Power Supply for Metro Platform Screen Doors (PSD)

Context

Platform Screen Doors

Every day millions of travelers use the subway all over the world. When transporting people by metro, it is necessary to keep them safe, to provide them with comfort and to limit their waiting time to a minimum. This is what Platform Screen Doors (PSD) are made for.

Platforms screen doors consist in automatic doors along platformsto isolate travelers from the subway traffic. They work as a barrier installed at the edge of the platforms and are synchronized with the on-board doors of the train.

Challenges

Metro operating companies are implementing platform screen doors when revamping stations, automating the lines or building new lines. However, their goal remains the same: increase passengers’ safety and comfort as well as the efficiency and reliability of the transportation.

In order to do this, metro operating companies are looking for long-term and flexible solutions enabling the platform screen doors to be operational 7/7. To ensure a high level of service, reliable power and supervision solutions are essential. That is where Alpha Innovations comes in to deploy its expertise.

Alpha Innovations Solution

Power systems

Voltages and signals to control the door motors can vary depending on the motor types as well as the control systems. Thanks to our wide range of modules, we are able to combine the right converters with the right voltages, in AC or in DC. Moreover, our converters are compliant and compatible with railway signaling architecture requesting specific insulations for instance.

We often collaborate with platform screen door suppliers for the assembly and tests of complementary functions designed by them and integrated inside the power cabinets or in the external cabinets.

Our power system solutions include power shelves ACE306 and CAR30100TP-A converters, their protections and controls as well as a power backup.

Power backup and reliability can be ensured by different means:

Redundancy of the sources: two sources of power – when one fails, the other one takes over
Integration of batteries in the power system: when the grid is not available, batteries will power the PSD systems with a 0ms transfer time
Redundancy of the DC and AC converters

Metro operators sometimes combine these means. We have experience with all these situations and can deliver the means they need in a single power cabinet.

Monitoring & Control

Our power supply solutions are placed in technical rooms together with other equipment of the metro station infrastructure. Our monitoring and control solutions not only manage our power systems, they can also manage all equipment inside and outside the technical rooms such as third-party sensors and components along the tracks.

For example, our local COMPAS controller can be integrated into any cabinet and report status (power source, alarms, …) through various communication bus. We also offer a multi-site supervision and management solution, Inview MESH, to have a real-time overview and control of the entire infrastructure enabling the anticipation of components’ end-of-life.

All this enables metro operating companies to ensure the continuity of their services and ease maintenance in a complex environment by providing a summary view of their infrastructure.

Why they trust us?

Subway infrastructures imply huge investments and few changes over time. Therefore, metro operating companies are looking for long-term suppliers. We make it a point of honor to do everything we can to ease our collaboration. How?

Documentation & Tests

As a supplier, we commit to supporting our customers for 20 to 30 years. We ensure long-term reliability by providing complete, shared documentation and conducting rigorous functional and security testing compliant with local standards.

Obsolescence Management

One of our strengths is the modularity of our systems facilitating the replacement of any component in case of an obsolescence announcement, without replacing the whole installation.

All Around The World

We have a large field experience in power supply and monitoring for Platform Screen Doors, all over the world.

Results

Safety

Full compliance with European and international marking requirements.

Reliability

Proven 24/7 operation across multiple global metro networks.

Maintenance

Real-time alerts reduce mean time to repair (MTTR) by identifying faults before they cause a shutdown.

Frequently asked questions

COMPAS is an open, protocol-agnostic industrial IoT gateway developed by Alpha Innovations. It connects sensors and equipment via standard protocols (Modbus, MQTT, RS485, CAN, Ethernet) to collect, monitor, and control energy data in real time, both on-site and remotely.

Yes. COMPAS is designed to be hardware and vendor agnostic. It supports all major industrial communication protocols including Modbus RTU/TCP, MQTT, and can be extended with additional I/O and communication boards to match specific site requirements.

Inview MESH is a cloud-based monitoring and management platform that centralises data from multiple COMPAS deployed across different sites. It provides unified dashboards, alerts, and reporting for multi-site energy management.

We rely on several reliability mechanisms: redundant power supply sources, integrated battery systems (with a 0 ms transfer time), and redundancy of the converters themselves. All these components can be centralized within a single power cabinet.