Automation Design for a safe and efficient operating tank farm

The Control System (CS) is responsible for the full operational functionality of the Fuel Depot. Parts of this functionality deal with all technical processes required for the normal day to day operations, including but not limited to receipt, storage and delivery of the aviation fuel. The CS interfaces with other subsystems such as Tightness Control System, Tank Gauging System, Emergency Shut Down, Fire Alarm System and Security/CCTV system.

System Description

The proposed general system architecture reflects the experience of hansaconsult (HC) as the designer and supplier of automation systems for airport refueling facilities throughout the world, especially at New Athens International Airport (design, engineering and TCS® installation by HC, delivery by third parties), Munich Airport (design, engineering and TCS® installation, delivery by HC) and Dortmund Airport (design, engineering and delivery by HC).

Control and monitoring of the plant are usually carried out at three locations:

The HMI layer will be implemented on the industry standard Personal Computers and located in the Control Room. It will consist of two identical and redundant operator workstations, which will communicate with two redundant PLC Nodes (Process Control Layer) via industrial Ethernet network. The operator workstations will also be connected via a secondary Ethernet network, through which the redundancy will be implemented. Each workstation will provide, without limitation, all the different displays, as specified. Further workstations (up to 16 in total) can be accommodated in the same manner.

This layer shall consist of nodes comprising redundant Programmable Logic Controllers (PLC). Both PLC’s will be connected to the redundant loop and will have full access to all data available from the local substations dedicated to the area served by this node.
Each node will function according to the principle of the active redundancy in a “hot stand-by” manner (automatic switching in the event of malfunction). In order to achieve a seamless switchover, the nodes will have the same user program, data blocks, process image contents and internal data (timers, counters, memory bits, etc.). Both PLC’s forming a node will be up to date at all times, so that each can take over control in case of a failure of the other one.

This layer provides low level services, such as direct communication with sensors, controls and actuators. This layer shall be implemented by the means of local I/O substations. The sub-stations shall not perform any specific functions but expose data received from the field instruments and indicate faulty conditions reported by those instruments to the next layer. The sub-stations shall not require any programming. They shall be installed at all important information nodes.

The substations shall exchange data with the higher layer via a fiber optic cable, which should form a redundant closed loop, as specified, and enable PROFIBUS communication. This should ensure both electromagnetic compliance and lightning protection throughout the system.

Modes of Operation