Railway infrastructure projects require maximum reliability under a wide range of conditions and over long periods of time. Accurate measurements over long periods of time - often in remote locations - are therefore essential for innovative solutions in this field. A self-sufficient power supply with remote monitoring for track measuring points was realised with one of our customers from the rail industry.
Initial situation and system design
The customer’s request for this project was the design of a 24V stand-alone system for two extensive measuring stations. In addition to the spatial distance of several hundred metres between the PV, control cabinet and measuring systems, the special requirements for a system in the immediate vicinity of railway tracks with overhead lines had to be taken into account during planning. A special mounting system had to be designed for the photovoltaic system, which allowed installation on a slope with an inclination of up to 38°.
Self-sufficiency of at least three days was required in all seasons and even in poor weather conditions, as well as complete monitoring of the entire energy supply system. External equipment such as fuses, the ventilation system, surge arresters and battery balancers are also monitored. In the event of a low state of charge, a safety shutdown was to be provided to protect the batteries - following a warning from the monitoring system.
The following components were designed and planned by Sailectron Services GmbH technicians using the performance data provided by the customer:
- Structure and design of the energy management system
- Battery type and capacity
- PV system with substructure and mounting
- Remote access incl. LTE transmission system
- Vandalism-protected switch cabinet system
- Additional earthing system in the immediate vicinity of the railway system
Components
Six Victron Energy 12V/200Ah AGM Telecom batteries were selected for the project to ensure a wide operating temperature range and long service life. The widely used battery format ensures a long product life and the certainty that the system can be quickly equipped with new batteries if required. Battery balancers ensure that the 12V blocks remain balanced and alert the system if one of the batteries has a problem. A Victron BatteryProtect protects the system from deep discharge and disconnects the loads before the AGM batteries are damaged.
A Victron Energy Blue Smart IP22 Charger enables the batteries to be charged via a 230V AC power supply - this charger is only intended as a backup, as the system will normally run in stand-alone mode.
Eight 435Wp solar modules (TRINA TSM-435NEG9R.2) supply two SmartSolar MPPT 250/60-MC4. At 3.48kWp, the rather large solar system ensures that the system is regularly fully charged even in poor orientation and/or sub-optimal weather conditions.
A Victron Cerbo GX in conjunction with a GX Touch 50 is used for system monitoring. This allows both local monitoring and remote monitoring of all system parameters, including the integration of temperature sensors and digital inputs.
Installation
The assembly in another EU country was carried out by one of our teams in close cooperation with the customer’s technicians. The control cabinets that were prefabricated in our workshop were unloaded and positioned on site using a crane. Once the photovoltaics and the measuring point had been installed, the components were interconnected and put into operation.
Monitoring
The Victron Cerbo GX continuously supplies live system data via an LTE modem, which can be accessed via the Victron VRM platform. In addition to the state of charge, the battery voltage and the DC load, temperatures and states of various operating resources are recorded. In addition to proactive maintenance, this also enables precise analysis of the characteristic values for the design of other similar systems.
The customer and our support department receive alarms via e-mail if the set characteristic values are exceeded or not reached, so that reliable operation of the system is always ensured.
Technical data
- DC voltage: 24V
- Energy storage: 6x 12V/200Ah AGM Telecomm Batt. (M8)
- Photovoltaics: 8x TRINA TSM-435NEG9R.2
- PV charge controller DC-coupled: 2x SmartSolar MPPT 250/60-MC4
- Monitoring: Victron Cerbo GX with GX Touch 50 and connection to VRM
