The Power Supply Radius of Transformers

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1. **Definition**
- The power supply radius of a transformer refers to the distance from the output terminal of the transformer to the farthest end it supplies power to. It is an important indicator for measuring the power supply range of the transformer. The size of the power supply radius directly affects many aspects such as power supply quality and line losses.
2. **Influencing Factors**
- **Voltage Level**
- Transformers with different voltage levels have different reasonable power supply radii. For example, for a 10kV line, the general power supply radius is about 5 - 15 kilometers. This is because the higher the voltage level, the stronger the transmission capacity of the line, and the relatively smaller voltage drop caused by the line resistance and reactance that can be tolerated, so it can supply loads at a greater distance. For a 0.4kV (low - voltage) line, the power supply radius is usually within 0.5 kilometers. The main reason is that the voltage of the low - voltage line is relatively low. If the power supply radius is too long, the line losses will be too large, resulting in a too low voltage at the end, which cannot meet the normal operation requirements of electrical equipment.
- **Line Material and Cross - Section**
- The material (such as copper, aluminum) and cross - sectional area of the line have a significant impact on the power supply radius. The conductivity of copper wires is better than that of aluminum wires. Under the same current load and allowable voltage drop conditions, the power supply radius of copper wires can be larger than that of aluminum wires. If the cross - sectional area of the wire is increased, its resistance will decrease. According to Ohm's law \(U = IR\) (\(U\) is the voltage drop, \(I\) is the current, \(R\) is the resistance), under the same current condition, the voltage drop will decrease, thus the power supply radius can be appropriately increased. For example, for a certain 10kV line, if a 70 - square - millimeter aluminum wire was originally used, the power supply radius might be 8 kilometers. When it is replaced with a 120 - square - millimeter aluminum wire, the power supply radius might increase to about 10 kilometers.
- **Load Size and Power Factor**
- The size of the load determines the magnitude of the current in the line. According to \(P = UI\cos\varphi\) (\(P\) is power, \(U\) is voltage, \(I\) is current, \(\cos\varphi\) is the power factor), when the power \(P\) increases, if the voltage \(U\) remains unchanged, the current \(I\) will increase. A larger current will generate a greater voltage drop on the line. Moreover, the power factor \(\cos\varphi\) is also crucial. A low power factor means a large reactive power, and the line current will increase further, thus limiting the power supply radius. For example, in an area with concentrated industrial loads, if the power factor is 0.8, the power supply radius of the same transformer and line may be about 20% - 30% smaller than that when the power factor is 0.9.
3. **Calculation Methods**
- **Simple Estimation (for Three - Phase Balanced Loads)**
- According to the voltage drop formula \(\Delta U=\frac{PL}{CS}\) (\(\Delta U\) is the voltage drop, \(P\) is the three - phase power in kilowatts; \(L\) is the line length in kilometers; \(C\) is a coefficient, \(C = 46.3\) for aluminum wires and \(C = 77.5\) for copper wires; \(S\) is the cross - sectional area of the wire in square millimeters). Generally, it is required that the voltage drop \(\Delta U\) does not exceed a certain proportion of the rated voltage (for example, for a 10kV line, \(\Delta U\) does not exceed 5% - 7% of the rated voltage). The power supply radius \(L\) can be deduced from this formula.
- **Accurate Calculation (Considering Factors Such as Line Reactance)**
- It is necessary to use complex power system power flow calculation methods. Taking a certain 10kV power supply system as an example, the resistance \(R\) and reactance \(X\) of the line, and the power of the load \(P + jQ\) (\(P\) is the active power, \(Q\) is the reactive power) need to be considered. According to the formula \(\Delta U=\frac{PR + QX}{U}\) (\(U\) is the rated voltage of the line), the maximum power supply radius that meets the voltage quality requirements can be obtained through iterative calculation and other methods. This method is more commonly used in the planning of large and complex power supply networks.
4. **Importance**
- **In Terms of Power Supply Quality**
- If the power supply radius is too long, it will lead to a too low voltage at the end. For example, in the rural power grid, in some remote areas, due to the too large power supply radius, during the peak power consumption period, the voltage of the end users may be lower than 80% of the rated voltage. This will make the lighting fixtures dim, and equipment such as motors cannot be started normally or operate with low efficiency. Reasonably controlling the power supply radius can ensure that the voltage at the user end is within the qualified range and improve the power supply quality.
- **In Terms of Line Losses**
- The line losses are directly proportional to the line length. When the power supply radius is too large, the line losses will increase significantly. Taking a 10kV overhead line as an example, if the power supply radius is increased by 1 kilometer, under a certain load condition, the line losses may increase by about 10% - 15%. Reducing the power supply radius helps to reduce line losses and improve energy utilization efficiency. #tiktokrefugee#cat#tiktokban#china#抖音难民#transformers #transformer #electrical #technology #factory #foryou #viral #shortvideo #manufacture #machine #power #shorts #trending #wiring #factorywork #electricalengineering #powertransformer #electriacaltransformer #manufacturing #process #manufacturer #manufacturingprocess #HighVoltageWinding #usa #canada #australia #uk#dailyvlog #daily #bluecollar #Tesla#WorkshopDaily #electricwire #powerengineering #transformer #foilwinding #lowvoltagenation #electricalengineering #LowVoltageFoilWinding #FoilWinding #ElectricalEngineering #TransformerDesign #InductorDesign#TransformerTechnology #ElectricalEngineering #FoilWinding #TransformerManufacturing #EnergyEfficiency #ElectricalDesign #TransformerWinding #EngineeringInnovation #TransformerTechnology #CopperFoilWinding #PowerTransformers #EngineeringTechniques #ElectricalComponents