Cable model parameters

Figure 6.234 Cable models with concentrated and differential cable parameters.

The data for cable impedance and admittance calculation using the EMTP are shown in List 4.1. Table 4.3 lists the calculated cable parameters of the XLPE cables. The parameter of the positive sequence is employed for the steady-state voltage simulation. If the cable parameters are provided by the cable manufacturer, parameter calculation by cable constants or cable parameters is not required. The model parameters are obtained from the cable parameters and length as shown in Table 4.4. 

In summary, the loss data obtained on triplex cables showed that for sufficiently large r, the loss was characterized by a single parameter, tq, within the framework of the transformer model and that for small r, the loss saturated at... 

Section 2 explains the model-based approach for localization of cable faults. Section 3 describes the modeling of the transmission line. In Section 4 the parameter extraction using global optimization techniques is described. Section 5 gives the results and analysis. Section 6 gives the conclusion. 

The algorithm for parameter extraction is desca-ibed in Fig. 2. The aim is to calculate the input impedance of the cable system. During the fitting procedure, the calculated input impedance of the eable system is compared with the measured input impedance of the cable system and the input parameter of ABCD model are optimized by DE to find the global... 

In this chapter, the modeling procedures of power line channel have been presented. The deterministic method uses basic network parameters to derive a transfer function of the channel. The investigated deterministic models were determined from an indoor PLC channel. They are specifically topology dependent. For separate network channels, only the cable parameters, the load impedances and the topology of the network are absolutely needed. The LV network is considered as an M nodes and N branches, which is subdivided into several cascaded two-port of small networks. The transfer function of the channel is later obtained by combining easily the T-matrices of the cascades sub networks. The position of notches in frequency response depends on the length of the branched lines. The increase in branched line length tends to limit the available bandwidth in LV channel, but the... 

Figure 4.11. Two lumped-parameter circuit models for studying the effects of ac electrode polarization in microelectrode systems. simulated biological signal source Cj,Q, contact or source capacitances Cp, electrode polarization capacitance = /(co) shunt capacitance of electrode to electrolyte and reference electrode C, cable leakage capacitance and input capacitance to amplifier system ...

The thermal penetration of the cable material was described by the model for Thermally Induced Electrical Failure (THIEF) implemented in FDS. The THIEF model predicts the temperature of the inner cable jacket under the assumption that the cable is a homogeneous cylinder with one-dimensional heat transfer. The thermal properties—conductivity, specific heat, and density—of the assumed cable are independent of the temperature. In reality, both the thermal conductivity and the specific heat of polymers are temperature-dependent. In the analysis, conductivity, specific heat, density, and the depth of the cable insolation were considered as uncertain parameters with relevant influence (see Table 1). 

For a steady-state analysis, a cable can be expressed by a single or a cascaded n-equivalent circuit instead of a distributed parameter line. In the EMTP, even if a cable is represented by a constant-parameter line model (Dommel s line model) or a frequency-dependent line model (Semiyen s or Marti s line model), the distributed parameter line is internally converted into a n-equivalent circuit and is passed to a steady-state analysis routine. 

Because any EMTP-type simulation tool is based on circuit theory, the formulas and values explained in the previous section are adopted. If the distributed-parameter nature of a horizontal or vertical electrode is to be taken into account, a model circuit such as that in Figure 7.9 can be used [22,24]. The electrode is represented by an underground cable composed of a core conductor (electrode) and an artificial insulator. This makes it possible to evaluate the series impedance and the capacitance of the electrode by a subroutine called Cable Constants of the EMTP [35,36-37]. Then, the equivalent capacitance in Figure 7.9b is defined as... 

In a simulation of an induced voltage to an overhead control cable from a counterpoise, the control cable and the counterpoise are represented as a distributed-parameter line in the EMTP [35, 36-37]. The parameters of the line models are evaluated by the EMTP Cable Parameters (CP) [37]. First, the model system is evaluated as an overhead line system by the CP with a negative sign of the depth of the counterpoise. Initially, the input data, the CP gives the self-impedance/admittance of the overhead cable and the mutual impedance to the counterpoise. Then, the self-impedance/-admittance of the counterpoise is calculated as an underground cable. Finally, the self-impedance/admittance of the counterpoise in the first calculation is replaced by those in the second. 

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