Generator Manufacturer Tells The Hazard Of Phase Operation

Diesel generator set: by the engine, generator and control system composition, so called generator set. Diesel generator set is a kind of power equipment which takes diesel engine as prime mover and drives synchronous generator to generate electricity. It is a power generation device with quick start, convenient operation and maintenance, less investment and strong environmental adaptability.

When the generator runs normally, it provides active and reactive power to the system, and the stator current lags behind the terminal voltage by an Angle. This state is called post-operation. When the excitation current decreases gradually, the generator changes from providing reactive power to absorbing reactive power from the system, and the stator current changes from lagging to leading generator terminal voltage by an Angle. This state is called leading phase operation. When the synchronous generator runs in advance, the excitation current decreases greatly, and the generator potential Eq decreases accordingly. From the p-power Angle relation, when the active power is constant, the power Angle will increase correspondingly, the whole step power ratio will decrease correspondingly, and the static stability of the generator will decrease. Its stability limit is related to short circuit ratio of generator, external reactance, performance of automatic excitation regulator and whether it is put into operation.

Compared with the later operation, the flux leakage at the stator end of the generator increases in the advanced operation. Especially large generator line load is high, the end magnetic leakage is large in normal operation, the end core pressure refers to the temperature of the connector increases, in advance phase operation magnetic leakage increases, temperature rise is intensified. During the lead phase operation, the terminal voltage of the generator decreases, and the auxiliary voltage decreases accordingly. If it exceeds 10%, it will affect the operation of the auxiliary power.

Therefore, the operating depth of synchronous generator should be determined by experiment. That is, how much reactive power can be absorbed to maintain the static and transient stability of the system, and the temperature rise of each component does not exceed the limit to meet the voltage requirements.

Hazards caused by phase operation by generator manufacturer:

1. Increasing the active load of the generator will make the generator unstable, which will easily lead to the unstable operation of the generator and even the occurrence of system oscillation accidents.

2. Continue to reduce the excitation current of the generator and increase the advanced phase depth of the generator, which may lead to the loss of excitation protection action of the generator or the unstable operation of the generator.

3. When the generator runs in advance, the stator current increases and the stator heat increases; When the generator is running in advance phase, the flux leakage rate of the stator end increases, making the end heat the most serious, and the temperature of the stator coil of the generator will continue to rise.

4. When the generator is running ahead of phase, the generator outlet voltage is reduced, so that the 6KV bus voltage is reduced. The high voltage voltage with undervoltage protection will trip; For all operating electrical equipment, the bus voltage decreases and the current increases, causing the equipment to heat up. Long-term operation may damage the insulation of the device.