After the Second Industrial Revolution, humanity entered the “Age of Electricity.” The discovery of electricity brought tremendous convenience to daily lives—modern electronic products such as phones, computers, air conditioners, and washing machines gradually became essential. But do you ever wonder where and how electricity originates when you use it?

In fact, from the moment electricity is generated, it begins its marathon journey. With the power plugs and sockets of end users as the destination, it goes through various stages: generation, transmission, distribution, and consumption. Voltage changes continuously during this journey. The complexity of these changes is mainly due to electrical losses during transmission, especially in long-distance power transmission. Therefore, for long-distance transmission, large power transformers are used to increase voltage, reduce current, and decrease wire heating, effectively reducing energy losses in the transmission lines.

If we use the two formulas below, the conclusion would be more persuasive:

PL= ² ⋅ R

I=P/U

*Note:

• “PL” is the power loss (W)

• “I” is the electric current (A)

• “R” is the resistance (Ω)

• “P” is electrical power (W)

• “U” is the voltage (V)

These two formulas emphasize the relationship between current, resistance, and power consumption. During the process of electrical transmission, higher voltage results in lower current and less energy loss.

Therefore, the importance of transformers cannot be ignored. In a modern power grid system, various transformers serve distinct roles at different stages. So, let's see how electricity is generated, transmitted, distributed, and consumed!

Stage of Generation

Until today, we have learned about various electricity generation technologies. For example, we can use non-renewable energy sources such as coal, fossil fuels, and nuclear power. We also discovered renewable energy sources like wind, solar, and hydropower.

In summary, thermal power plants generate electricity by burning coal, oil, or natural gas to produce heat energy, which creates high-pressure steam to drive power generators. Wind and hydropower harness mechanical energy from wind or water to produce electrical energy. Solar cells convert solar energy directly into electricity through the photovoltaic effect.

Through various methods, electricity is generated. But how does it reach different destinations? During the generation stage, step-up substations play a crucial role. As one of the most essential components of power plants, step-up substations increase the electrical voltage for transmission over long distances. The voltage output from these substations varies based on the transmission distance and the size of the city, typically around 220 kV.

Stage of Transmission

At this stage, electricity transmission cannot be separated from substations and transformers. Here is the starting point of the power transition—after passing through an ultra-high-voltage substation, the voltage can even reach 1000 kV.

During the transmission process, electricity passes through a series of transmission towers. The longer the transmission distance, the taller these towers are constructed. Eventually, the electricity reaches step-down transmission substations at switching points in an electrical grid. The voltage will be gradually reduced by these substations until it matches the demand voltage. Typically, high-voltage ranges in megacities are around 500 kV, and that needs 500 kV ultra-high-voltage substations to “work hard.”

Stage of Distribution

After passing through several substations during the transmission stage, the voltage in the city is reduced to around 110 kV. From there, electricity enters the electric power distribution network, where 110 kV substations can further decrease the voltage to 10 kV.

The 10 kV power grid cables are normally buried underground. The electricity travels through electrical conduits and reaches the ring main units (RMUs). RMUs are used in power distribution systems and are usually installed between distribution transformers and distribution panels. They serve to switch, distribute, and protect the power system, primarily controlling and distributing current.

Now, 10 kV electricity is getting closer to our daily lives. After being allocated by RMUs, the power is transformed by distribution transformers into lower voltages, such as 220 V or 380 V, which enter different areas of the city. Various installation methods exist for these transformers, including pad-mounted substations, pole-mounted transformers, or electrical rooms.

The next stop is the low-voltage cable branch box. Electricity is distributed to various public distribution boxes, then electric meter boxes in different buildings and indoor distribution boxes for end-users. Finally, the journey of power distribution concludes.

Stage of Consumption

When you turn on the main switch of the distribution box in your home, all the sockets become active. At this stage of electric consumption, common household appliances can be plugged in and used.

This is the end of electricity’s marathon journey, but please remember to save energy!

Through this complex "marathon journey," electricity enters homes from distant power plants, using numerous substations and transformers. Ultra-high-voltage substations, step-up substations, high-voltage substations, medium-voltage substations, and low-voltage substations are perfect stations for power transmission. Therefore, the necessity of substations and transformers in this journey cannot be ignored.

With over 30 years of experience, CEEG has become a well-established manufacturer of transformer equipment. Our product range includes various dry-type transformers, oil-immersed transformers, a variety of substations, and switchgear. Today, our products are exported to over 80 countries and regions, spanning Asia, Africa, Europe, and South America. Whatever your needs, we are happy to serve you!