The Vredesbrug is a lifting bridge with a one-sided drive and isostatic synchronization cables. The heavy bridge is balanced by two heavy counterweights and a significant weight of cables. In the event of an emergency stop (mass inertia) or power failure (variable direction of the load torque), the bridge must remain manageable. To this end a fourquadrant flux vector control is coupled with an alternating current machine with direct current characteristics controlled by a redundant safety PLC with SIL3 safety function.
The movement of the bridge is subject to a number of stringent requirements
- The speed of movement must always be under control.
- In the event of an emergency stop or power failure, the kinetic energy must be disposed of in a progressive and controlled manner.
- Availability and reliability must be the highest possible.
The bridge can be operated in 4 ways
- By means of the SCADA control system in the local control room
- By means of switch control in the local control room
- By means of an emergency control in the local control room
- By means of remote control over glass fibre from the Oostdijk central control centre
Low-voltage installation of power current and low-voltage current
Risk analysis and risk reproduction measures
Redundant PLC with SIL3 safety function and SCADA solution
General low-voltage board with 4-quadrant flux vector drive technology
PLC and SCADA control and visualisation
Redundant alternating current engine with direct current characteristics as a dynamic break
Mechanical central reductor and spacers
Safety breaks and action breaks
Study of the drive system: a preliminary study with a significant part risk analysis was done based on the client´s design. It is after all a special challenge that a moving bridge drastically changes the reduction in loads during movement. This creates important challenges for the safety design. Especially the need for perfect control of the movement and keeping the imbalance bridge counterweight cables within strict limits were challenges.
The studies of the power and drive electronics started at the same time.
The implementation phase started after approval by the Board. In this phase the cabling was placed on the wharf, the ALSB and control board produced and the PLC and SCADA software written.
The hydraulic and mechanical equipment was also fabricated during the implementation phase and the synchronisation control was programmed.
Because the installation was so unique and did not allow for any major out-of-service period, a test set-up outside the installation and extensive FAT testing were necessary.
Safe and reliable design of industrial heritage
The biggest challenge related to the project was without doubt the special design of the drive that focused on a safe and reliable operation. The bridge had to remain fully available during the renovation, which was a particular challenge. Today, the Vredesbrug, classified as industrial heritage, is adapted to the most up-to-date standards of safety and efficiency. It creates a secure connection between the two banks of the canal.