CEE Relays Ltd

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DAPPER Study Module
DAPPER is an integrated set of modules for three-phase power system design and analysis including rigorous load flow and voltage drop calculations, impact motor starting, traditional fault analysis, demand and design load analysis, feeder, raceway and transformer sizing, and panel, MCC, and switchboard schedule specification.

A downloadable version of the DAPPER brochure is available in PDF format via a link at the bottom of this page. 

For short-circuit studies to IEC and ANSI standards, consider the following optional modules:
IEC 60909
IEC 61363
A_Fault (uses ANSI standard)
PTW Load Flow Study screenshot
  • Generate better designs by comparing alternatives quickly. 
  • Improve accuracy with DAPPER's rigorous solution methods. 
  • Save time by sharing a common project database and interface with other PTW modules. 
  • Improve consistency with standard design libraries. 
  • Design safer systems by comparing calculations with short circuit and continuous ratings. 
  • Communicate designs effectively with presentation quality graphics, reports, and equipment schedules.
Load Flow and Volt Drop
With DAPPER, users can calculate the voltage drop on each feeder and transformer branch, voltage on each bus, projected power flow, and losses in the power system. 
This program may be used for conventional voltage drop analysis, loss analysis, power factor studies, capacitor placement, long-line charging effects, impact loading for motor starting studies, generator sizing, and for cogeneration analysis. With DAPPER, a single load flow program models looped and radial power systems. Double precision sparse matrix current injection solutions are used for faster, more accurate, convergence. This allows for better modeling of ill-conditioned systems. 
  • Models radial, looped, and multiple independent systems. 
  • Models utility and generator equivalent impedance calculated from short circuit duty. 
  • Models up to 500 utilities/swing bus generators. 
  • Models up to 1500 regulated and unregulated co-generators. 
  • User definable per unit driving voltage at each utility and swing bus generator. 
  • Models transformer primary and secondary taps and off nominal rated voltages. 
  • Full transmission line modeling with built in line parameter calculators. 
  • Models any combination of motor and non-motor loads with global and/or local load factors. 
  • Models any combination of constant kVA, constant impedance and constant current loads. 
  • Reports bus voltage, voltage angle, and voltage drop at each bus. 
  • Reports branch voltage drop, power flow in kW, kVAR, kVA, Amps and power factor. 
  • Reports branch loss in kW, kVAR, kVA, and total system losses. 
  • User definable report criteria for bus and branch voltage drops. 
  • Percentage voltage drops. 
  • Double precision calculations improve solution accuracy. 
  • Rapid solution convergence. 
  • Suitable for impact motor starting, capacitor placement and power factor studies. 
  • Load flow results validated to match with benchmark calculations and IEEE examples.
Comprehensive Fault Analysis
The DAPPER Comprehensive Fault Analysis program provides a network solution of three-phase, phase-earth, phase-phase, and phase-phase-earth fault currents; RMS momentary fault currents; asymmetrical fault duties at three, five, and eight cycles; the positive, negative, and zero sequence impedance values between each fault location, and contributions from utilities, generators, and motors. At each fault location, the direction, X/R, and magnitude of fault currents are reported, thus providing a clear view of the conditions that exist during the fault. 
  • Symmetrical and Asymmetrical values reported at 1/2, 3, 5, and 8 cycles. 
  • Asymmetrical values reported at user selected fault time. 
  • Asymmetrical values reported as peak or RMS values. 
  • Models two-winding and three-winding transformer taps, phase shift, and off-nominal rated voltages. 
  • Asymmetrical exponential DC decay is based on X/R of each contribution. 
  • Reports Thevenin equivalent impedance and X/R at the faulted bus. 
  • Detailed and summary reporting options. 
  • Reports bus voltages and branch flows throughout the system for each faulted bus. 
  • Reports phase or sequence current and voltage. 
  • Reports  earth return current for phase-to-phase-to-earth faults. 
  • Models transformer and generator neutral earthing impedances.
Comprehensive Fault Analysis Demo:
Hover your cursor over the image below to see how DAPPER re-calculates the fault level on a bus-bar with parallel feeders under different operating conditions:
This simple example uses the Scenario Manager built into PTW to consider a system under two different operating scenarios.  The scenarios can also be used to produce reports, like the table below.  PTW can model many different scenarios for your project; this is an excellent way to predict how your network will behave under "best-case" and "worst-case" conditions, or where your load demands are constantly changing. 
Demand Load Analysis
  • Reports Connected, Demand, and Design loads. 
  • All load calculations account for individual load power factors. 
  • Automatically creates input load data for Load Flow and Voltage Drop Studies. 
  • Automatically creates loads for sizing feeders and transformers. 
  • System demand loads calculated using methods recognised by the NEC. 
  • Automatically tracks largest motor fed by each bus to meet NEC requirements. 
  • Automatic compliance with NEC and local codes for multi-level load diversity. 
  • Sensitivity studies, future load growth studies and load diversity studies by scaling load factors globally. 
  • "What if" analysis of loading conditions, for example light loading versus normal loading, or winter versus summer loading. 
  • Meet utility company requirements for providing a load summary by load type for connected, demand, and design loads at each utility bus. 
  • Generate sufficient information for sizing feeders, transformers, and other elements of the power system.
Feeder and Transformer Sizing
DAPPER will size feeder cables, earth conductors, raceways, bus ducts, duct banks and transformers throughout the power system to the load requirements calculated by the Demand Load Analysis program. Feeders are selected to meet user-defined criteria for conductor material, voltage level, insulation type, and environmental conditions. Transformer primary and secondary feeders are sized to the transformer full load as specified by the user. Feeders and transformers may be included, excluded or evaluated in the sizing study. 
  • AWG, Bus Duct, ACSR, or metric sizes may be used. 
  • Feeders and transformers with "Do Not Size" are evaluated for capacity. 
  • Feeder libraries permit user to include metric sizes and current-carrying capacity. 
  • Transformers can be sized to Demand or Design load. 
  • Sizing to the IEE wiring regulations is available
Has your power system changed substantially since the model was created?  Or perhaps you are concerned that your equipment may not be properly rated to withstand the calculated fault levels?  If so, consider the Equipment Evaluation module to check the ratings of all equipment in your system. 
Load Schedules
The DAPPER Load Schedule module provides detailed documentation of load fed through Panels, Motor Control Centres (MCCs) and Switchboards. Input is simplified through the use of libraries and copy and paste functions. The schedules can be displayed, printed, and exported in a variety of different formats. 
  • Schedules are automatically updated with available short circuit values and sub-feed totals. 
  • Switchboard schedules are automatically generated from connected branch loads. 
  • MCC schedules can reference a default design library for automatic selection of feeder and raceway sizes, or the complete cable library for more detailed specification.
A downloadable version of the DAPPER brochure is available here.
PDF 1.3Mb