Monitorização e controle em tempo real baseados em microcomputador para um microgerador síncrono e motor CC.

Abstract

The main contribution o f this study is the creation of a environment for real implementation o f power system controllers. Also, it contributes to dynamic stability studies as well to the development of measurement instruments based on microcomputers and digital controllers for generator and turbine. To realize this work, a set of micromachines composed of a 3 K V A microgenerator and a 5,5 KW DC motor have been used. They were constructed in reduced scale to represent a realistic generator/turbine system. To run up the micromachine a control, measurement and protection panel has been implemented. The panel has a synchronizing system with a distribution energy system through transformer and microtransmission line. In this way, one has a reduced model which allows real time stability studies. Using a I BM -386 microcomputer, a software called "SISMOCON" for excitation and speed control has been developed. The software allows line recording and visualization o f electric variables. To operate the micromachines through the keyboard, a man-machine interface has also been developed. The following digital controllers have been implemented: A PI controller for the microgenerator terminal voltage control and two PI controllers with cascade operation for DC motor speed and current control. The criterion for tunning the digital PI controllers is based on optimal damping and dominant pole cancelation. To help the microgenerator dynamic process evaluation, accurate and dedicated transducers based on microcomputer have been developed. These transducers are: Load angle, electric frequency, phase angle, power factor. To improve the microgenerator stability and to control the local network energy supply, active and reative power limiters were developed. These limiters allow the micromachines to work with security within a limited region o f the machine capability curve. Finally a compensation technique to improve the machine stability through the excitation system has been developed.