1.发电机失磁保护
1. Generator loss of excitation protection
东莞发电机维修告诉你失磁保护作为发电机励磁电流异常下降或完全消失的失磁故障保护。由整定值自动随有功功率变化的励磁低电压Ufd(P)、系统低电压、静稳阻抗、TV断线等判据构成，分别动作于发信号和解列灭磁。
Dongguan generator maintenance tells you that the loss of excitation protection serves as a loss of excitation fault protection for generators with abnormal decrease or complete disappearance of excitation current. Composed of criteria such as excitation low voltage Ufd (P), system low voltage, static impedance, TV disconnection, etc., which automatically vary with the active power according to the set value, they respectively act on signal generation and train de excitation.
2.发电机过激磁保护
2. Generator overexcitation protection
过激磁保护是反应发电机因频率降低或者电压过高引起铁芯工作磁密过高的保护。
Overexcitation protection is a protection that reflects the high magnetic density of the iron core of a generator caused by a decrease in frequency or high voltage.
3.发电机定子接地保护
3. Generator stator grounding protection
发电机定子接地保护作为发电机定子单相接地故障保护，由基波零序电压部分和三次谐波电压两部分组成，基波零序电压保护机端至机尾95%区域的定子绕组单相接地故障。
The generator stator grounding protection, as a single-phase grounding fault protection for the generator stator, consists of two parts: the fundamental zero sequence voltage part and the third harmonic voltage part. The fundamental zero sequence voltage protection protects the single-phase grounding fault of the stator winding in the 95% area from the machine end to the tail of the machine.
4.发电机定子匝间保护
4. Generator stator interturn protection
保护由纵向零序电压和故障分呈负序方向判据构成,设置PT断线闭锁措施，作为发电机内部匝间、相间短路以及定子绕组开焊的主保护。
The protection is composed of longitudinal zero sequence voltage and negative sequence fault direction criterion, with PT disconnection blocking measures set as the main protection for internal inter turn and inter phase short circuits of the generator and stator winding open welding.

5.失步保护
5. Out of step protection
保护采用三阻抗元件，发动机通过阻抗的轨迹变化来检测滑极次数并确定振荡中心的位置。
The protection adopts a three impedance element, and the engine detects the number of sliding poles and determines the position of the oscillation center through the trajectory change of impedance.
6.低频累加保护
6. Low frequency accumulation protection
低频累加保护反应系统频率降低对汽轮机影响的累积效应，保护由灵敏的频率继电器和计数器组成，经出口断路器辅助接点闭锁(即发电机退出运行时低频累加保护也退出运行)，累计系统频率低于频率定值47.5Hz的时间，当累计时间达到整定值3000秒时，经延时30秒动作于发信号。
The low-frequency accumulation protection reflects the cumulative effect of a decrease in system frequency on the steam turbine. The protection consists of sensitive frequency relays and counters, which are locked by the auxiliary contact of the outlet circuit breaker (i.e. the low-frequency accumulation protection also exits operation when the generator exits). The accumulated system frequency is below the frequency setting value of 47.5Hz, and when the accumulated time reaches the set value of 3000 seconds, it acts as a signal after a delay of 30 seconds.
7.励磁回路过负荷保护
7. Excitation circuit overload protection
励磁回路过负荷保护用作转子励磁回路过流或过负荷的保护，接成三相式，由定时限和反时限两部分组成。
The excitation circuit overload protection is used as a protection for overcurrent or overload in the rotor excitation circuit, connected to a three-phase type, consisting of a fixed time limit and an inverse time limit.
8.发电机转子一点接地保护
8. Generator rotor one-point grounding protection
发电机转子一点接地保护用于反应发电机转子回路一点接地故障，保护采用乒乓式切换原理，轮流采样转子回路正、负极对地电压，通过求解两个不同的接地回路方程，实时计算转子接地电阻和接地位置。
The one-point grounding protection of the generator rotor is used to reflect a one-point grounding fault in the generator rotor circuit. The protection adopts the ping-pong switching principle and takes turns sampling the positive and negative voltage of the rotor circuit to ground. By solving two different grounding circuit equations, the rotor grounding resistance and grounding position are calculated in real-time.
9.发电机对称过负荷保护
9. Generator symmetrical overload protection
保护装置由定时限和反时限两部分组成，定时限部分经时限5秒动作于信号。
The protection device consists of a fixed time limit and an inverse time limit, with the fixed time limit acting on the signal after a time limit of 5 seconds.
10.发电机负序过负荷保护
10. Generator negative sequence overload protection
保护装置由定时限和反时限两部分组成，定时限动作电流按躲过二手发电机组长期允许的负序电流值和躲过大负荷下负序电流滤过器不平衡的电流值整定，经时限3秒动作于信号。
The protection device consists of two parts: a fixed time limit and an inverse time limit. The fixed time limit action current is set according to the long-term allowable negative sequence current value of the second-hand generator set and the current value of the negative sequence current filter under maximum load, and acts on the signal after a time limit of 3 seconds.
11.发电机过电压保护
11. Generator overvoltage protection
在发电机并网前，如机端电压达到1.3倍额定值时，发电机过电压经延时0.5秒动作于解列灭磁。
Before the generator is connected to the grid, if the terminal voltage reaches 1.3 times the rated value, the generator overvoltage will be triggered by a 0.5 second delay to disconnect and de-excitation.
12.发电机纵差保护
12. Generator longitudinal differential protection
按由差动元件两侧输入电流的不同进行分类，可以分成完全纵差保护和不完全保护两类。
According to the different input currents on both sides of the differential element, it can be classified into two categories: complete longitudinal differential protection and incomplete protection.