Abstract: Three phase power flow analysis of an unbalanced power distribution system decouples voltage changes resulting from nodal admittance matrix into one contribution from a real part, conductance matrix, and other contribution from an imaginary part, and a susceptance matrix. A first voltage change and second voltage change resulting from conductance and susceptance matrices are determined respectively. The voltages of a node of the power distribution system are determined as a combination of first and second voltages.

Abstract: A method determines a location of a fault in a faulty feeder section of an ungrounded power distribution system based on a type of the fault and the type of the faulty line. The method determines, if the faulty line is the lateral and the fault is phase-to-phase or double-phase-to-ground fault, the fault at a first point on an un-faulty phase of the lateral where a fault current equals a load current. The method determines, if the faulty line is the lateral and the fault is the three-phase fault, the location of the fault at a point with a minimal difference between imaginary parts of equivalent fault impedances. The method determines, if the faulty line is the mainline, the location of the fault at a point partitioning the faulty segment on two sub-segments with a ratio of lengths determined based on the voltages at the buses of the faulty segment.

Abstract: A method determines a location of a fault in a faulty feeder section of an ungrounded power distribution system based on a type of the fault and the type of the faulty line. The method determines, if the faulty line is the lateral and the fault is phase-to-phase or double-phase-to-ground fault, the fault at a first point on an un-faulty phase of the lateral where a fault current equals a load current. The method determines, if the faulty line is the lateral and the fault is the three-phase fault, the location of the fault at a point with a minimal difference between imaginary parts of equivalent fault impedances. The method determines, if the faulty line is the mainline, the location of the fault at a point partitioning the faulty segment on two sub-segments with a ratio of lengths determined based on the voltages at the buses of the faulty segment.

Abstract: Three phase power flow analysis of an unbalanced power distribution system decouples voltage changes resulting from nodal admittance matrix into one contribution from a real part, conductance matrix, and other contribution from an imaginary part, and a susceptance matrix. A first voltage change and second voltage change resulting from conductance and susceptance matrices are determined respectively. The voltages of a node of the power distribution system are determined as a combination of first and second voltages.