The Research Of The Single Asynchronous Generator's Frequency And Voltage

Compared with the synchronous generator, the asynchronous generator has virtues such as simple structure, reliability, lower price, higher efficiency and it is easy to realize on duty without people. It has predominance in the field of distributed generation. The load's fluctuation can result in big range of the single asynchronous generator's frequency and voltage, even to result in the breakdown of the system. Because of that, it has to adopt one project to control the frequency and the voltage from both the technical and the economical aspects. It is also to ensure the stability of the system so that it can create conditions to the asynchronous generator's extension and application. No matter it is asynchronous generator or synchronous generator, it is a big problem to stabilize the single asynchronous station's frequency. The normal asynchronous generator depends on the stator's excitation so that the reactive power and the voltage's control is more difficult. The method of single asynchronous generator's frequency and voltage control is fit to synchronous station absolutely, offering technical support to the development of the distributed generation. The dissertation researches the problems as follows: (1) Analysis the static and dynamic characteristic of the asynchronous generator dynamic characteristics, comparing with the synchronous generator from the aspect of small fluctuate and big fluctuate. (2) Analysis the existing asynchronous station's method of voltage control and the limitation in the engineering. (3) Analysis the existing asynchronous station's method of frequence control and the limitation in the engineering. (4) The dissertation puts forward the method of controllable heat saving load and adjustable capacitor to adjust the frequence and voltage, in order to simplify the control . It also analysis two methods, one is to maintain the frequence, the other one is to maintain the voltage. The dissertation builds mathematic system model and analysis the result. a) The quality of the load's frequence, voltage and the stability under the circumstance of big fluctuation. b) Compare two methods in order to know which one is better, one is to maintain the frequence, the other one is to maintain the voltage. The research indicates that the method of controllable heat saving load and adjustable capacitor has the advantage of simple structure and fewer investment, it can stable the frequence and voltage better. The method, aiming to maintain the frequence, is more better. It can stabilify the frequence as well as less excursion of the voltage in the same time. This method can be used to single asynchronous station widely to solve the control problem of frequence and voltage.