Low-Latency Distance Protective Relay on FPGA

Abstract

The need for high-speed multi-function protective relays in both traditional transmission systems and the new emerging paradigm of the smart grid is growing. As a widely used protective scheme for transmission lines, a distance relay's high speed and reliable operation to clear faults is essential. This paper proposes a real-time low-latency hardware digital distance protective relay on the field programmable gate array (FPGA). Taking advantage of inherent hard-wired architecture of the FPGA, the proposed hardware distance relay design is paralleled and fully pipelined to achieve low latencies in various relay modules which are developed in textual VHDL language. This low-latency feature allows fast operating and data throughput so that the relay can handle high-frequency sampled data and reach higher computational efficiency. In addition, the parallelism and hardwired architecture of the FPGA makes the design more reliable in computation than the sequential software-based numeric relay. The FPGA-based distance relay can operate on both phasor-based signals and instantaneous signals with 2.09 and 0.35 latency respectively based on the clock frequency of 100 MHz. The hardware relay is tested in real-time by feeding it with generated faulted current and voltage data for typical faults and the relay response recorded. The results demonstrate the speed and effectiveness of the hardware distance relay.

A novel and comprehensive single terminal ANN based decision support for relaying of VSC based HVDC links

“…Whilst the algorithm could be implemented with an FPGA [6], [27], it is also well within the capabilities of the DSP chips in modern numerical relays.…”

Design and development of travelling‐wave‐frequency‐based transmission line fault locator using TMS320 DSP

“…In this context, the software packages developed to determine the fault instant in different relay designs have been tested using FPGA [5] and DSP [6,7]. Some completed software packages have been tested in real time in [8,9] to both determine faults and classify the fault type with the use of FPGAs.…”

“…In the literature, the first step in all software packages developed to protect the transmission line is to determine the instant of fault occurrence. Many different approaches have been used to determine the fault instant [5][6][7][8][9][10][11]13].…”

“…In one previous study [5], the fundamental magnitudes of the phase currents were calculated by application of the full-cycle discrete Fourier transform (FCDFT) to the phase currents. In this approach, when these calculated magnitudes exceed a certain level, the fault instant is determined.…”

“…Since very few have been tested in real time [11]. In [5], the software which is based on FFT and certain rules was tested with FPGA to find fault detection. In [8], the software which is based on WT and certain rules was tested with FPGA to find fault classification and fault detection.…”