-limiting fuses, etc.

- **Power Capacitor**: It is used to compensate reactive power, improve power factor, reduce power loss and improve power quality. It can be switched in groups according to needs.

### Secondary Equipment - **Relay Protection Device**: It can automatically detect faults in the power system, quickly send out signals or cut off faulty equipment to ensure the safety of equipment and personnel. Common ones include line protection, transformer protection, busbar protection, etc.

- **Integrated Automation System**: It realizes real-time monitoring, data acquisition, remote control and protection functions for the equipment in the substation, improving the operation management level and automation degree of the substation.

- **DC Power Supply System**: It provides a stable DC power supply for the secondary equipment in the substation, including battery packs, charging devices, DC busbars, etc., ensuring that the secondary equipment can still work normally when the AC power supply fails.

- **Communication Equipment**: It is used for information transmission between the substation and the dispatching center, centralized control center, etc., including optical fiber communication equipment, carrier communication equipment, wireless communication equipment, etc., realizing remote monitoring and the transmission of dispatching instructions.

### Auxiliary Equipment - **Station Service Transformer**: It provides a low-voltage power supply for lighting, maintenance, control and other equipment in the substation. Usually, a 10kV / 0.4kV transformer is used.

- **Reactive Power Compensation Device**: Besides power capacitors, there are also Static Var Compensator (SVC), Static Var Generator (SVG), etc., which can automatically adjust the reactive power output according to the reactive power requirements of the system to stabilize the voltage.

- **Grounding Device**: It is composed of grounding electrodes and grounding wires, providing a channel for the fault current to flow into the earth, ensuring the safety of equipment and personnel, reducing the grounding resistance and ensuring the reliability of grounding.

- **Fire-fighting Equipment**: It includes fire extinguishers, fire hydrants, fire alarm systems, etc., which are used to prevent and extinguish possible fires in the substation and ensure the safety of equipment and facilities.

- **Ventilation and Cooling Equipment**: For example, ventilation fans and air conditioners in the transformer room are used to reduce the heat generated during the operation of the equipment and ensure that the equipment operates within the normal temperature range.