Calibrating high voltage impedance bridges with low voltages and digital

• Autor(a) principal: Kyriazis, Gregory Amaral
• Data de Publicação: 2010
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional do INMETRO
• Texto Completo: http://hdl.handle.net/10926/1643

A calibration system for automated high-voltage current-comparator-based capacitance and dissipation factor bridges is presented. The method saves a lot of time and is much flexible as it does not use or require high voltages and high voltage standards. For the calibration, two sinusoidal currents at power frequencies are synthesized with two synchronized signal generators and two resistors, and injected into the bridge inputs. The capacitance ratio and dissipation factor simulated by these currents are calculated from an ac voltage ratio estimated from the digitized data, together with the impedance ratio of the resistors. The ratio and phase displacement of the two sinusoidal voltages are adjusted to simulate any capacitance ratio from 0.1:1 to 100:1 and any dissipation factor from zero to +/- 1 (or more). The method has been applied with success to the calibration of commercial electronic bridges.