If the voltage you want to use is not very high, you can add a step-down transformer to the output end of the generator to obtain a high current power supply. This is how the current power plant works. The electricity produced by the power plant is first boosted, after boosting, is to use small current and high voltage to send energy outward, the purpose is to reduce losses, but before reach low voltage electrical appliances, the voltage must be lowered. thrice. The power is constant, the voltage is high, the current supplied is low and the total power remains unchanged.
When the generator is operating at low load, the three-phase current suddenly drops about 100A from time to time, then recovers immediately. What is the reason ?
Once the generator is connected to the network and closed at the same time, the active power and the pureactive power are basically zero. At this time, the induced potential of the generator stator is equal to the terminal voltage. If the active power is increased first, this can cause an induced potential lower than the terminal voltage, causing reactive power to flow back, which is detrimental to the stable operation of the generator. Therefore, after connecting to the grid, a small excitation is usually added to make the power output state reactive. The reactive power band can be determined by referring to the terminal voltage. As active power increases, reactive power decreases. This is a normal phenomenon (except for automatic excitation). Therefore, the reactive power should be adjusted according to the active power, and the power factor is generally kept between 0.8 and 0.9.
This is due to fluctuating power grid load and is nowbut normal.
Reason: The condition for the generator to send power to the grid is that the voltage is slightly higher than the grid voltage, otherwise no power will be sent or used.
Analysis: When the 10MW generator operates at low load (3~4MW), the excitation system operates in a low excitation state, the magnetic circuit is not very saturated and the transient component of the reaction induces reactance is too large, causing excitation. The system response speed decreases. When the grid voltage is higher than the generator voltage, the amount of energy supplied decreases, i.e. the generator current decreases. The excitation system cannot respond, resulting in strong excitation and a sudden drop in reactive power. The above parameters automatically recover after fluctuation, indicating that the generator excitation system is responding, proevoking an increase in the voltage at the generator terminals, a recovery of current and a recovery of reactive power.
During the whole process, the door opening does not change and the main steam parameters do not change, because the current drop of 70 A is very small for the adjustment accuracy of the steam generator. 10 MW, therefore of the system. will not change working conditions.
I stopped the machine once and checked the excitation system. No problems were noted. It can be seen that this generator phenomenon is a problem of insufficient response speed, but for generators that do not work. nominal values, this discrepancy is understandable. Under full load conditions, the transient component of the generator armature response will return to normal and the system response speed will also return to normal.
Conclusion: This phenomenon is normal.
Fujian CountyZherong Huayuan Power Equipment Co., Ltd.