How to identify LV and HV side of transformer?
Time：2024-12-10 Auther：ZTelec-www.ztelectransformer.com
In the power system, transformer is the core equipment of power conversion and transmission. The distinction between the high voltage side and the low voltage side is very important for the installation, operation and maintenance of the equipment. However, for non-specialists, it can be a challenge to accurately distinguish between the high voltage side and the low voltage side of a transformer.
The basic structure and function of transformer
Before discussing how to distinguish between the high voltage side and the low voltage side of a transformer, we first need to understand the basic structure and function of the transformer. The transformer is mainly composed of iron core, winding, fuel tank, cooling device, etc. Its main function is to change the size of the AC voltage through the principle of electromagnetic induction to meet the needs of different voltage levels of equipment or systems.
How to identify LV and HV side of transformer?
1. Appearance differentiation method
In the appearance of the transformer, the high-voltage side is usually larger than the diameter of the low-voltage side coil, and the number of windings on the high-voltage side is usually less than that on the low-voltage side. This is because the voltage on the high-voltage side is usually higher than that on the low-voltage side, which requires stronger electrical insulation performance. In addition, the wiring on the high voltage side of the transformer is usually set on the top of the transformer body, and the wiring on the low voltage side is on the side or bottom of the fuselage.
2. Identification method
There are some signs on the transformer to help distinguish the high voltage side from the low voltage side. In general, the high voltage side of the transformer is usually marked with “HV”, “H”, “high voltage” and other words. And the low voltage side is marked with “LV”, “L”, “low voltage” and other words.
3. Connection differentiation method
There are also some differences between the high voltage side and the low voltage side of the transformer in the wiring mode. The high-voltage side is the commonly used three-phase AC, usually using “Y”, “Δ” shape connection. And the low-voltage side generally uses single-phase AC, using “single-phase” connection.
4. Open circuit voltage differentiation method
When the transformer is not connected to the load, the open circuit voltage on both sides of the transformer can be measured to determine which side is the high voltage side and which side is the low voltage side. Because the voltage level of the high voltage side is higher, the open circuit voltage will be higher accordingly. The open circuit voltage on the low voltage side is relatively low. By comparing the open circuit voltage on both sides, the high voltage side and the low voltage side can be accurately judged.
Judging the high voltage side and low voltage side of the transformer need to pay attention to the following points:
1. Keep a safe distance and do not touch live parts;
2. To understand the live part, do not touch the equipment at will to avoid the danger of electric shock;
3. Power off before using electrical tools;
4. During line repair and maintenance work, the state of the electrical equipment should be determined. Before repairing the equipment or turning on the power supply of the equipment, wear insulation gloves, insulation vibration hammer and other protective tools.
