Modern fault location technique for the utility

Using a phase-differential busbar protection for switchgears of power system facilities

“…PDBP has 2 basic settings: blocking angle j bl (to distin guish internal SC from other modes of mains) and the level of formation of pulses i у (used in the phase modulation process [4,5]); PDBP startup in shortterm match of current phases of connections, due to some disturbance that has caused current reversal in one or several phases (or due to distortion of the secondary current of one or several connections), and the pro tection is triggered only when confirming the longterm syn phasis of these currents for some time specified by the control setpoint (characteristic only for internal SC or damage of cur rent circuits with the loss of the "blocking signal"); use of the compensation algorithm for angular errors, saturated MCTs, which can reach up to 7 ms (126 degrees for the current through the "zero") and more, depending on the parameters of the power supply system and the parameters of MCT, the sign and the value of the residual induction of mag netization, etc. [6,7]; in design and principle, the protection is not identical to the phasedifferential protection of 110-750 kV overhead lines (DPLP) [3], significant differences are due to the feature of the protected object and the rejection of using the starting unit by current and distance unit; the phase modulation process also has certain peculiarities in connection with the imple mentation of the algorithm for compensation of angular errors for the saturated MCTs [8];…”