Resumo

FERNANDEZ-MORALES, Flavio Humberto  e  ENRIQUE-DUARTE, Julio. Monitoring electric variables of three-phase power generators. Entramado [online]. 2014, vol.10, n.2, pp.314-321. ISSN 1900-3803.

Three-phase power generators are machines which are extensively used as electric power sources. They are commonly found in combination with alternate power supply sources such as generating sets, small hydroelectric power facilities, and wind power generators. These low- and medium-power generators are not usually provided with suitable devices that allow users to determine whether or not they are operating properly. This paper describes the design and implementation of a system for measuring variables associated with three-phase power generators. Two modules were developed: a voltage-based module that is also used for measuring the frequency and checking the phase sequence, and a second model that measures electric current. Data is processed using PIC 16F873 micro controllers to which measuring transformers and other signal conditioning devices were adapted. Each module makes it possible to view the variables on a liquid crystal display. The system operates in the range of 22 to 150 VAC with a maximum relative error of 7.6%. The current can vary by up to 100 A with a maximum relative error of 6.3%.

Palavras-chave : Three-phase power generator; voltage measurement; electric current; calibration; signal conditioning.

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