Generally, when the generator excitation system is in the overexcited state, both the active power and the reactive power are transmitted to the system, and the power factor is positive. This operating state is called the late phase operation, also called the stagnation phase operation.
Usually, the generator sends both active power and reactive power to the system, and the power factor is positive. This operating state is called late phase operation.
Phase in operationReduce the generator excitation current, reduce the generator potential, the power factor angle becomes advanced, the generator load current generates the magnetically assisted armature reaction, the generator delivers the active power to the system, but absorbs the reactive power, this operation Phase-in operation
When the generator is in normal operation, it provides active power to the system and also provides reactive power. The stator current lags behind the terminal voltage by an angle. This state is the late phase operation. When the excitation current is gradually reduced, the generator is changed from providing reactive power to the system to absorbing reactive power from the system, and the stator current changes from hysteresis to an angle of the leading generator terminal voltage. This state is the phase-in operation.
When the synchronous generator enters phase, the excitation current is greatly reduced in the later phase operation state, and the generator potential Eq is also reduced accordingly. From the P-power angle relationship, in the case of constant work, the power angle must increase correspondingly, the ratio of the whole step work is also reduced, and the static stability of the generator is reduced. Its stability limit is related to the generator short circuit ratio, external reactance, automatic excitation regulator performance and whether it is put into operation.
Phase modulation operationPhase-modulated operation means that the generator does not emit active power and is only used to transmit the operating state of the inductive reactive power to the grid, thereby regulating the system's reactive power and maintaining the system voltage level.
When the generator is in phase modulation operation, it can be operated either overexcitation or underexcitation. During overexcitation operation, the generator emits inductive reactive power; when underexcited, the generator emits capacitive reactive power. Generally, when the phase modulation operation is performed, the generator operates in an overexcited state that emits inductive reactive power.
The phase-in operation of the generator: During the operation of the power system, if the reactive power is excessive, the voltage of the system will rise, affecting the normal operation of the system. At this time, the generator needs to be adjusted to the phase-in operation state, and the active power is generated. Absorb reactive power. It plays a role in reducing the system voltage. It is in a stable operating state, but the generator will also have a bad influence when it enters the phase.
The difference and connection between generator phase, phase and phase modulationFirst, several grid-connected operating states of synchronous generators:
1. Delayed phase operation (normal operation)----The generator sends active power and reactive power (capacitive) to the grid at the same time.
2. Incoming phase operation (advance operation)----The generator sends the active power to the grid to absorb the reactive power of the grid.
3. Phase-modulated operation----The generator's active power absorbed by the grid maintains synchronous operation and sends reactive power (capacitive) to the grid.
4. Motor running (non-normal operation)-----The generator simultaneously absorbs the active power and reactive power of the grid to maintain synchronous operation.
The first three operating states are the normal operating states of the synchronous generator, and the second and fourth operating states should be avoided. In the second state (phase-in operation), the generator is prone to out-of-step oscillation, and the fourth operating state is wasted and meaningless.
Second, the complexity is simple:
It is the phase relationship between voltage and current. The voltage lead current is called the phase, the voltage lag current is called the phase, and the phase modulation is an operating state (synchronous motor state). At this time, the generator does not emit active power and only emits reactive power. The reactive power complements.
Third, the professional term describes my life status
The motor can run steady in the first, second, third and fourth quadrants, the first quadrant: the generator state, at which time the generator sends active and reactive power to the grid; the second quadrant: phase-modulated operating state, at which time the motor is from the grid Absorbing active power and emitting reactive power; Third quadrant: Motor state, at this time, the motor absorbs active and reactive power from the grid to maintain its own operation; Fourth quadrant: Incoming phase operation state, at this time, the generator emits active power and absorbs from the grid without Gong. Briefly stated:
First quadrant: active X: positive; reactive Y: positive;
Second quadrant: active X: negative; reactive Y: positive;
Third quadrant: active X: negative; reactive Y: negative;
Fourth quadrant: active X: positive; reactive Y: negative;
If you compare the state of my life with the running state of the motor, there are the following: The meritorious deputy represents that I have a job, that is, usually stupid, and the "business" that people with illusions often call it, this thing is real, It can promote the rotation of the motor, which is the driving force for real social development, and the mate selection standard of people who are more and more realistic.
Responsibility means that I have a love, love is nothing but ethereal things, often can not bring anything practical, often leave a pain, just like reactive power on the grid, do not do business, limit the output of the generator, while still Increase network loss, but can you not? No, because the grid still has so many emotional loads, the generators should also talk about love during the holiday season. Then, a more complete explanation of my life state can be made:
Live in a quadrant: At this time I have a job and love;
Live in the second quadrant: at this time I only have love and no work;
Live in the three quadrants: at this time I have no job and no love;
Live in four quadrants: At this point I have a job without love.
The motor runs in the normal operation state of the first and third quadrants, but when the synchronous motor runs in the second and fourth quadrants, it is not normal. The fourth quadrant operating state (phase-in operation) reduces the excitation current and can be operated for a long time. . That is to say, if a person has a job without love, he can survive for a long time without much effort, but when running in the second quadrant, it is necessary to increase the excitation current. At this time, this person has to work hard to maintain this work without love. stage.
Now I live in the three quadrants. When I have a job, I jump into the four imaginations, or when I have love, I jump into the second quadrant. When I have both work and love, I jump into the quadrant. That may be my end. No matter how I jump into the first quadrant from now on, one or two of the second and fourth quadrants are my must, because I can't get love when I get a job or get a job when I just get love. .
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