TACLINK®  is a nodal network analysis program that is optimized for grounding analyses. We based TACLINK® on standard nodal network analysis procedures and  have tested it extensively. Nodal analysis results can be verified easily because, for any calculation, the vectorial sum of the currents flowing into and out of a node must be zero. Other results, such as node potentials, must fit the currents flowing in the network elements and can therefore also be verified.

With TACLINK® we have enhanced the basic nodal network analysis algorithm in several ways:

• The network may contain transformers. These are represented as perfect two winding transformers with a specified primary to secondary ratio. The ratio may be complex so that a phase shift can be introduced if desired. Actual lossy transformers can be simulated by adding impedances to represent the magnetizing and/or series impedance of the transformer. Three phase transformers with complex winding configurations such as Y-Y-delta can be accurately modeled using sets of two-winding transformers connected as required.

• Portions of the network may be entered in impedance and/or admittance matrix form. This enables modeling of coupled circuits with all the mutual coupling impedances correctly represented.

• A number of complex elements can be added to the networks using simplified data entry. For example:

• Three-phase power sources can be added using a data format where only the line-to-line voltage, source impedance, phase angle and node connections are required. The source impedance can be in symmetrical components in ohms or p.u. on a given base MVA and kV or as self and mutual impedance parameters. The program develops the required current sources and impedances from the input data.

• Various transformer connections can also be added in a simplified form. For example, a Y-delta or Y-Y-delta connected transformer can be added by specifying the primary, secondary [and tertiary] voltage, size in MVA, percent impedance/s and nodes to which it is connected. The program will model the transformer using ideal single-phase transformers and impedances.

• TACLINK® can read a number of pre-defined coupled circuit configurations directly and will calculate the required impedance matrix. Configurations included are:

• Any number of parallel conductors. Only the height and spacing of the conductors and their individual sizes and types need be entered. TACLINK® uses a database of conductor parameters that covers the most widely used copper and ACSR conductors. Other types can be added by the user, as required.

• Buried cables with and without ground wires. There can be any number of cables and ground wires. The cables can be single conductor or three conductor. The required input data are the cable core parameters, sheath inside and outside radius, sheath metal type, burial depth and spacing of the cables and ground wires.

• Cross-bonded single conductor cables. TACLINK® will read data for sets of cross-bonded cables and develop the combined impedance matrix for a full sheath rotation.

• Buried pipelines parallel to other conductors can be modeled. TACLINK®  will develop the impedance matrix and include the pipelines as lumped impedance pi -networks. The required input data is the pipe diameter, wall thickness, resistivity and relative permeability of the pipe metal, coating resistance, burial depth and spacing from other conductors.

The present version of TACLINK® is written in ‘C++’ and can be run on an IBM compatible PC having a 32 bit operating system (Windows 95/98/ME/NT4/NT2000). The maximum model size depends on the model configuration as matrix sparsity is exploited. Models with more that 15000 nodes have been analyzed.

We sell TACLINK® for $7,500.00 and will provide one day of training in its use for $1,000.00. The prices are in United States dollars.

We have used the kernel of TACLINK® in other analytical programs to generate complex distribution models, automatically investigate many fault locations in a transmission system and the effect of sequential firing of rated spark gaps.

TACLINK® is described in detail in the user manual that is available for downloading.

Other sample files:

Sample input data file (11k) used to analyze ground fault effects of a large Cogeneration project on an existing Pulp Mill. The Cogeneration project was constructed close to the Pulp Mill and connected to the 138 kV transmission lines that supply power to the Mill.

The calculation will generate a log file (9k) and results file (52k). You need to refer to the user manual to properly understand the data format used.

For more information or to order TACLINK®, please contact us.

CONIND™ (CONduction and INDuction) is a pipeline interference analysis program.

It is based on the work carried out in the 1979 EPRI/AGA study "Mutual Design Considerations for Overhead AC Transmission Lines and Gas Transmission Pipelines". This study presented a series of engineering programs written for the Texas Instruments TI59 programmable calculator. The original calculator programs used sophisticated algorithms, based on accepted methodology and could be used to determine pipeline parameters, self and mutual coupling impedances, electric fields due to currents in power conductors and to do network reduction.

The most recent version of CONIND™, which is written in  ‘C++’, uses algorithms derived directly from the basic equations in the EPRI study. CONIND™ also includes a feature to enable the addition of soil potentials such as would occur if a pipeline passes close to a substation where there is a ground fault.

CONIND™ represents the pipeline/power line model as a series of nodes. The conditions along a segment between any two nodes are constant. The size of the model is only limited by computer memory. The network can have any number of branches such as mitigation wires and pipeline spurs. Each segment of the model can be defined with different soil resistivity, pipe parameters, power line exposure and soil potential. Power line information is entered as x and y co-ordinates related to the pipeline. There can be any number of parallel conductors, each carrying a different vectorial current. Lumped impedances such as ground beds or connections to other pipelines whose impedance is known, can be added at any node.

The program solves the model by iterative passes through it, until stability is achieved. For models without any loops, usually only two or three iterations are required. For models with loops, more iterations may be needed. The Thevenin circuits are then combined at each node to give the node voltage and the currents flowing into and out of each pipe segment are determined. The output results contain Thevenin equivalent circuits at each node and the current flowing into and out of each pipe segment. The Thevenin equivalent circuit at each node gives the node voltage and driving impedance. By selecting a suitable node numbering sequence, the node voltage results can be plotted to obtain a potential profile for a portion of the pipeline.

We have used CONIND™ to model a gas pipeline system with over 600 km of main and branch pipelines. The pipelines have parallel pipe sections and parallel exposure to three 500 kV, six 230 or 287 kV, ten 138 kV and twelve 69 kV transmission lines. The potential profile along the main line and branches was calculated for 32 different power system ground fault conditions. This process was automated to produce a "worst case" profile of the pipeline potentials so that hazardous areas could be identified and mitigative measures implemented by the pipeline owner. We believe this may be the most extensive pipeline electrical coupling study that has ever been carried out.

We sell CONIND™ for $6,500.00 and will provide one day of training in its use for $1,000.00. The prices are in United States dollars.

CONIND™ is described in more detail in the user manual and sample files of a simple analysis problem.

For more information or to order CONIND™, please contact us.