发电机中性点接地电阻柜工作原理概
Working principle of generator neutral grounding resistance cabinet
发电机在运行中，发生单相接地是最常见的故障，其故障点出现电弧接地时会进一步扩大定子绕组绝缘损害甚至铁芯灼伤烧结，如不及时发现并快速切除故障，将发展成为相间或匝间短路。基于上述原因，国际广泛采用发电机中性点高阻接地，以限制接地电流，防止各种过电压的危害。中性点通过电阻器接地可以把故障电流限制到适当值，提高继电保护的灵敏度作用于跳闸；同时又使故障点仅可能发生局部轻微灼伤，把暂态过电压限制到正常线电压对中性点电压的2.6倍，限制电弧的重燃；防止弧光间隙过电压损坏主设备；同时可有效防止铁磁谐振过电压，从而保证发电机的安全运行。
In the operation of generator, single-phase grounding is the most common fault. When arc grounding occurs at the fault point, it will further expand the insulation damage of stator winding and even iron core burning and sintering. If the fault is not found and quickly removed, it will develop into phase to phase or turn to turn short circuit. Based on the above reasons, high resistance grounding of generator neutral point is widely used in the world to limit the grounding current and prevent the harm of various overvoltage. The neutral point grounding through resistor can limit the fault current to an appropriate value, improve the sensitivity of relay protection and act on tripping; at the same time, it can only cause local slight burn at the fault point, limit the transient overvoltage to 2.6 times of the normal line voltage to the neutral point voltage, limit the arc re ignition, prevent the arc gap overvoltage from damaging the main equipment, and effectively prevent ferromagnetic resonance Vibration overvoltage, so as to ensure the safe operation of the generator.