Comprehensive 3‐capacitors model for partial discharge in power cables

Abstract

PurposeThe paper proposes and presents a comprehensive and integrated circuit model for investigating the behaviour of partial discharges occurring in voids inside the solid insulations of medium and high voltage cables.Design/methodology/approachThe model is based on the well‐known three capacitors model, which is remarkably improved to handle physical parameters such as cavity size, position, shape and pressure, environmental parameters such as cable temperature, in addition to operational parameters such as the contributions of the avalanche of free electrons inside the cavity through considering stochastic time delays.FindingsA complete, flexible and reliable model for partial discharges in voids inside the solid insulation of medium and high voltage cables is presented whose output agrees with experimental reported results.Research limitations/implicationsThe proposed model deals only with single voids, and the semiconductor layers in the insulation of cables are not considered.Practical implicationsThe model can be used in different physical, environmental and operational conditions in order to investigate the characteristics of partial discharge signals to be used as the bases for partial discharge detection and classification in power cables.Originality/valueThis paper presents a novel comprehensive and integrated circuit model with controlling functions to propose the behaviour of partial discharge occurring in voids inside the solid insulation of power cables. The model provides the contribution of geometrical parameters of the void, and operational conditions such as cable temperature and source frequency in partial discharge analysis.

Numerical modeling of partial discharges in a solid dielectric-bounded cavity: A review

“…Table 2 summarizes various capacitance models and relevant explanations, in which resistors are sometimes introduced to simulate the conductivity of insulation and discharge channel. When a PD takes place, the cavity resistance will be largely reduced, so a lot of researchers use a time-varying resistor to model the PD development [30,37,49]. In addition, circuits including three resistors parallel to capacitors are constructed whereby the effect of charge dissipation on PD can be considered at both AC and DC voltages [38,50].…”

“…Figure 9 shows the procedure of PD simulation, in which the combinations are indicated by the same color. Although the expression of Richardson-Schottky has been applied to capacitance models [37], it is far-fetched to consider free electron supply by volume generation and surface emission, because the both are derived based on the field theory, whereas the capacitance models are on the point of view of circuit.…”

A comprehensive circuit model for partial discharge activities in cable insulation due to electrical treeing

“…c(T) is defined by the following relation [3], to provide expected results when the cable temperature varies:…”

“…This restraint condition is modeled through employing a probability function, for any time as t after the instant when the voltage exceeds the breakdown level (t b ), which is [3]:…”

“…Obviously, these models should accurately represent the physical phenomenon of PD activities [1]. Computational models based on equivalent circuits are simple and flexible models which have been previously used for voids as a basic capacitive model (introduced by Gemant and Philippoff in 1932 [1] and even nowadays still in use [2]) and also as a comprehensive model [3].…”