4.1.4.- EFECTO SOBRE COCHINILLAS
4.1.5.- EFECTO SOBRE ÁCAROS FITÓFAGOS
The observation, instrumentation, measurement, and collection of real-world data on the transit system for utilization in the validation effort will necessarily require technical, managerial, and financial support. 21 Managerial and financial support will be provided by the transit property. The preferred source for technical support is also from the transit property but can be provided by the consultant if necessary.
It is recommended that the validation effort occur according to the definition of integrated validation as described in Annex C of IEEE Std 1012-2005 [B28] (with the consultant operating in the role of the development organization, and the transit property operating in the role of integrated IV and V organization). This approach recognizes the possible benefits of, but does not mandate, technical independence between the development organization and the integrated IV and V organization.
IEEE Std 1653.3-2012
IEEE Guide for Rail Transit Traction Power Systems Modeling
Copyright © 2013 IEEE. All rights reserved.26
Annex B
(informative)
Contents of typical report on train operations and wayside network
modeling
The following is a summary description of the contents of a typical simulation report. This guide suggests the following format for reports:
Report cover/title page (including task identification, client, and date of report) Table of Contents
Executive Summary (including overall management-level description of findings and conclusions)
The executive summary should include a brief description stating the purpose of the analysis and the intended outcome (e.g., (a) to define traction power system requirements to serve a new system or to facilitate operation at a higher service level, or (b) to determine service levels that can be met with an existing system). The executive summary should also provide an overview of the conclusions reached via analysis.
Introduction (describing purpose of report and issues/questions addressed)
The introduction should provide a complete description of the process through which the scope of work was developed. If prior reports/analyses dealt with similar issues, they can
be referenced here. Assumptions and Criteria
The underlying data applicable to the modeling effort related to operations levels, failure criteria, etc. To the extent that specific design criteria standards of the transit property are applicable, they should be stated or referenced here. Operations and criteria should include a complete description of the relevant technical parameters and assumptions that have been utilized in modeling and analysis.
Results and Discussion (presentation of technical findings)
This section should include technical description of the output parameters that were developed during the analysis, and their impact on final determinations made under the study.
Conclusions and Recommendations
Conclusions and recommendations should provide a more detailed description of the final recommendations (compared to the description in the Executive Summary).
Appendices (Charts, graphs, tables, input and output data as appropriate)
Appendices should include listing of relevant input data used in analysis (if input data has not otherwise been documented as data of record), or references to relevant previously published or documented items. Output data from simulations and analysis should be reproduced (condensed if and as necessary) to allow for review by the reader
IEEE Std 1653.3-2012
IEEE Guide for Rail Transit Traction Power Systems Modeling
Annex C
(informative)
Detailed input parameter list for dc system analysis
Table C.1 provides a detailed list of input parameters for dc system analysis, including consideration of vehicle performance. Not all of these parameters are necessarily required for any given analysis:
Table C.1—Parameters list for dc system analysis
Item Description of data required Example or comments
1 Plan and profile of the track route, including proposed passenger stations
Starting from passenger stations uses considerable energy; and passenger station locations, as well as grades and curves (speed restrictions), largely dictate the locations of maximum energy use.
Stationing of switch points, platform ends, beginning and ends of curves, etc., and of traction power facilities should be identified.
2 Train voltages:
Maximum tolerated
Maximum under regenerative braking Unloaded voltage of power supply Nominal voltage of power supply (i.e., at
100% load)
Lowest voltage for specified or required tractive effort
Diminished tractive effort (possibly several points)
Lowest allowable operating voltage for propulsion
Undervoltage cutout of vehicle
The list to the left shows, in ord er from highest to lowest, the voltages that are often defined in traction power engineering. Not all voltages are applicable to all transit agencies.
IEEE Std 1653.3-2012
IEEE Guide for Rail Transit Traction Power Systems Modeling
Copyright © 2013 IEEE. All rights reserved.28 Table C.1, continued
3 Rail-to-earth voltages
Max under normal operating conditions Max under defined contingency operation Track leakage resistances are needed to compute this
Touch and step potentials are a safety concern. There are no U.S. standards, but 50 V to 70 V is often cited as a design goal for normal operating conditions, and 70 V to 100 V as a design goal for contingency conditions with substations out of service. IEC 62128 [B23] specifies this potential as a function of time. Refer to 3.2.7.5.
Track leakage resistance varies with the types of track construction and with the weather. The maximum resistance values are used to determine the rail-to-earth voltages. Representative values:
New direct fixation track: 1000 ohms to 1500 ohms – 304.8 track m (1000 track ft)
Aging direct fixation track: 500 ohms to 1000 ohms – 304.8 track m (1000 track ft).
Dirty direct fixation track: 50 ohms to 250 ohms – 304.8 track m (1000 track ft)
Timber tie special track work 250 ohms to 500 ohms – 304.8 track m (1000 track ft)
Any type of wet track - 2 ohms to 10 ohms- 304.8 track m (1000 track ft)
Note that track leakage resistances are often, but
incorrectly, spoken of using terminology such as “X ohms per 1000 track m (ft).” The “per” is improper here
because it suggests that the total resistance increases with track length. A longer length of track will result in lower total resistance, measured from the track section to ground.
4 Locations of traction power facilities Traction power substations
dc: Switching stations (a/k/a circuit breaker house, tie breaker station, paralleling station)
These need to be defined in terms of the stationing of the connection points to the OCS or contact rail and the running rails as well as a cabling distance from the actual TPSS location to the railway.
Often, the objective of the engineer’s work is to determine where traction power facilities need to be placed in terms of electrical performance, or to verify adequate traction power system performance when the locations of the
facilities are determined by available real estate or other factors. This will be an iterative process.
5 Speed limits and signal design At any point on the railroad, the speed limit is the lower
of: (1) any applicable law, as may be the case for street running (2) the capability of the vehicle (3) braking distance considering train control and station stops (4) track limits, especially curves. Minimum end-to-end run time requires making maximum possible speed all along the way, but accelerations due to speed limit changes can have a dramatic effect on total energy consumption.
6 Design headway and consists station dwell
times
7 Vehicle weights See 2.1.
8 Vehicle dimensions, including frontal area and
rotational portion
Train resistance is an important factor in energy use; aerodynamic wind resistance becomes particularly significant at higher speeds.
9 Tractive effort curves A curve showing tractive effort as a function of speed for
the vehicle is necessary to model the train performance. Tractive effort at speeds above initial start will generally be reduced with diminishing voltage, so a family of
curves is used to describe the performance o f the vehicle.
10 Acceleration rates, adhesion data 1.341 m/sec2 (3 mphps) is often specified as the
maximum acceleration rate 11 Braking effort curves, braking rates for friction,
resistive, regenerative, and blended modes
Service braking is often specified as 0.67 m/sec2 (1.5 mphps), with emergency braking of 1.117 m/sec2 to 1.341 m/sec2 (2.5 mphps to 3 mphps).
IEEE Std 1653.3-2012
IEEE Guide for Rail Transit Traction Power Systems Modeling
Table C.1, continued
12 Regenerative braking The use of regenerative braking can return substantial
energy to the line. A net reduction in purchased energy of 10% to 30% is often found when regenerative braking is fully deployed. Shorter headways and more frequent stops result in percentages toward the higher end of the range. In addition to the simple savings in money, regenerative braking will substantially reduce the heat rejected to the
atmosphere, which is of particular value in tunnel operation, as this makes for a far more comfortable environment in underground stations.
Also refer to 3.2.4.
13 Vehicle current or power limits
14 Overall mechanical efficiency Considering tractive effort of the vehicle vs. power in at
the pantograph or contact rail shoe, this is often in the 80% to 85% range.
15 Auxiliary power requirements The vehicle auxiliary power system provides energy to
lights, heating/ventilating/air conditioning, and other systems. These are usually considered “always on” for modeling purposes, and in fact will comprise the vast majority of the load for sub stations feeding yards and shops. 30 kW to 100 kW per car is normal and is generally related to the length of the car. Resistance heating usually draws more power than air conditioning, so in cold climates, the peak load will occur in winter, while in hot climates, the peak load will occur in summer.
16 Traction power schematic diagram, impedances
of traction power system
Tentative ratings of equipment are necessary to commence modeling but are likely to be refined as the design progresses.
For dc substations, the following values are often fou nd: Utility supply at 12.5 kV to 34.5 kV
Rectifier ratings of 0.5 MW to 5 MW (light- and heavy- rail systems; streetcar systems use smaller).
Transformer-rectifier voltage regulation of 4% to 6% Typical values for conductor impedances are given in Annex D.
A return diagram is useful to show where double-rail and single-rail returns are used (if mixed), where isolation in the return circuit is employed (i.e., yard-to-mainline junctions, line-to-line interchanges if applicable)
Lengths and impedances of track-to-substation feeder cable should be defined.
Track-to-track crossbonds, where used, should be placed and sized.
Supplementary (parallel) positive and negative feeder cables should be placed and sized.
17 Utility voltage considerations Utilities normally expect to deliver voltage to the
customer’s service entrance within ±5% of nominal (see ANSI C84.1 [B1]). The modeler may wish to evaluate the performance of the traction power system with the utility
voltage at its low normal limit, as with passive equipment (diode rectifiers for dc systems) this low utility voltage will pass through the traction power system. It may also be worth considering the utility voltage at its high normal
limit if it is found that regenerative braking is b eing limited by high line voltage.
IEEE Std 1653.3-2012
IEEE Guide for Rail Transit Traction Power Systems Modeling
Copyright © 2013 IEEE. All rights reserved.30 Table C.1, continued
18 Contingency design Under what failure conditions is the traction power
system expected to deliver normal, or fairly normal, performance? What degradation in performance is
acceptable under first and second contingencies? Many transit operations are designed so that any one substation may be off line without ov erloading the adjacent substations past their short term ratings. Off line may mean that only the power supply has been lost while switchgear remains in service to act as an equalizing bus between the tracks. Off line can also mean that the
switchgear is out of service, leaving no connection between the tracks at the substation location. The
difference between these two interpretations of off line can be significant.
19 Wayside loads Wayside loads powered from the traction power system
often include: Switch heaters Contact rail heaters
20 Track leakage characteristics This is of concern for rail-to-earth voltage calculations
IEEE Std 1653.3-2012
IEEE Guide for Rail Transit Traction Power Systems Modeling
Annex D
(informative)
Typical feeder characteristics
The following are typical data, or sources of data, for feeder characteristics applicable to modeling of traction power systems.