Software modules for electricity network planning


Electrical networks

PSS SINCAL offers a comprehensive range of analysis modules and tools facilitating the planning, design and operation of power systems. Its field of application ranges from short-term to long-term planning tasks, fault analysis, reliability, harmonic response, protection coordination, stability (RMS) and electromagnetic transient (EMT) studies.

PSS SINCAL supports all types of networks from low to the highest voltage levels with balanced and unbalanced network models e.g. four wire systems or transposed systems with the full coupling matrix.

Using the PSS SINCAL program, engineers can simulate future scenarios and thus help avoid costly design errors or misinvestment. It is the ideal tool for simulating smart grids and their effects including linkage to smart meters.
Several analysis modules, such as protection or dynamic simulation, are also ideally suited for training purposes.

(Unbalanced) load flow calculation

Load flow or power flow calculation is the program module for the analysis and optimization of existing networks. Weak point determination is one of the important tasks in network planning. Different algorithms – i.e. Newton-Raphson, current iteration and others – are available for calculating the distribution of currents, voltages and loads in the network, even under difficult circumstances, e.g. when several infeeds, transformer taps and poor supply voltages are involved.

  • PSS SINCAL can handle more than one – isolated – network at the same time.

  • Networks with more than one slack are possible.

  • The power flow type of each generator or infeed can be set individually, e.g. swing bus (slack), PV, PQ or I type. Controllers with operating points and limits can be modeled. A re-dispatch according to user defined limits or power frequency characteristics is selectable.

  • Transfer capacity planning through different network areas /groups is possible.

  • The voltage and power controller can automatically calculate the optimal tap position of transformers or other switched elements like shunts or capacitors based on specified target voltage or power ranges.

  • Voltage and power regulation at a remote node is possible.

  • Master and slave controller function for networks with parallel transformers is available.

  • Different load types can be modeled

  • Load flow can handle phase shifting transformers and fully unbalanced transformers like center-tapped models.

  • Load flow already supports voltage and power dependent shedding of loads or generators (e.g. DC elements like photovoltaic panels)

  • Many other PSS SINCAL modules, such as multiple faults, stability, motor start or protection, use the results of the load flow module as a starting condition.

  • Starting value determination algorithm

  • PSSE load flow calculations can be directly started in the PSSSINCAL user interface if PSSE V32 or V33 is installed and licensed on the computer.

Color-coded evaluations of input data and results in the network graphic and filtering of data in the spreadsheet view is possible e.g. for:

  • Voltage ranges

  • Node overviews

  • Network and sub-network losses

  • Tap settings for transformers

  • Loading of elements

  • Voltage profiles

Graphical evaluation can be done, e.g.:

  • Overloaded system elements

  • Isolated network parts (without a feeding)

  • Contour plots of selected results, such as load flows, load densities and short-circuit levels, in the network diagrams with selected results

  • Customizable annotations

  • Displaying of selected network regions which are of interest (not every element must have a graphical representation)

  • Diagrams (e.g. voltage profile) showing the results for selected paths through the network can be created

  • Unbalanced power flow
    In PSS SINCAL balanced network models can be easily transformed into an unbalanced network model by simply specifying the connected phases and entering single- or two-phase connected network elements (loads, generators, transformers, center-tap transformers, lines, etc.).

Short-circuit calculation

Short-circuit analysis is the method employed for assessing the correct ratings for the network (i.e. the maximum fault currents) and also the correct protection settings (i.e. the minimum fault currents).

Single-phase, two-phase, two-phase-to-ground and three-phase faults can be calculated for individual nodes or whole sub-networks, i.e. it is possible to calculate the short-circuit current distribution in the network for each fault condition. The calculation can be performed in accordance with the standards ANSI C37, IEC 61363-1, VDE 0102, IEC 60909, engineering recommendation G74, and taking into account pre-fault loading. Any possible changes to the standard are incorporated directly and smoothly into the calculation process, since our experts are participating in standards committee meetings. In the case of asymmetrical faults different transformer vector groups are also taken into account, as are the various methods of neutral earthing employed. The short-circuit current rating of bus bars and cables (1-second current) can be checked, too.

Network design and planning tasks for which expected maximum currents are decisive are normally carried out in accordance with the relevant standard. However, if the minimum fault currents need to be determined, the preferred choice is the load flow superposition method, which takes into account the network’s pre-fault loading condition. This is especially the case when the fault current has the same order of magnitude as the load current.

The key values of the short-circuit analysis standards for assessing the fault characteristics (such as Ik“, ip, Ia, Sk“, Uo, Z0/Z1, etc.) and other relevant information are stored in the data base where they are available for further calculations. The calculation reports include fault location-based tables with all contributions and branches viewed together with summaries of results.

  • IEC 60909/VDE 102

  • IEC 61363-1

  • ANSI C37

  • Engineering Recommendation G74

  • Short-circuit analysis considering pre-fault loading conditions

  • Calculation with symmetrical components

  • Arc impedances can be taken into consideration

  • Key values are Ik“ ,ip, Ia, Sk“, Uo, Z0/Z1

  • ip can be calculated optionally according to radial network, meshed network or to the equivalent frequency method

  • Block generators are implemented according to the standards in two different ways (generator and transformer as two separate elements or combined as one element)

  • DC equipment like PV or wind is modeled with the correct contribution, different to normal rotating machines, taking into consideration also the possible disconnection according to the connection rules

  • Neutral grounding

  • Phase shifts in transformers

  • Calculation in selected or all voltage levels at the same time

  • Calculation of all currents in the whole network for a single fault location

  • Calculation of faults at every node in specified voltage levels simultaneously

  • Various reports for all nodes, all fault locations all network levels

  • Color-coded evaluation of network diagrams, e.g. the violation of equipment ratings such as the permissible 1-sec short circuit current rating of lines or bus bars

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