Load Flow Analyzer - DC
(DC LFA)
RAILSIM Load Flow Analyzer
(LFA) has been developed for the comprehensive and flexible
modeling of any electrical network of any complexity, RAILSIM LFA
analyzes system electrical capacities, power demand, power costs,
effects of regenerative braking and many other electric network
issues. RAILSIM LFA analyzes DC (direct current) electrical
networks. For AC (alternating current) network analysis, the
AC LFA module is required.
RAILSIM LFA lets you
graphically monitor up to 3 independent locations
and variables during the solution process.
RAILSIM LFA analyzes
the loads, potentials and regenerative braking receptivity on a given
system supplying power for the operation of electrified rail under
prescribed operating conditions. The base LFA model is built and
maintained in RAILSIM Editor and includes:
- Substations
- Feeders and Returns,
- Power Costs
LFA uses the defined
model, and train operations and unconstrained electrical load
requirements derived from RAILSIM TPC, as well as pertinent
user-defined parameters to understand the physical plant of the
electrical network. RAILSIM LFA also accommodates user-specified
train operational information and substation and feeder schedules.
With this information, LFA simulates the electric load throughout the
network, providing results such as total power consumption, peak power
loads, substation loads, system losses and train voltages. RAILSIM LFA
has these features/capabilities:
- Support for rail
networks of any complexity,
- Mixed fleet
operations (trains with different characteristics and consists),
including none, some or all with regenerative catenary capability,
- Deterministic
(non-variable) and stochastic (variable) train operation/headways,
- Support for
headway-based inputs with identical train types,
- Support for
unlimited variation in train types, train lengths and schedules,
- Connections between
different tracks (jumper wires),
- Cross track
connections between running rails,
- Conductor gaps
(bridgeable or unbridgeable by the train) in overhead or running
rails,
- Overhead trolley
wire isolation switch status (on or off at given time duration),
- Substation outages
for specified time durations,
- Positive feeder or
negative feeder outages for specified time durations,
- Static loads on or
off at given time duration to reflect yard or shop loads, including
import capability for static load profiles that vary by time of day,
- Rail to earth
leakage resistance included in the model to generate rail potential
profiles, to facilitate further analysis of touch voltages and stray
currents,
- Support for single
rail return for traction current at specified locations,
- Different size of
overhead conductors (trolley wires and contact wires) in different
sections,
- Different sizes of
running rails (and different size/composition of third rail
sections) in different sections,
- Power, energy and
cost analysis for each power zone that supplies a group of traction
substations,
- Receptivity of
regenerated power (for each train simulated and for the overall
system), and
- Energy saving due to
regenerative braking (for each train simulated and for the overall
system).
Substation characteristics
and associated feeders are easy to define in RAILSIM LFA.
RAILSIM LFA supports
custom specification of:
- Positive and
Negative Feeder Conductor Locations
- Track Circuit
Section Boundaries (Supply Conductor Gaps)
- Overhead Line/Track
Resistance Change Points
- Generic Load and
Resistance Point Locations
- Track (Supply
Conductor) Isolation Switches
- Track Leakage
Resistance Change Points
- Supply/Return
Jumpers
- Train Volume
Monitoring by Location
- Energy storage
devices, such as flywheels and storage batteries, and substation
diode drainage
- Substation Loads
- Power Cost Profiles,
which can include Peak Power Constraints of three types:
- Instantaneous
- Fixed Interval
- Sliding Interval
Electrical network
attributes are defined only at locations where they change,
based on the chainage/stationing system.
LFA Typical Output
Text and graphical
output is easily generated in RAILSIM Report Generator. The Load Flow
Text Report Wizard supports the simultaneous specification of detailed
and summary reports, including:
- Train reports with
time and distance-based electrical demand
- Voltage at train
pantograph or third rail shoe
- Substation loads and
voltages
- System electricity
costs predictions, including energy consumption and a variety of
demand-based rate structures
The Load Flow Plot
Wizard permits simultaneous specification of up to 11 different plots
per selected analysis. Typical output includes:
- Detailed train
reports with time and distance-based electrical demand,
- Voltage and current
at train pantograph or third rail shoe,
- Substation loads and
voltages,
- Time over current
("current limit") reports that highlight potential breaker trip
occurrences,
- Low voltage report,
highlighting all occurrences of trains experiencing less than
desired voltage at the third rail shoe or pantograph,
- Prediction of system electricity
costs, including energy consumption and a variety of demand-based
rate structures (which can vary within the simulated territory by
substation utility feed).
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