Cable parameters

In this procedure, the cable is considered simply as a concentrated capacitance and inductance according to its length. With this simplification, however, things are at the safe side each time. The manufacturers may be asked for the cable parameters. As a rule of thumb 200 nF/km and 1 mH/km are usually adequate. In practice, real cable parameters are generally lower than recommended values. 

Increasing work in the intrinsically safe fieldbus domain has raised problems which are closely related to the so-called cable parameters. The problems ... 

Figure 6.234 Cable models with concentrated and differential cable parameters.

Now we have seen that the burst action is constant for a particular wire material and diameter that the shape of the current-time trace is not a factor in achieving burst that the current-time trace is determined by the fire set and cable parameters that as long as we get burst, and as long as that burst current is sufficiently above threshold, we will detonate the initial pressing. To emphasize this. Figure 25.11 shows current traces and burst points that fired detonators from a wide variety of fireset/cable values. 

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... 

Table A. 2 in lEC 60079-11 for cable parameters may be referred to. Special calculations and considerations are applied for system analysis because of cable faults—especially when multicore cables (see lEC 60079-14 for type A and B cables in connection with multicore cables) are used in the installations [33]. Other important issues here are that (1) voltage drop across the resistor under normal operating conditions has to be taken into account in the design so that there is sufficient voltage at the field device and (2) Zener barriers are properly earthed as shown because without an IS earth they are not safe. To obtain independence from...

Cable constants Ov erhead/underground cable parameters Fiequency, configuration. 

Overhead/underground cable parameters distributed Y, snaking Transformer parameters Transformer parameters Saturation characteristics Hysteresis characteristics (type-96J Equivalent circuit... 

Ametani, A. 1994. Cable Parameters Rule Book. Portiand, OR BPA. 

If the cable impedance and admittance per unit length are provided by the cable manufacturer, the data of the n-equivalent circuit can be easily calculated with the cable length. The cable impedance and admittance can be calculated by cable constants or cable parameters installed in the EMTP using the physical parameters of the cable. The parameters shown in Table 4.2 are generally provided by the manufacturer. 

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 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. 

Schelkunoff s impedance assumes that a conductor is circular or cylindrical. In reality, many conductors exist withcross sections are not circular or cylindrical. The internal impedance of a conductor with an arbitrary cross section was derived in Reference 19, which has been implemented in the EMTP cable parameters program [20]. 

CABLE PARAMETERS Overhead/underground cable Frequency, configuration. 

The data for the cable impedance and admittance calculation for EMTP is shown in List 4.1. Table 4.3 shows calculated cable parameters of fhe XLPE... 

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