Computation of fault currents and voltages along a multigrounded neutral power line having multiple phase conductors

Abstract

A procedure is described for determining the distribution of currents and voltages to remote earth along a faulted multigrounded neutral power line that has an arbitrary number of phase conductors. Line capacitances are omitted; otherwise, the parameters of the line, its sources, and the locations and impedances of the grounds are not restricted. The open-circuit impedance matrix of the line at the fault site is derived first; from this, the local voltages and currents are obtained. These are utilized to compute the voltages and currents elsewhere along the line. All network analyses that are required by the procedure are confined to a simplified "neutral ladder" network. The neutral ladder is determined by the neutral conductor and the paths to ground from it; however, it is independent of the phase conductors and all of the mutual impedances of the line. The neutral ladder reduces the computational effort required for numerical evaluations and offers insights into characteristics of the voltage and current distributions along the neutral conductor. As an example, an analysis of a faulted, doublefed, three-phase line is provided.

Short‐circuit current distribution analysis using a network model based on a 5×5 primitive matrix

“…Several short-circuit solution approaches for fault current distribution have been introduced under the 4×4 paradigm, ie, double-sided elimination method, 5 driving-point impedance technique, 6 ladder circuit solution, 7-9 single division factor, 10 two-port theory, 11 and nodal admittance methods. [12][13][14][15][16][17] Special purpose application software such as OpenDSS, 16 WinIGS, 18 and CDEGS 19 include 5 • Gooi 6 • Popovic 7 • Levey 8,9 • Kiessling 10 • Buccheri 11 • Zou 12 • Penido [13][14][15] • OpenDSS 16 • Klucznik 17 • WinIGS 18 • CDEGS 19 • Acharya 20,22 • Oka 21 • Chen 23 • Kersting 3 • • Anderson 24 • • Ciric 25,26,28 • specific modules to determine current fault distribution in substations and lines. Other general-purpose application tools such as electromagnetic transients program (EMTP) [20][21][22] and personal simulation program with integrated circuit emphasis (PSPICE) 23 : have been also used to tackle the problem.…”

Transferred voltages in multigrounded systems

“…For example, in [2] an overview of many of the relationships between neutral currents, ground currents, electrode impedances, and voltages that are found in the operation of multigrounded wye distribution systems is presented, and examples in very simplified conditions are given; in [3] the goal is a method to get a simplified "neutral ladder" network that can confine all the analysis required; in [4] the distribution system is modeled by a resistive network to provide neutral-to-earth potential profiles under various conditions of loading; in [5] a simplified computer model implemented on EMTP leads to the conclusion that customers' grounding systems determine the impedance of multigrounded neutrals in an area characterized by a high soil resistivity and low customer density over long distances; in [6] the analysis is focused in the operating conditions of multi-grounded three-phase four-wire distribution systems under unbalanced situations.…”

Ground potential rise of multi-grounded neutral and shield wires in joint systems

“…In the past, a lot of studies have been done for single circuit multi-grounded configurations and a great deal of literature is available [1][2][3][4][5][6][7][8][9][10], but limited work has studied the composite systems comprised of multiple multi-grounded conductors. Mostly computer-based methods were preferred for the studies of multigrounded systems.…”

“…Computer models were used to estimate the GPR of the multi-grounded neutral (MGN) in [2][3][4] and power flow studies were performed in [5][6][7]. Analytical approaches for the GPR analysis were proposed in [8][9][10]. The GPR assessment of multi-grounded communication cable bonded with power line's neutral wire was performed in [9].…”