NEPLAN Network Reduction

This module is designed to reduce the size of a network model by replacing sets of buses and their connected elements (lines, transformers, etc.) with a smaller but exact, numerically equivalent network. For a properly chosen set of buses, this equivalent network will have fewer buses and branches than the original, yet still provide the correct response to faults or load flow calculations in the unreduced portion.

The network can be reduced for

• symmetrical or asymmetrical short circuit calculations according to IEC60909, ANSI/IEEE or superposition method and
• load flow calculation

The reduced network gives the same short circuit or load flow results as the original network. Giving the nodes to be reduced, the program determines the boundary nodes automatically.

Given any network for short circuit or load flow calculation and the nodes to be reduced, boundary nodes are automatically determined. Functions to select a complete network area to be reduced are available.

The reduced network will be represented by shunt and series equivalents, as well as equivalent infeeds. Depending on the type of network reduction, shunt and series equivalents consist of data for the positive, negative and zero system. For load flow network reduction boundary injections and boundary generators are calculated.

Reference: NEPLAN 

NEPLAN Overhead Line / Cable Parameter Calculation

This module allows the calculation of mutual impedances and capacitances in the positive and negative-sequence systems by entering the information on the conductors characteristics and configuration. If the coupling impedances and the line data are known, they can be entered directly in the line-coupling and line data dialogues.

General Characteristics

• Circuit and coupling parameters of the overhead lines are computed from the conductor configuration
• Overhead lines with up to 6 3-phase systems and 3 earth wires can be computed
• Each system can have symmetrical or asymmetrical structure: any phase(s) can be omitted
• Earthing of 3-phase systems is considered
• Unrestricted number of overhead lines can be entered
• Handling of parallel, galvanically connected systems
• Consideration of system characteristics such as segmentation, line-twisting, slacking, etc.
• Parameters and conductor configuration are saved in an SQL database

Line coupling is considered by the Short Circuit Calculation, the Distance Protection Module and for asymmetrical Load Flow.

Reference: NEPLAN 

NEPLAN Arc Flash Calculation

Arc Flash Calculation is completely integrated and based on NEPLAN® short circuit and selectivity analysis modules. It calculates the incident energy for reduced and unreduced arcing current and in function of the working distance and it automatically determines the Arcing Fault Clearing Time. It also determines individual arcing current contributions.

 General Characteristics

• Calculation methods: IEEE 1584 & NFPA 70E
• New standards: IEEE for DC systems & ISSA (International Social Security Association)
• Supports ANSI/IEEE and IEC short circuit calculation for symmetrical and unsymmetrical fault
• Individual parameter setting to determine the incident energy
• Automatically assign hazard category

Arc Flash Calculation module gives the possibility of multiple arc flash simulations just in one run.

Results

Upon calculation results are automatically displayed on the single line diagram while their content and graphical information can be customized. Display of results is node oriented and can be inserted at any node or element. Result evaluation and processing is easier due to visualization functions:

• Overloaded pieces of equipment (current transformers, voltage transformers, circuit-breakers, etc.) are highlighted
• Output list is sorted by voltage levels. Arcing current, incidence energy, arcing fault clearing time, Personal Protective Equipment (PPE) category and all appropriate results are displayed
• Table interface with MS-Excel
• Workplace safety: a flexible Label can be printed out by including the hazard classes and all required results

Reference: NEPLAN   

NEPLAN Load Flow / Contingency Analysis

Load flow

This module performs Load Flow studies for 3-, 2- and 1-phase AC and DC systems for meshed, looped and radial networks from HV to LV. It includes disperse generation models such as wind power, photovoltaic, small hydro, geothermic, etc. and provides a wide variety of calculation options to address specific applications. Modelling can be particularly defined with NEPLAN® C/C++ API.

General Characteristics

• Computation methods: Current Iteration, Newton Raphson, Extended Newton Raphson, Voltage Drop (per-phase), DC load flow
• Voltage and flow control with phase-shifting transformers
• HVDC, PWM and FACTS devices, like SVC, STATCOM, TCSC, UPFC
• DC-Batteries, DC-Fuel cells, DC-Voltage source, DC-Photovoltaic panels
• Node types: slack, PQ, PV, PC, SC, PI, IC with intuitive assignment. More than one slack node possible
• Power interchange between area / zones (area interchange control) and distributed slack node
• Predefined and user defined scaling factors for fast load and generation variations
• Measurement data import and load balancing
• Calculation of loss sensitivities (PDTF-factors)
• Powerful convergence control with initialization file input / output
• Limit check and appropriate automatic conversion of the node type

Results

Upon calculation results are automatically displayed on the single line diagram while their content and graphical information can be customized. Result evaluation and processing is easier due to visualization functions:

• Overloaded elements or nodes with voltages outside predefined limits are highlighted
• Line thickness corresponds to element loading
• Table output: for the whole network, individually for each area / zone. Listing of power flows between areas/zones, overloaded elements, sorting function, selective output
• Results can be saved in a text file (ASCII)
• Table interface with MS-Excel

Contingency Analysis

This module allows the user to define all elements and nodes to be disconnected during the contingency analysis. In single mode outage nodes or elements are disconnected one by one and the load flow is calculated. Common mode outages can also be defined to disconnect several nodes and/or several elements at the same time.
Results demonstrate the outaged elements, the value of the variable violating limits and the divergence of this value from the base case in %. The outages are listed in order of decreasing number of voltage and current violations.

Reference: NEPLAN  

NEPLAN Short Circuit Analysis

This module performs Short Circuit Analysis on 3-phase, 2-phase and 1-phase AC and DC systems, for single-, two- (with and without earth connection) and three-phase faults. It provides the option of computing line faults or even user-defined fault types such as double earth faults, faults between two voltage levels, conductor opening, etc.

General Characteristics

• Standards IEC909 1998, IEC60909 2001, IEC60909 2016, ANSI/IEEE C37.10/C37.13, G74 Engineering Recommendation
• IEC 61363-1 for off-shore/ship plants
• IEC 61660 for DC networks
• Superposition method with consideration of prefault voltages from a load flow
• Computable fault current types: initial symmetrical short-circuit current and power, peak, breaking, steady state, thermal and asymmetrical breaking current, plus DC component
• Computation of minimum/maximum short-circuit current
• Accurate model for transformer earthing connection
• Earthing system for common earthing of any number of transformers, generators, etc.
• Petersen coil tuning in resonance earthed networks
• Current limiting due to circuit breakers and MOV
• Calculation of relay tripping times, e.g. for over current and distance protection
• Contribution of adjustable frequency drives and static converter to short-circuit currents

Line Coupling

Short Circuit Analysis module allows for mutual impedances and capacitances in the positive and negative-sequence systems which are computed from the conductor configuration. Overhead lines with up to 6 3-phase systems and 3 earth wires can be computed (earthing of 3-phase systems considered) while unrestricted number of overhead lines can be entered. Finally, parameters and conductor configuration are saved.

Results

Upon calculation results are automatically displayed on the single line diagram while their content and graphical information can be customized. Display of results is node oriented and can be inserted at any node or element. Result evaluation and processing is easier due to visualization functions:

• Overloaded pieces of equipment (current transformers, voltage transformers, circuit-breakers, etc.) are highlighted
• Output list is sorted by voltage levels. Short-circuit impedance and all computable fault currents are displayed as phase values or as symmetrical components
• Results can be saved in a result file and SQL database

Reference: NEPLAN