Relay protection current/voltage sampling and signal conditioning can be performed using GX7606/GX200, replacing AD7606/OP200/OP2277

Relay protection is a technical means and device that can quickly, automatically, and selectively isolate, cut off, or issue alarm signals from faulty or abnormal components or equipment in the power system when a fault or abnormal operating state occurs.

Relay protection is the defense line for the safe operation of the power system. When monitoring the occurrence of faults in the grid current and voltage signals (such as short circuits, overcurrent, overvoltage) in real time and quickly cutting off the fault circuit, this process requires ensuring the accuracy, response speed, and anti-interference ability of current/voltage sampling. The synergistic combination of analog-to-digital converter GX7606 and operational amplifier GX200 is an ideal choice for current/voltage sampling and signal conditioning in relay protection.

The eight channel 16 bit 200kSPS analog-to-digital converter GX7606 integrates 8 independent sampling channels in relay current/voltage sampling, supports 200kSPS synchronous sampling rate, ensures no deviation in the phase relationship of current and voltage signals, and meets the accuracy requirements of protection algorithms such as power calculation and phase comparison. The chip supports a true bipolar input range of ± 10V and ± 5V, suitable for PT/CT output. The input reference noise is as low as 2.5 μ Vrms (0.1Hz to 10kHz), and the effective number of bits (ENOB) is up to 14, ensuring the sampling accuracy of small signals (such as no-load current) (error<0.2%).

Anti interference and industrial grade reliability: The input clamp protection can withstand voltages up to ± 30V, and the ESD level can reach 8kV. For applications with low throughput requirements, the GX7606‘s built-in oversampling mode and flexible digital filter can be used to improve noise performance, with built-in power monitoring and overheating protection functions. The working temperature is -40 ℃ to 85 ℃, and it can be directly installed in the sampling module inside the high-voltage cabinet.

GX200 is a 36V dual channel high-precision operational amplifier that directly processes transformer output signals in relay protection signal conditioning, and has strong stability in high voltage environments. GX200 provides low noise, wide output voltage swing, and its characteristics include ultra-low offset voltage and offset voltage temperature drift, low bias current, high common mode rejection, and high power supply rejection. Has excellent performance within the rated operating voltage range of ± 2.25V to ± 18V. The initial offset voltage of GX200 is very low, with a maximum of ± 100 μ V, so in most cases no external adjustment is required.

GX200 is easy to use, with no phase reversal or overload issues. It has unit gain stability and provides excellent dynamic performance under a wide range of load conditions. At the same time, different channels of the chip have completely independent circuits, achieving extremely low crosstalk.