The charging facility is always in view.

Image source: © Stadtwerke Jena / Anna Schroll

This paper will describe how the Jena public transport system in Germany monitors the charging piles of its electric bus fleet and uses advanced diagnostic functions to improve its availability and optimize maintenance activities.

In Jena, Germany, electric vehicles have appeared in the form of trams and have been in use for 120 years. With the emergence of diesel powered bus fleet, the city has gradually formed an efficient public transport system. Last year, electric vehicles were included in the city’s public transport operation. The first three electric vehicles put into operation have started regular service in 2020, aiming to reduce carbon dioxide emissions (about 53000 kg per electric bus per year) and particulate matter emissions and noise pollution in the urban area.

The essence of public transport is to improve and maintain its long-term operation through smooth and punctual operation. In this case, the operation of tram especially needs reliable and uninterrupted power supply, which is the responsibility of the power supply department of Jenaer nahverkehr company, the urban public transport operator. Nevertheless, in rare cases, system technical faults may still occur. In order to minimize the impact of faults on the operation process and passengers, it is necessary to reduce the downtime. This requires reliable control and remote control system, which can be implemented through pcvue SCADA software.

For many years, Frankfurt automation business department of German actemium company has been a partner of Jena public transport system, responsible for implementing and further developing power supply control and remote control technology, and monitoring signal and safety systems.

The power supply department is responsible for maintaining the newly introduced electric bus charging facilities. They want to integrate the charger into the control system, so actemium automation in Frankfurt is entrusted to perform this operation.

The main objective of this expansion is to remotely monitor the charging facilities through the power supply department, so as to find and avoid faults as soon as possible. At the same time, it is necessary to minimize the travel time of service personnel, especially in the same city, mainly because the city is located in the Saleh River Valley and the traffic density of a few routes is very high.

The existing control system has formed a set of standards, which can process data through various industrial communication protocols and remote alarm, so as to realize visualization, archiving and data exchange with external systems.

Ocpp – driver for communication with charging station

The open standard protocol ocpp (open charging point protocol) is generally used for charging station monitoring to ensure the interoperability between products of different manufacturers.

With the latest version of pcvue, the manufacturer arc informatique can provide communication drivers for ocpp protocol, which can support existing 1.6-j and 2.0.1 protocol versions and 1 and 2 security profiles. The software also overcomes the typical ocpp problem, that is, a charging station can only communicate with one charging station management system (CSMs). Using the agent function, the ocpp information of the charger can be transmitted to the third-party system. This shows that the typical feature of open pcvue system is that it itself has a wide range of data exchange options.

Integrated operation function

The new user interface entrance can be seamlessly integrated with the existing system. It displays the charging stations distributed in the whole urban area as symbol marks in the form of map. For users who have been familiar with the existing functions and operation concepts of the control system for many years, the learning curve of the new visualization function is very short, which is also reflected in the monitoring area of the charging station.

Data analysis and monitoring

The core function implemented by actemium is alarm and log data management, which allows accurate fault analysis in real-time operation and historical data evaluation. Its alarm system is convenient for the personnel on duty to diagnose the fault in advance through the safe remote access system of the public utility unit, and then adjust or take appropriate measures.

In addition, since the traffic control center is connected to the charging infrastructure, its dispatcher workstation can display the location of the bus at the corresponding charging point in real time and point out the faults affecting the operation. This means that adjustments can be made quickly in the vehicle deployment plan to avoid cancelling or delaying the route. Afterwards, the maintenance personnel can also determine the real cause.

Image source: © Jenaer Nahverkehr GmbH

Alarms with particularly high priority will be sent to the mobile terminal of standby service in the form of remote information.

Users of the system can display and monitor the ongoing charging process through trend data, so that they can intuitively compare all measured values, such as current, voltage and power values. Similarly, it can recall and contrast the completed charging process from the transaction history. It can also identify the corresponding vehicle and record its current state of charge.

Users only need to press the button to export the transaction history, or automatically export and store it as weekly and monthly reports. Special attention should be paid to the energy consumption of each vehicle and charging process, as well as the number of wrong transactions.

The user interface of the system further realizes the following functions:

-Charging station access management system

-Lock or unlock the charging station for use

-Remotely activate or cancel the charging process

-Storage and retrieval of charging station specific documents

Its practical benefits were demonstrated in just a few weeks

Chris Tian Zeh, test and maintenance engineer of Jena public transport system in Germany, is confident in the solution.

“After integrating the electronic charging station, we can see all the operation status in the monitoring system, which provides us with the option of immediate intervention. Therefore, the charging facilities are fully integrated into the operation workflow of the power supply department. The practicability of the system has been proved in daily operation in just a few weeks, especially in controlling the temperature fluctuation of the charging station.”

With the implementation of charging facilities in the control and remote control system, the power supply team is ready for the planned increase of electric bus fleet and related expansion of charging facilities.

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