Bus differential protection in industrial systems with generators connected directly to the main distribution bus

Integrated busbar protection scheme utilizing a numerical technique based on coherence method

“…As a result, the technique in [20] introduced an adaptive busbar differential relaying scheme based on the form and ripple factors of the measured current signals, which modified the slope of differential relay characteristic during the state of external fault with CT saturation extent, and accelerated the relay operation in the case of internal faults. The drawbacks of some existing BB protection techniques [2, 6, 11, 14] are outlined as follows: Conventional BB differential overcurrent relays have open‐tripping characteristics, where the values of differential and restraining currents are not limited, even though they are in per‐unit values, The sensitivity and security of the differential overcurrent relay are controllable using the low setting (pickup) value of the differential current computed for each cycle, as well as the change of blocking zone located inside the relay tripping characteristic. However, only one numerical value of the slope/restringing factor is selected; therefore, the relay characteristic type is fixed (without adaptation of blocking and tripping zones). The differential overcurrent relays need an additional algorithm/device of CT saturation detection to prevent the relay operation in the case of external fault with CT saturation extent, Multi‐functions digital relay requires various protection algorithms; hence, different types of mathematical models are used, Additional low‐pass filters are essential for avoiding the effects of power system harmonics.…”

“…However, there is always a need to develop innovative and efficient methods of busbar protection. References [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] present some modern techniques, which utilize sophisticated algorithms, to provide fast busbar protection and reliable performance during CT saturation. Some busbar protections based on Travelling Wave (TW), which used the transient fault information to avoid CT saturation effects and improve the speed and sensitivity of the protective relay [7][8][9].…”

“…Some approaches applied statistical techniques such as alienation model [12,13]. It is known that the percentage differential protection uses restraint current to prevent the differential relay from false tripping [14]. A combination of Support Vector Machine (SVM) and S-transform were used for BB protection, as presented in [15].…”

“…As a result, the technique in [20] introduced an adaptive busbar differential relaying scheme based on the form and ripple factors of the measured current signals, which modified the slope of differential relay characteristic during the state of external fault with CT saturation extent, and accelerated the relay operation in the case of internal faults. The drawbacks of some existing BB protection techniques [2,6,11,14] are outlined as follows:…”