Fryze reactive power of trams in effective stochastic recuperation processes

Oleh Bondar,Mikola Kostin,Olha Sheikina,Andrei Mukha,Svitlana Levytska

doi:10.1051/matecconf/201929401006

Abstract

Urban electric transport system, particularly tram systems, is not a direct current system not only in traction mode but in regenerative modes as both voltage on a collector and regenerative current are stochastic abruptly variable processes. The above- mentioned facts determine availability of Fryze’s reactive power in this system that flows from a railway substation to trams, leads to incidental losses of energy and significantly reduces its quality. So evaluation of power effectiveness of the system in electrical trams operation is impossible without determining the level of reactive power in this system. We have analytical expression of reactive power by Fryze. Numerical calculations for trams type T3D and T4D in regenerative braking modes are done. Probabilistic statistical data processing operation of reactive power expressions is done. It is determined that reactive power changes in the limit of 10…100 kilo-volt ampere reactive with mathematical expectation – 37,0 kilo-volt ampere reactive. Statistical allocation of random power values are different. Numerical calculations of incidental losses, energy of recuperation are done and they range supplementary – 20% from total losses. It is stated that coefficient of reactive power of system route of trams is exceeding permissible value 0,25.

Highlights

Municipal trams are the most widespread kind of electric rolling stock (ERS) of electric transport where there are often stops and starts and regenerative braking (RB)
Using the obtained expressions and monitoring of the material from experimental record 30 voltage U(t) and current I(t) implementations (Fig. 2) that are carried out according to the theory [9], numerical calculations of reactive power of trams of T3D and T4D types in regenerative braking modes were done during their operation on the routes 11 and 17 of Dnipro city
Abrupt random changes of voltage (Fig. 2, a) within 600...900 volt and current (Fig. 2, b) at interval 100...350 ampere lead to Fryze’s reactive power QF of trams is a random value that changes within 10...100 kilovolt-ampere reactive for one rail ride on the pointed route

Summary

Introduction

Municipal trams are the most widespread kind of electric rolling stock (ERS) of electric transport where there are often stops and starts and regenerative braking (RB). Electric power effectiveness of the tram system service is to be estimated according to the volume and the usage state of recuperative energy and taking into consideration such energy indicators as active power losses P and reactive power factor tg , that significantly depend on reactive power QF as to well- known expressions:

Results

Conclusion