Analog Devices Improves the monitoring and protection performance of smart grid transmission and distribution equipment

     A leading global provider of high-performance signal processing solutions has introduced a family of 24-bit data acquisition system-on-chip (SoC) products to improve the performance of protection, monitoring and power quality measurement Devices that manage power transmission and distribution within smart grid systems. The AD7770 enables higher performance and smaller protective relays, while the AD7771 helps power quality measurement devices detect early grid failures. The AD7779, the third generation SoC in the product family, ensures fast power-on of circuit breaker units.

     The three products in the AD777x family deliver the industry's best combined dynamic range and data output performance, with eight synchronous sampling channels to measure the output of current and voltage sensors in three-phase power applications. Each SoC channel achieves a dynamic range of 112-dB at 8 kSPS, enhancing protection and measurement capabilities in a single ADC channel. The AD777x product family also incorporates A sampling rate converter, simplifying the design challenges of power quality devices and making it easier to meet IEC61000-4-30 Class A standards.

     The AD777x series has built-in programmable gain amplifiers (PGA) for adjusting a variety of sensor outputs, enabling system designers to use a common platform to meet a variety of applications that may have different accuracy requirements and input sensor types, including current transformers, voltage transformers, and resistance strings. In addition, the AD777x series reduces the total system cost by reducing external components such as signal conditioning amplifiers and phase locked loops (PLL). The complete AD777x series also includes sampling rate converters that fine-tune the sampling rate to ensure line frequency consistency in the 50-Hz (-15%) to 60-Hz (+15%) range, with variations within 0.01 Hz. This is the requirement of IEC61000-4-30 Class A power quality standard.

     The new products also feature a variety of on-chip diagnostics to help simplify the design process and enable the end devices to be certified to the Safety Integrity Level (SIL). There is an additional low-resolution SAR ADC channel that utilizes independent power operation to provide data for system and chip diagnostics, improving data integrity and enhancing the overall reliability of the system. The AD7771's high dynamic range and high sampling rate reduce fast Fourier transform (FFT) background noise, which enhances detection of anomalous-frequency spurious, signals electrical faults, and enables early warning detection and preventive maintenance measures with power quality measurement equipment.