Generator Reverse Power Maintenance

Setting calculation of steam turbine inverse power maintenance is to confirm the operation power Pdz and action delay T of the maintenance.

1. Action power of Pdz set turbogenerator inverse power maintenance action power can be calculated according to the following formula: Pdz=(Krel*P1)/η Pdz- inverse power maintenance operation power Krel- reliability coefficient, take 0.8 P1- the power consumed by the turbine to maintain synchronous rotation speed after the main valve is closed, the size of this power is related to the structure and capacity of the turbine, It is also related to the structure of the main steam system of the turbogenerator (pipeline structure and whether there is bypass pipeline, etc.). Generally, the rated power is 1.5~2% η- the power of the generator when the generator drags the turbogenerator to rotate, and 0.98~0.99, so: Pdz≈ (1.2~1.6%) PN PN- the rated power of the generator. In practice, Pdz= can be 1-1.5% PN.

2.Action delay generator inverse power maintenance action delay, should be in accordance with the steam turbine generator after the main valve closed allowed to operate time to set, the allowed time is generally 10~15min. The calculation and operation practice indicate that when the steam turbine steam system has bypass pipe, the operation time should be longer. Therefore, if the maintenance action delay is set according to the time allowed to run after the main steam turbine valve is closed, 5~10min is advisable. After action, it is applied to disengage magnetic field.

In addition, the large turbogenerators in operation mostly use reverse power maintenance to start the program trip loop. At the moment, the action time usually takes 1~2s. For program-controlled inverse power maintenance, because the operation time is short, in a very short time after the main steam valve point is closed, due to the inertia of the turbine and generator, the practical inverse power may be very small, so the fixed value of the inverse power should not be greater than 1%PN.

An introduction to the principle 

When the generator has reverse power (external power points to the generator, that is, the generator becomes the motor condition), the reverse power maintenance operation circuit breaker trips. Demand collects three-phase voltage and two-phase current signals.

Because of the different forms of primary energy, different generators can be made. Using water resources and water turbine cooperation, can be made into water turbine generator; Because of the difference of reservoir capacity and head drop, hydro-generators with different capacity and speed can be made. Using coal, oil and other resources and cooperating with boilers and turbo-steam engines, turbo-generators can be made, which are mostly high-speed motors (3000rpm). In addition, there are all kinds of generators using solar energy, wind energy, atomic energy, geothermal energy, tidal energy, biological energy and so on. In addition, because the generator operation principle is different and divided into dc generator, asynchronous generator and synchronous generator. In widespread use of large generators are synchronous generators.

Guangxi Dingbo Power Equipment Manufacturing Co., Ltd. established in 2006, is an manufacturer of diesel generator in China, which integrates design, supply, commissioning and maintenance of diesel generator set. Product covers Cummins, Perkins, Volvo, Yuchai, Shangchai, Deutz, Ricardo, MTU, Weichai etc. with power range 20kw-3000kw, and become their OEM factory and technology center.