Power Cable Model Research Articles

HTS Power Cable Model Component Development for PSCAD/EMTDC Considering Conducting and Shield Layers

The resistance of conventional power cables is not changed a lot by fault current condition. But HTS power cable has some different properties. The impedance of superconductor is changed due to the magnitude of current, temperature, and magnetic field. Before applying the HTS power cable to the real utility, the system needs to be analysed using certain simulation tools. Even though PSCAD/EMTDC is one of the most useful simulation tools, it does not provide the component of HTS power cable which has the same impedance characteristic of real HTS power cable. The authors developed the component of HTS power cable whose electrical properties were obtained under DC current condition through previous research work. The performances of HTS cable component for PSCAD/EMTDC have been improved under AC current condition in this paper.

Characteristic analysis of 154 kV HTS power cable under fault conditions using PSCAD/EMTDC

This paper deals with the characteristic analysis of 154 kV HTS power cable system under fault conditions using PSCAD/EMTDC (Power System Computer Aided Design/Electromagnetic Transients including DC). Before applying the HTS power cable to the real utility, the system needs to be analyzed using certain simulation tools. The resistance of conventional power cables is not changed by fault current. But HTS power cable has some different properties. The impedance of superconductor is dramatically changed along with the current over the critical value, temperature, and magnetic field. PSCAD/EMTDC does not provide the HTS power cable model which includes the same electrical characteristics of real HTS power cable. In order to develop the EMTDC model component of 154 kV class HTS power cable, the authors have manufactured a 1/58 HTS model power cable and experimented under several types of fault conditions. The measured characteristics of the model cable, resistance and temperature variation, were used to develop the HTS power cable model component in EMTDC. Using this model component, HTS power cable system was analyzed under the fault conditions. The simulation results of fault current, temperature and resistance variation of HTS power cable are described in detail, and how to apply the characteristics of HTS power cable in the simulation tool is also discussed in order to demonstrate the effectiveness of the proposed model component of 154 kV class HTS power cable.

Skin effect and dielectric loss models of power cables

In power electronics applications, power cables spread paths of conducted disturbances throughout the system. This paper proposes a high frequency modeling method for power cables that takes into account phenomena which appear when the switching frequency of the static converter increases, such as skin effects, proximity effects and dielectric losses. The proposed power cable models are obtained by the series association of n identical RLCG basic cells. The skin and proximity effects are represented as the impedance of an R-L ladder and the dielectric losses as the admittance of an R-C ladder. The proposed method was successfully applied to a three-wire unshielded cable and extended to a four-wire shielded cable.

Critical Current, Critical Temperature and Magnetic Field Based EMTDC Model Component for HTS Power Cable

Before applying the high temperature superconducting (HTS) power cable to real utility network, system analysis should be performed using simulation tools. For the practical use of HTS devices in electrical power system, prior simulation analysis is very important. PSCAD/EMTDC simulation is one of the most popular and useful analysis tools for electrical power system. Unfortunately the model component for HTS power cable is not provided in the PSCAD/EMTDC simulation tool. In this paper, EMTDC model component for HTS power cable has been developed considering critical current, critical temperature, magnetic field, and recovery time constant which depend on the sorts of HTS wire. The numerical model of HTS power cable in the PSCAD/EMTDC was designed by using the real experimental data obtained from a real HTS 1G wire test. The utility application analysis of HTS power cable was also performed using the model component developed. The component for HTS power cable could be variously used when the power system includes HTS power cable, especially it will be readily analyzed by the PSCAD/EMTDC in order to obtain the data for the level of fault current, power flow, and power losses, and so on.

A novel real-time simulation method of the utility power network including the HTS power cable

High temperature superconducting (HTS) power cable, characterized by its large transmission capacity in compact dimension, small transmission loss, no leakage of electro-magnetic field to the outside of the cable and small impedance. HTS technology can be useful to overcome this program. Recently, according to the advanced HTS technology, the power application is being researched well. However, several kinds of simulation, which analyze the transient phenomena of HTS power cable itself, are basically required before installation according as the impedance level of HTS power cable is dramatically changed in case of quench at fault condition.In this paper, the authors propose RTDS simulation method, which puts a real miniaturized HTS power cable into the imaginary utility power grid system simulated in RTDS. For the simulation analysis, the miniaturized HTS power cable was actually manufactured, and the transient phenomenon of the miniaturized HTS power cable model core was analyzed in the simulated utility power grid.

Transient tolerance analysis of power cables thermal dynamic by interval mathematic

The safeguard of power equipments is assuming a major role in the deregulated electricity market, where a malfunctioning power system could be responsible for serious damages to a large number of system operators having access to the shared energy resource. In this context thermal monitoring of power cables represents a key issue in evaluating the risks associated with a given load management policy especially during emergency conditions. In particular this demands for reliable assessment models that should be able to predict the transient thermal behaviour when the load exceeds the nameplate value. In this connection the application of both simplified and detailed power cable thermal models is often complicated by the presence of uncertainties affecting the tolerances of the input data. The effect of these uncertainties could influence the final solution to a considerable extent. A comprehensive tolerance analysis is therefore required in order to incorporate the effect of data uncertainties into the thermal modelling process. To address this problem, in the paper the employment of interval mathematic is proposed. Several numerical results are presented and discussed in order to assess the effectiveness of the proposed methodology which offer a rough qualitative insight of the solution in a very short time, comparable to the time required for a deterministic numerical simulation.

The current test results for two models of HTS cables on CASAT project

Two models of HTS power cables were made and tested. The cable of Nordic Superconductor Technology (NST, Denmark) tape has 4 layers and length of 1 m, and the cable of Vacuumschmelzc (VAC, Germany) tape has 6 layers and length of 5 m. The test of the cables was performed at currents up to 6 kA (AC) and 10 kA (DC). Temperature was 78 K, uniform along the models' length. The critical current was more than 10 kA for 6 layers cable at 78 K. Main attention was paid for current distribution study in the cable models. Measurements of the current distribution between layers showed uniform current distribution and high level of superconducting tapes current currying capacity utilization. The comparison of the experimental and theoretical results showed reasonable coincidence. The tests will be continued at a various temperatures up to 100 K.

AC losses in circular arrangements of parallel superconducting tapes

The DC and AC properties of superconducting tapes connected in parallel and arranged in a single closed layer on two tubes (corresponding to power cable conductor models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e., the critical currents of the two arrangements, scale with the number of tapes and hence appear to be independent of the diameter. However, the AC loss per tape (for a given current per tape) appears to decrease with increasing diameter of the circular arrangement. Compared to a model for the AC loss in a continuous superconducting layer (Monoblock model) the measured values are about half an order of magnitude higher than expected for the small diameter arrangement. When compared to the AC loss calculated for N individual superconducting tapes using a well known model (Norris elliptical) the difference is slightly smaller.

A simplified analytical model of power cable for the calculation of transient voltage and current of faulted power systems

In this paper, a simplified cable model for waveform analysis of fault voltage and current is proposed. This model is based on the concept of equivalence earth conductivity to take into account the effects of live parameter frequency dependency and metal sheath/ground circuits.