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| 摘要: |
| 通过介绍高阻型电压差动保护的原理和主要特点,重点分析了某变电站3号主变高阻抗差动保护误动的原因.分析表明,由于保护装置公共绕组流变与500 kV和220 kV流变特性相差较大,在近端大电流故障电流下将产生差流.从而导致高阻抗差动保护误动.提出通过调整RADHA差动回路可变电阻的串并联阻值.提高高阻抗差动保护整定值的方案.从而解决了外部故障时RADHA因较大穿越电流而产生的不平衡电流及电压造成的误动.调整后保护校验正确,目前运行效果良好. |
| 关键词: 高阻抗差动 励磁阻抗 电流互感器 穿越性故障 |
| DOI： |
| 分类号:TM77 |
| 基金项目: |
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| Misoperation of high impedance differential protection for main transformer |
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YUAN Cheng TAI Nengling
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| Abstract: |
| The misoperation of the high impedance differential protection for main transformer No.3 in a substation is analyzed based on its principle and main features. Research result shows that,under the nearby large current fault,the differential current induced by the big difference of U - I characteristics between the current transformer of common winding and that of 500 kV or 220 kV presents big value,which will cause the protection misoperation. The countermeasure is to increase the protective settings by adjusting the variable resistors in RADHA differential circuit,which avoids the misoperation caused by the unbalanced currents and voltages generated in RADHA by the through currents during external fault. Field operation shows its effectiveness. |
| Key words: high impedance differential protection,excitation impedance,current transformer,through type fault |
