what is an electrical substation
**An electrical substation** is a crucial component of the electrical power system. It **regulates voltage levels,
distributes electrical energy, and ensures the efficient transmission of electricity from power plants to end-users
(households, enterprises, and industries)**. By utilizing transformers and other electrical equipment, it serves
as a "power hub".
**Key Functions of an Electrical Substation**
1. **Voltage Transformation**
- **Step up** the voltage (for example, 10 to 30 kilovolts → 110 to 765 kilovolts) for long-distance power
transmission, thereby reducing energy loss.
- **Step down** the voltage (for example, 110 kilovolts → 10 kilovolts → 220 to 480 volts) for safe distribution
to users.
2. **Power Distribution**
- **Divert** the electricity from high-voltage transmission lines to local distribution lines.
3. **Power Grid Stability and Protection**
- Use switches, relays, and **lightning arresters** to deal with faults (such as short circuits) and maintain the
reliability of the power grid.
### **Types of Electrical Substations**
| Type Type | Function | Voltage Range |
| Transmission Substation | Connect the power plant to the high-voltage transmission grid (step up or step down the voltage) | 110 kilovolts to 765 kilovolts |
| Distribution Substation | Step down the high-voltage electricity to a voltage usable by users (such as community substations) | 10 kilovolts to 35 kilovolts → 220 to 480 volts |
**Core Equipment**
- **Transformer**: Changes the voltage through electromagnetic induction (*Key formula*: \( \frac{V_1}{V_2}
= \frac{N_1}{N_2} \)).
- **Circuit Breaker**: Automatically cuts off the circuit in case of a fault.
- **Switchgear**: Controls the on and off of the electricity, making maintenance convenient.
**Examples of Workflow**
1. Power plant (10 kilovolts) → **Step-up Substation** (220 kilovolts) → High-voltage transmission line
2. High-voltage electricity → **Regional Substation** (step down to 10 kilovolts) → Distribution line
3. Distribution line → **Community Substation** (step down to 220 volts) → Household
**Reasons for Its Importance**
- **Energy Efficiency**: High-voltage transmission reduces losses, and low-voltage distribution ensures safety.
- **Reliability**: Ensures continuous power supply and isolates faulty areas.
- **Scalability**: Adapts to different scales of power demands (from urban areas to rural areas).
**Conclusion**: An electrical substation is the "heart" of the power system. Through **voltage regulation**
and **power distribution**, it safely and efficiently transmits the electrical energy from power plants to end-users.
