Report on Meeting on NiCad Battery Sizing Standard

October 26,1999

At

LTK Engineering Offices

 

 

 

The subject meeting was held at LTK engineering offices in Blue Bell, PA. on October 26 at 10:00 AM.   Those in attendance were:

 

            Bob Cerra                LTK Eng.     215-542-0700                      bcerra@ltk.com

 

            Claude Gabriel              LTK Eng.     610-337-1835                      cgabriel@erols.com

 

Sachit Kakkar             SEPTA             215-580-8057                      Askt2@aol.com

 

Stanley Kwa                 NYCT              212-492-8307                 CEEnTSo7SK@aol.com

 

Ted Mavronicolas            SAFT               410-771-3200            ted.mavronicolas@saftamerica.com

 

Jim Mc Dowall              SAFT               203-239-4718            jim.mcdowall@saftamerica.com

 

Tom McGean                        TJMPE             757-789-5166                 t.j.mcgean@ieee.org

 

John Pesuit                        STV Inc.            212-614-3311                 PesuitJT@stvinc.com

 

Vince Young              C&D                215-619-7877                 vyoung@cdtechno.com

 

Norm Vutz                        LTK Eng.            215-580-3551                 nvutz@ltk.com

           

 

 

The objective of the meeting was to explore options for a standard prescribing the method to determine NiCad battery sizing when given the load profile and the battery operating conditions.  The Auxiliary Power Rail Interface standard IEEE standard P1476 which is now in the balloting process provides the guidance and procedures to determine the Load Profile (plot of Current Vs Time) for the current draw on the battery during its required discharge period.  It does not provide any guidance or specifications on how to determine the electrical or physical sizing of the battery required to support the load profile as this is beyond the charter for an interface standard. 

 

There presently exists a standard IEEE Std 1115 which describes recommended practices for determination of the electrical size of NiCad batteries for Stationary applications.  In the meeting we addressed the question as to whether it would be advisable to recommend modifying the IEEE Std 1115 to include rail transit applications or to recommend development of a new standard specifically geared to rail transit.

 

Jim McDowall who is the chairman of the IEEE Std 1115 gave us a brief overview of that standard and its status.  It soon became apparent that the applications had many unique and different requirements that it would be unadvisable to seek one standard to cover both applications.  The differences are:

 

·        Stationary applications have a battery system that is on standby and usually fully charged when called upon to support the load profile while rail transit batteries can be in a partial state of charge when required to support the load profile because of current draws caused by traversing rail gaps or applications of track brakes.

·        Rail applications frequently have dedicated or high rate chargers to replenish the battery quickly after periods of high discharge, whereas stationary applications have the battery on sustained long periods of discharge and can rely on float charge.

·        Rail applications have shock and vibration considerations of mobile application whereas stationary applications do not.

·        Stationary applications do not take into account duty cycle the battery sees such as disconnected power at night and having batteries partially discharged.

 

 

Based on the above considerations, it was decided that we would recommend the development of an IEEE,  NiCad battery sizing standard specifically for rail transit applications.  We then addressed formulation of considerations required for the submission of a PAR.  The following provides an outline of what was discussed and formulated with respect to scope and purpose and other guidelines.

 

 

·        Title:  Recommended Practice for Sizing Nickel- Cadmium Batteries for Rail Passenger Cars.

·        Purpose:  This standard provides standardized methods for electrical sizing of Nickel-Cadmium batteries for application and use aboard rail passenger vehicles.

·        Scope:  The specific wording was not developed but certain inclusive and exclusive factors were developed that should be included in the wording of the scope. These are: Inclusive (Auxiliary power, on-board battery applications, factors that influence battery capacity).   Exclusive:  (motive power, batteries used for DMU’s Diesel Multiple Units, physical size of battery, charger sizing, qualification and testing)

·        Coordination:  The standard should reference and be coordinated with the requirements of :       WG-6   IEEE Std P1476                                                  WG10   Standard being developed for Physical sizing of Ni-Cad                               batteries for rail transit application.                               PRESS Standard developed for batteries for commuter rail                          application.                                                 IEEE Std  1115 (SCC-29)  Committee for Std 1115                            IEC  TC21 committee for IEC rail transit electrical batteries.

 

We discussed the selection and volunteer of someone to chair the working group to develop the standard.  There are several considerations but we were unsuccessful in obtaining a chairperson.  This standard will be discussed further during the RTVISC meeting in New Jersey Transit on November 9,1999.