Numerical modelling on partial discharge in HVDC XLPE cable

Abstract

PurposeHigh voltage direct current (HVDC) cable is an important part in the electric power transmission and distribution systems. However, very little research has been carried out on partial discharge under direct current (DC) conditions. Niemeyer’s model has been widely used under alternating current (AC) conditions. This paper aims to intend to modify the Niemeyer’s model considering both electric field and charge dynamics under DC conditions, and therefore proposes a numerical model describing partial discharge characteristics in HVDC cable. Design/methodology/approachThis paper intends to understand partial discharge characteristics under DC conditions through numerical modelling. Niemeyer’s model that has been widely used under AC conditions has been modified, taking both electric field and charge dynamics under DC conditions into consideration. The effects of loading level or current through the conductor, cavity location and material properties on partial discharges have also been studied. FindingsElectrical conductivity is important in determining the characteristics of partial discharge under DC conditions and discharges tend to happen in short when the cavity field exceeds the inception level under the parameter values studied in the paper. Research limitations/implicationsBuilding the numerical model is the purpose of the paper, and there is lack in experiment and the comparison between the simulation results and experiment. Practical implicationsThe proposed model provides the numerical model describing partial discharge in HVDC cable and helps understand the partial discharge mechanism under DC voltage. Originality/valueTo the best of the author’s knowledge, this paper is a very early research on the numerical modelling work on partial discharge under DC voltage.

Finite‐element‐analysis models for numerical simulation of partial discharges in spherical cavities within solid dielectrics: a review and a novel method

“…The charges left on the surface of the cavity due to the previous PD may decay in time through recombination, diffusion, and conduction. Under AC voltage, recombination is the dominant process [43]. In analytical‐based models [27], the surface charge decay rate is usually modelled as an exponential decay function, exp(− t/τ ins ), where t (s) is the time elapsed since the last PD and τ ins (s) is the material time constant that depends on the void surface conductivity.…”

“…In [43], an EC FEA model was implemented for PD simulations under DC conditions and was applied for a case of study in a HV DC XLPE cable. Surface charge decay due to charge recombination by charge propagation on the cavity wall was neglected because, at DC voltage, the electric field due to the surface charge is always against the applied electric field, there is no polarity change.…”

Computer Simulation of Partial Discharges in Voids inside Epoxy Resins Using Three-Capacitance and Analytical Models

“…Through a mathematical procedure, the minimum theoretical discharge initiation voltage can be determined, however, as PD will not initiate at this voltage, this value should be increased in order to promote the PD appearance during laboratory tests. In [68], the analytical approach is used for determining the discharge characteristics at DC voltage and it was found that for this case the electrical conductivity plays a fundamental role in the inception voltage, repetition rate and discharge magnitudes, however there is not experimental validation.…”

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

“…Therefore, it seems that the surface charge decay through insulator volume becomes the predominant way. He et al held that the recovery of cavity field after a discharge is only attributed to the charge decay through volume conduction, and constructed a PD simulation model under DC voltage [85]. In our previous research, surface charge dynamic distributions produced by DC PDs were measured [12].…”