Distance relay finds its application in electrical transmission systems. Basically to prevent the systems associated in generation , distrubution & the transmmision line from fault that might occur during power distribution . This distance relay will detect the fault as well as the fault location.The relay derives the impedance depending on the voltage, current signals & based on this value, finds the distance from the relay location to the fault point. Developed for Aluminum Industries,Thiruvananthapuram, Kerala, India.

Highlights

• System consists of signal conditioning circuits, sample & hold circuits, ADCs, microcontrollers & DSPs,CTs & PTs
  Very linear CTs & PTs to step down the current & voltage
• Signal conditioning circuits consists of filters to chop out the unwanted signals, variable gain amplifiers to amplify the signal to a desired level
• Sample & hold circuit can adjust the sampling rate depending on the frequency of the input signal & can hold the data for the ADC to read it
• 13 bit ADCs, used for A/D conversion
• 16 bitMicro-controllers are used as front-end wich does the data acquisition & gets relay settings from the pheripheral devices
• DSPs 16 bit, 12 Mhz. which does all data processing, fault location calculations & gives the final trip if there is a fault
• Calculations are done for every sample
• Fourier algorithm implementation to get the fundamental value of the signal
• Fault detection with minimum amout of time
• Makes use of quadrilateral characteristics for fault location & detection
• Power swing blocking is provided
• User selectable time & other settings are provided