外文翻译--电力系统中的励磁系统

Power system of excitation system

In the power system, the big unit is usually much return high-voltage transmission through to the distance, to reduce power load center, usually by without loss of wattless situ balance. But this way is easy to destruction, causing voltage instability. Excitation control system is an important part of synchronous generator power system, to ensure normal operation conditions voltage electricity conveying rate between basically unchanged, ensure its reactive load distribution, improve the power system static stability, and because has forced excitation device, in power system is at fault, can quickly will generator excitation current increasing rapidly, so as to ensure protection device and reliable sensitive, improve the power system dynamic stability.

A, excitation control principle

Synchronous generator excitation system is by exciter, generators, voltage regulator components, in this system, excitation controller detection generator voltage of UF and machine with UF reference voltage compared to UC voltage difference (UC - UF), through comprehensive amplification UK, obtaining control voltage UK = K (UC - UF). By this type, it is easy to see when the generator voltage of UF rise, machine will reduce the voltage difference, so that, through comprehensive amplification the control voltage UK also can be reduced, so, exciter excitation current and voltage of generator rotor will fall subsequently, such, generator machine with the decrease of voltage of UF also, so that the voltage across the machine generator disturbance was offset rising. Therefore, excitation system is raising power system stability operation, maintain and improve the synchronous motor voltage level power limits and power system transmission power, and other functions. In addition, in this system can also according to the actual need additional damping, fuzzy neural auxiliary control function. The main part of the excitation control, its effect is excitation adjuster is feeling generator voltage change, and send to excitation control command of the power unit controlled, power unit also only in excitation receives excitation adjuster control command will change its output excitation voltage.

Therefore, on the one hand, excitation regulators should be able to reflect the generator voltage high voltage to maintain power conveying rate in a given level, can reasonable distribution of reactive power generating units, and should have forced excitation function to rapid response system fault, in order to improve the transient stability and improve system operation conditions; On the other hand, the excitation of the power unit must have plenty of reliability, and have enough regulation capacity, with enough excitation electricity honest value and voltage up speed. Excitation system model, according to the different categories can be divided into many different kinds. Our common excitation system model mainly dc excitation system, ac excitation system

And and the static excitation system (including an excitation and the complex in power system shunt. The actual analysis, usually adopts simplified practical model. Meanwhile, the general excitation system in additional quick excitation control mode, its role is to a fault occurs quickly capture of the change of the signal generator voltage controlled, and, in order to control generators turn bad swing, improve the transient and static stability. For fast control generator bus voltages, must improve the excitation system

Speed of response. Therefore, it is necessary to improve excitation system (including automatic voltage regulator A VR) adaptation performance and of excitation system in peak voltage.

Second, excitation system on power system stability influence Excitation system directly affect the safe operation of the generator, its technical performance is low will give unit operation caused great Ann .All the hidden trouble. To meet the power system of the power quality high standards of requirements, ensuring the long-term security, stability generator to run, must adopt the advanced scientific excitation system.

1.1 various excitation system comparison analysis

Synchronous generator excitation system it excitation SCR major strength