Alessandro Ruvio

Energy storage application in trolley-buses lines for a sustainable urban mobility

The focus of the present paper is pointed on trolley-buses lines, as solution for the urban mass transport in medium size cities. After a comparison in terms of economic and environmental features, with other mobility systems, the potential upgrading actions on trolley-buses line, that would improve its energy performance, are highlighted. In particular the energy storage application in power supplying system and on board the vehicles is deeply analyzed. To identify which of the two solutions involves in the highest energy saving, a study has been performed on the case of a trolley-buses line proposed for Cosenza city.

An environmental sustainable transport system: A trolley-buses Line for Cosenza city

In the present paper, a comparison among different types of urban mass transport systems, which can be implemented for medium-sized cities, is reported. For each mobility system, advantages and disadvantages, in terms of transport capacity and environmental impact, are highlighted. Then the focus is pointed on the trolley-bus solution. A real case study of deployment of this type of mobility system, for a medium size Italian city, is analyzed. The results of traffic and electrical simulations of the proposed trolley-buses system are exposed, including energy performance and economic evaluations.

Modelling and simulation of electric urban transportation systems with energy storage

Electrified guided vehicles are normally equipped with regenerative braking devices, while traction lines are supplied by non-reversible substation, thus allowing braking energy recovery only if nearby other vehicles are absorbing power. To enhance the effectiveness of regenerative braking, some energy storage can be installed along the line. Evaluation of its cost effectiveness requires time domain simulations, performed creating simulation models using general-purpose or specialized simulation languages. In this paper, two simulation tools are used. Their respective characteristics compared. The results obtained from both of them are also useful to evaluate the effectiveness of energy storage in a real-life urban case study.

Management policies for residential and tertiary users: A measurement campaign

In the present paper, a project for the application of control in heat pumps for residential and tertiary users are reported. The focus is pointed on the experimental test to validate the algorithms and management policies applies in four experimental sites, residential and tertiary, with different types of electrical equipment. The results of the experimental measurement campaign are reported to evaluate the energy benefits obtained with control actions.

Application of battery auxiliary substations in 3kV railway systems

In the paper is presented an auxiliary substation equipped with battery based energy storage system (Auxiliary Battery Substation - ABS) and the benefits for railway applications are shown. The proposed solution is able to reduce the effect of the peak current and voltage drops on weak traditional 3 kV feeding line during high performance trains traction. The ABS also increase the system efficiency by recovering energy during train braking phase and making it available again at the next starting time, minimizing the energy required to the main substation. An extensive simulation framework is performed on a real Italian 3 kV DC railway system feeding a new generation high speed train where the ABS supports conventional supply system. The simulation results confirm the effectiveness of the ABS in terms of peak current reduction and voltage drops compensation. Finally, The ABS allows reducing losses and increasing the energy saving in the railway feeding line.

Cross-country fault protection in ENEL Distribuzione's experimental MV loop lines

In the last years, high penetration of distributed generation (DG) has strongly affected public MV networks. In order to improve their reliability and availability, loop operation is being tested. This solution requires the installation of new line protection devices and the identification of appropriate settings against phase-to-phase and ground faults. This study refers to an experimental loop line operated by ENEL Distribuzione, the largest Italian Distribution System Operator (DSO). The paper deals with the behavior of the currently installed line protection during cross-country faults (CCFs), occurring both in radial and loop lines. MV network response has been preliminary evaluated by approximated formula (which allow a fast check of line protection performances), and then verified by accurate simulations based on a detailed Simulink network model. CCFs occurring inside and outside the loop line have been analyzed. Obtained results show that the zero-sequence and phase directional overcurrent (Blocking-Scheme supported) are generally able to selectively identify and clear CCFs. Nevertheless, if CCFs occur in the same overhead stretch of the loop line, the adopted protection scheme may fail.

Individual driving style impact on traction energy consumption in railway lines: A simulation model

The study reports some energy saving evaluations in rail transit due to appropriate driving styles. Several simulations were performed on an Italian 3 kV d.c. railway line feeding high-speed and two regional trains. Different scenarios about braking phases and coasting management are reported to quantify energy saving. Evaluation of the energy recovered during the braking phases for a traffic scenario is also reported.

A measurement campaign in a metro trains deposit/maintenance and repair site for PV production optimal sizing

The paper describes a measurement campaign conducted in a metro trains deposit/maintenance and repair site for the trains in operation on the metro line B of Rome. For the measurement campaign the network analyzer Chauvin Arnoux CA 8335 has been used. The measurements were conducted by performing a monitoring on general consumption and on relevant individual loads such as office building, lighting towers, lighting, lathe, etc. The knowledge of total energy consumption and of electrical loads allows the identification of possible different strategies for energy efficiency by using the PV production. Some evaluations are also conducted on the possible use of storage energy systems.

IVTs behavior in SF 6 switching transients: Fast front voltage impulse

Instrument Voltage Transformers (IVTs) introduce errors in power quality measure due to resonances effects at high frequency. The accuracy of IVTs, definite by standards, is only about nominal frequency and does not consider high frequency response. The paper reports the IVTs experimental analysis on resonances disturbances transferred to secondary side of Instrument Voltage Transformer. In particular the main results obtained from a laboratory survey on three currently marketed IVTs with same features but different manufacture are presented. IVTs are tested with very fast front voltage impulse whose waveform is similar to the characteristic one of SF6 switches operations.

A Simulink model to assess harmonic distortion in MV/LV distribution networks with time-varying non linear loads

Abstract The paper proposes a novel approach to modelling time-varying non-linear loads in power systems, based on demand conditions. The model allows a pre-evaluation of harmonic disturbances under variable conditions using normal and uniform distribution to randomize the electrical values of the non-linear loads and the related harmonic spectra. A measurement campaign conducted on an industrial area, a deposit/maintenance and repair site utilized for trains in operation on the metro line B of Rome, has been taken into account to verify the model performance. The methodology allows estimating the voltage total harmonic distortion at the point of common coupling. Through a statistical analysis, the harmonic distortion distribution via common normality tests was evaluated. The procedure has been used also to a harmonic disturbance pre-evaluation due to a future introduction of electric vehicles charging stations in the area.