变压器计算器
计算变压器满载电流和阻抗。
尝试一个工程 5
每项工作都会预填示例数值。请替换为您自己的数值。
- Check a transformer secondaryThe secondary current and the fault level of a 1000 kVA unit.
- Find the currents of a 500 kVA transformerThe primary and secondary currents of a 500 kVA unit.
- Find fault level of a 300 kVA unitThe secondary fault current at 4 % impedance.
- Check an isolating transformerThe currents of a 5 kVA single‑phase unit.
- Check a 22 kV transformerThe primary current of a 1500 kVA, 22 kV unit.
输入
使用默认输入值的示例计算。
- 额定值
- 500 kVA
- 相
- 三相
- 一次侧电压
- 11,000 V
- 二次侧电压
- 400 V
- 阻抗
- 6 %
二次满载电流
721.69A
- 一次侧满载电流
- 26.24A
- 二次故障电流
- 12,028.13A
此结果仅供设计参考。请对照现行标准进行核验。
计算步骤
- 一次侧满载电流26.24A
- 二次侧满载电流结果721.69A
- 二次侧故障电流12,028.13A
关于此计算器
How this is calculated
The tool gives the full load currents of a transformer and its secondary fault current. It uses the rating and the impedance from the nameplate.
- Inputs. You enter the rating in kVA and the number of phases. You also enter both voltages and the impedance in percent.
- Primary full load current. On three phases, I = kVA × 1000 ÷ (√3 × primary voltage). On one phase, it divides by the voltage alone.
- Secondary full load current. The tool applies the same formula at the secondary voltage.
- Secondary fault current. It divides the secondary full load current by the impedance as a fraction. For 6 %, that means dividing by 0.06.
The tool reads no table. You enter the voltages and the impedance.
Worked example
- 500 kVA, 11 kV to 400 V, 6 % impedance, three phase. The primary full load current is 26.24 A. The secondary full load current is 721.69 A. The secondary fault current is 12,028.13 A.
Limits
The fault current assumes an infinite upstream source. A real source has impedance, so the true fault current is lower. Use the fault level calculator to include the source. The tool does not model the cable after the transformer. It does not size the protection. Impedance is a nameplate value with a tolerance.
Use the primary current to check the supply side device. Use the secondary current to check the main switch and the busbar. Take the impedance from the nameplate, because it has a tolerance.
See also: Transformer full load current, 1000 kVA at 11 kV, Transformer secondary fault current, 500 kVA and Prospective fault current at a board.
问题
结果仅供设计参考。请依据现行标准核对。
变压器计算器有什么作用？
工具报告一次侧满载电流、二次侧满载电流及二次侧故障电流。它以千伏安额定值、一次侧和二次侧电压、阻抗百分比及相数为输入。
哪些输入最重要？
额定容量和两个电压决定两侧的满载电流。阻抗百分比决定二次侧故障电流：阻抗越低，故障电流越大。相数对两侧电流均施加根号三的系数。
常见的注意事项有哪些？
故障电流假定上游电源为无限大，因此是最不利情况，工具在每项结果中均注明此点。电缆和网络阻抗未计入。阻抗百分比上限为 30。输入值保存在页面地址中，因此链接可重现该结果。
计算示例
背景
- Short-circuit withstand and the k factorThe adiabatic check in plain terms: prospective fault current, clearing time and k, worked on 25 mm² copper XLPE at 10 kA for 0.1 s.
- Arc flash basicsArcing current, incident energy, boundary and working distance explained, with three engine runs that show clearing time beating fault current every time.
相关工具
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有问题，或数值看起来有误？联系我们。