Phase modulation operation phenomenon of generator

Author：gdlhwt Time：2014-08-22  

Synchronous generator can be operated as a generator, but also can be operated as a motor. When the operation of the generators of crisis protector misoperation or speed control system failure results in main steam valve is closed, the generator to lose the original power, if the generator transverse linkage protection or reverse power protection no action, the generator is running into the condenser.

1 generators into the condenser operation phenomenon:

1) "the main stop valve closed" light plate signal alarm.

2) the generator active power meter indication is negative, electric energy meter inversion. The main valve of steam generator is closed, the generator from the system to draw a small amount of active power to maintain its synchronous operation, compared with the original, the generator active power absorbed by sent into active power, the active power meter indication is negative, electric energy meter inversion.

3) generator reactive power meter indication increases. The generator main steam valve is closed, the output active power suddenly disappear, only from the system to draw a small amount of active power to maintain the no-load rotation, and the excitation current of the generator is not changed. By the generator voltage phasor diagram or generator power output of P - Q characteristic curves, the power angle of D is reduced, the power factor angle increased, the reactive power increases.

4) generator stator voltage increases, the stator current is reduced. The stator current is reduced because the output active power of generator suddenly disappear cause, although the output reactive power increases, and to draw a small amount of active power from the system, but the total is still reduced stator current. Due to the decrease of stator current, voltage drop current in the stator reactance on the decrease, so the stator voltage rise. Because the generator and the system is connected to the transportation system, generator reactive power increases, the generator demagnetization effect increases, the stator voltage automatically reduce the maintain generator voltage and the system voltage balance.

5) generator excitation circuit instrument indication is normal, the system frequency may be reduced. Because of the excitation system is not changed, so the excitation circuit of each meter indicating normal. The generator phase operation not only active power output, but also from the system to draw a small amount of active to maintain its synchronous operation. When the generator is the total load system of large proportion, because the system active power is insufficient, make the system frequency drop.

2 generator into processing condenser operation:

The generator into the condenser operation, the generator itself, does not have what harm, but does not allow for long-term operation without steam. This is because the runtime, blade and air friction will cause overheating, so that the exhaust temperature rises quickly, so the generator does not allow continuous phase modulation operation.