| 引用本文: | 张琦雪,冯桂青,陈 俊,严 伟,沈全荣.汽轮发电机定子绕组缺线圈运行时的负序过负荷保护分析[J].电力自动化设备,2014,34(1): |
| ZHANG Qixue,FENG Guiqing,CHEN Jun,YAN Wei,SHEN Quanrong.Analysis of negative-sequence overload relay protection for turbine generator operating with asymmetrical stator windings[J].Electric Power Automation Equipment,2014,34(1): |
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| 摘要: |
| 一台缺线圈运行的汽轮发电机，实测有不超过6.2 p.u. 的负序电流。为防止负序过电流损伤转子铁芯，需要定量评估电枢电流的影响。假设在故障相上增加一个“叠加绕组”，采用叠加原理，分析并计算出电枢反应的反转基波磁动势与正序、负序电流之间的定量关系，进一步计算得到等效的负序电流。分析表明因绕组不对称，负序电流和正序电流都会产生反转的基波磁动势。对于这台发电机的负序过负荷保护，可适当降低长期允许负序电流值I2∞至8.5 p.u.，不必降低承受负序电流能力的常数I 2 2 t。 |
| 关键词: 汽轮发电机 定子 负序过电流 过负荷保护 继电保护 定子绕组 叠加原理 |
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| Analysis of negative-sequence overload relay protection for turbine generator operating with asymmetrical stator windings |
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ZHANG Qixue1, FENG Guiqing2, CHEN Jun1, YAN Wei1, SHEN Quanrong1
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1.NARI-Relays Electric Co.，Ltd.，Nanjing 211102，China;2.Shenzhen Energy Group Co.，Ltd.，Shenzhen 518031，China
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| Abstract: |
| A turbine generator temporarily operating with asymmetrical stator windings has measured negative-sequence current less than 6.2 %. The effect of asymmetrical armature currents should be quantitatively evaluated to avoid the rotor damage caused by the negative-sequence overcurrent. A hypothetical superposing winding is added to the faulty phase and the superposition principle is used to analyze the quantitative relation between the contra-rotational fundamental MMF（Magnetic Motive Force） and the positive／negative sequence current. The equivalent negative-sequence current is then calculated. Analysis shows that，both negative and positive sequence currents contain MMF due to the asymmetrical stator windings. It is suggested that the I2∞ of the negative sequence overload relay protection for this generator be reduced to 8.5 p.u. while its I22t kept. |
| Key words: steam turbine generator stators negative-sequence overcurrent overload relay protection relay protection superposition principle |
