Senkron makinanın kararlılık incelemesi

Abstract

Bu çalışmada sonsuz güçlü bir şebekeye bağlı senkron makina, iletim hattı ve tahrik makinasmın ( Buhar türbini) durum uzay modelleri çıkarılmış ve güç sistemininde bir bozucu etki olması esnasında sistemin davranışları bozucu etki öncesi sonrası ve sırasında incelenmiştir. Sisteme eklenen otomatik gerilim regülatörünün sistem kararlılığı üzerindeki etkisi incelenmiş ve daha sonra sistem kararlılığının artırılması amacıyla adaptıf kontrolörlerden biri olan öz ayar regülatörü ( self-tuning regülatör) sisteme eklenerek çıkış değişkenleri tekrar incelenmiştir. Senkron generatör ve uyarmayı içeren durum uzay modeli ikinci bölümde, türbin, devir sayısı regülatörünü içeren durum uzay modeli üçüncü bölümde, uyarma sistemlerinin tanıtılması türleri ve otomatik gerilim regülatörleri dördüncü bölümde, adaptif kontrol sistemleri hakkında genel bilgi, tekrarlamalı en küçük kareler yönteminin tanıtılması ve öz a- yar regülatörleri bakında genel bilgi beşinci bölümde ve son olarakta Fortran 77 bilgisayar programıyla sistem simülasyonlan ve çıkış grafiklerinin alınması altıncı bölümde verilmiştir.In everyday language, to 'adapt' means to change a behavior to conform to new circumstances. Intuitively, an adaptive regulator is a regulator that can modify its behavior in response to changes in the dynamics of the process and the disturbances. Since ordinary feedback has been introduced for the same purpose, the question of the difference between feedback control and adaptive control immediately arises. Over the years there have been many attempts to define adaptive control. At an early symposium in 1961 a long discussion ended with the following suggested definition: ' An adaptive system is any physical system that has been designed with an adaptive viewpoint.' A new attempt was made by an IEEE committee in 1973. It proposed a new vocabulary based on notions like self-organizing control ( SOC ) system, parameter adaptive SOC, performance-adaptive SOC and learning control system. A meaningful definition of adaptive control, which would make it possible to look at a regulator hardware and software and decide if it is adaptive or not, is still lack ing. There appears, however, to be a consensus that a constant-gain feedback is not a adap tive system. X7V Synchronous machines are nonlinear and subject to continuous changes and dis- turbances. it is desirable to design the structure and parameter values of a controller which will function satisfactorily for the various operating conditions. To achieve an acceptable performance the design of the voltage regülatör structure and selection of parameters have to be done carefully. it inevitably involves large amounts of experimentation on the machine. Tuning procedures provide optimum performance for the worst conditions, so that performance will be satisfactory över a wide range of operation. Adaptive regulators are very suitable for plants whose operating conditions change. The situation is depicted in Fiğ. 1. If the plant has öne set of parameters the elements in the controller should have an optimum set of values to achieve an optimum performance of the output. If the plant parameters change, the controller parameters will no more be optimal unless they also change accordingly. Adapter regulators satisfy this need for changing the controller parameters. < disturîpance *(Z) * Controller » Power amp. -» Blant R->^n^_J-l T^-J Fiğ. l. The controller with variable parameters for a varying plant. A popular regülatör which can change the controller parameters to give optimal performance under varying operating conditions is called the self-tuning regülatör ( STR) and is shown in Fiğ. 2. An STR is a digital adaptive regülatör which has the facility to change the controller parameters continuously by tracking the operating conditions in real time and modifying the parameters accordingly. in applying the STR theory to the excitation control problem, it has been found that due to the computational burdens imposed upon the process computers, particularly the microcomputers, the sample time required tends to be too large to track machine dynamics. To avoid this a dual rate sampling model is suggested. Multirate control system are known to give better perfbrmance. Comparison of performance is made with the STR and also with an analog AVR designed following the widely accepted guidelines. it is demonstrated that the proposed regülatör gives superior performance. X serve the purpose. A change in the load supplied to the system will affect the terminal voltage as well as the load angle and A