Reference Design to Measure AC Voltage & Current in Protection Relays w/Delta-Sigma Chip Diagnostics

1 января 2018

The TIDA-00810 reference design accurately measures analog inputs performance and includes chip diagnostics to help identify power systems failures early by using a highly accuracy AC voltage and current measurement analog front end (AFE) and a four-channel, 24-bit simultaneously-sampling differential input Delta-Sigma ADC for measurement over wide dynamic range. The ADC is configured to measure 0-5 V unipolar. The inputs are scaled to ADC measurement range using a fixed gain amplifier with 2.5 V DC output level shift. The AFE can be used to measure output of a current transformer, potential divider with analog isolation and Rogowski active integrator. The AFE uses 10-Bit low resolution successive approximation register (SAR) ADC in parallel with a 24 bit ∑-∆ ADC for ADS131A04 diagnostics.

Особенности

Data acquisition and diagnostics coverage provided using 24-bit ∑-∆ ADC and 10/12-bit SAR ADC Output from the ∑-∆ ADC is validated by comparing it with SAR ADC – peak/RMS value is used for validation ∑-∆ ADC reference output or external reference is monitored using a comparator Current measurement accuracy is verified using current transformer and Rogowski coil with hardware integrator Voltage measurement accuracy is verified using a potential divider (PD) without and with an isolation amplifier