digital display time relay
Time-Time-Time Switching Network TTT
digital relay
数字式继电器
数字式保护装置
智能电器监控单元
数字式保护
数字中继
微机保护
继电保护设备
数字继电器
digital relay and monitoring
Digital Relay Protection
digital relay testing instrument
digital time basic corrector
digital time delay filter
digital time domain induced polarization receiver
digital time series analysis
digital time study board
Fully Digital Relay Protection
Integrated Digital Relay