Modular structure of the AC 800PEC control system

The modular structure of the system means that it can be adapted to any size of application,

from the largest industrial equipment and propulsion systems to compact products where space and cost

are critical.

All over the world, thousands of processors have proved their worth in a wide range of extremely

demanding applications.

Powerful hardware for efficient high-speed processing

The AC 800PEC combines the floating-point performance of a CPU with the flexibility and high-speed

capability of an FPGA.

The system is divided into three performance levels covering different cycle times.

Control tasks are assigned depending on their speed requirements:

– Very fast tasks, down to 25 nanoseconds (nanoseconds for FPGA tasks)

– Fast tasks down to 100 μs (microseconds for Matlab/Simulink tasks)

– Slow tasks down to 1 ms (milliseconds for control tasks)

The hardware architecture of the AC 800PEC is complemented by a three-level software architecture.

To support short processing cycles, the AC 800PEC offers a fast I/O system.

Depending on the speed of the I/O connections, data throughput times can be less than 100 μs,

 including the time required to read, process, write and transmit signals.

Implementing the AC 800PEC software at three performance levels provides excellent control and

communication capabilities.

The following software packages have been developed to support each specific high power rectifier

application.

Built for power control in the process industry

ABB has global expertise and know-how in the field of process control for industrial, marine and other

applications.

As a result, the AC 800PEC is a key controller for ABB industrial applications as well as third-party

products and systems.

The AC 800PEC is an efficient and flexible controller family. With short cycle times, fast (input/output) I/O,

processing power and advanced control using MATLAB®/Simulink®:

– Increased process quality and throughput

– Savings in development and engineering costs

– Reduced product energy consumption

– Reduced time-to-market for development projects

– Savings in engineering and software development labour and resources

– Improved return on assets (ROA)

– Hardware back-up trips for integration with fast COMBI I/Os

Arc Furnace Applications

– Stable arc detection

– Different control modes (constant current, constant power or constant resistance)

– Quick connection to Power Quality Systems (PQS)

Includes ELREG (electrode regulation; control of the anode hydraulic system) function:

– Manual electrode control (analogue or digital)

– Electrode quick lift function (with or without separate quick lift valve)

– Automatic arc extinguishing function

– Automatic re-arc function

– Adaptive electrode control according to furnace conditions or heating stage

– Stacked integral control circuit

– Voltage fluctuation measurement (stability index calculation)

– Arc detection/protection of the furnace roof

– Protection of the furnace top from arcs during arc extinguishing

– Hydraulic oil pressure monitoring and electrode protection

– Collapse detection

– High-pressure detection

– Control logic for backpressure valves

– Voltage monitoring to ground

– Voltage monitoring at the top of the furnace

– Automatic raising of the electrode after a furnace shutdown command (distance or position selectable)

– Shut-off valve control

– Electrode speed limitation to protect electrode and arm

– Future functions

– Automatic proportional valve linearisation

Check

– Automatic proportional valve linearisation

– Dynamic voltage setpoint control for stable melting processes

Aluminium applications

– AC 800PEC unit controller ↔ AC 800PEC master controller communicates via PEC – PEC fibre optic link

(100 μs)

– Can be independent of the main controller control unit

– Allows emergency operation (full smooth current control in emergency mode without AC 800PEC,

only in combination with DCS800 pre-magnetisation)

– Predictive maintenance functions can be included

– Open circuit, overcurrent, undervoltage and overvoltage protection packages included in software

– Newly developed OPC (Open Circuit Protection) stand-alone PLC (Programmable Logic Controller)

that can be used in conjunction with AC 800PEC main controller functions or

as a stand-alone protection during main board maintenance

– Controlled shutdown in the event of an event without immediate tripping → reduced disruption to the

production process

– Potline load fluctuation detection and load shedding integrated into the application software

– Load tap converter fast tap function to prevent DC current overloads during disturbances

– Special Potline-to-Earth Resistance Measurement System (PERMS) based on the AC 800PEC series

– Maximum power regulation

– Prevents excessive power consumption and supports your generator

– Maximum DC voltage regulation to stabilise the process

Preventive maintenance program

ABB has designed its maintenance schedule for all contactor

families, based on its technical knowledge of the products and

on its experience in the field.

The preventive maintenance program has the following main targets:

• Check the preservation and the efficiency status of the apparatus

• Anticipate the trend of deterioration of the contactors, signalling

the need for replacement of excessively worn out components,

where available, or suggest alternative solutions for bringing them up to date

• Increase the life cycle of the installation, proposing proactive

maintenance and replacing obsolete components.

Provided services

Considering the importance of the maintenance activity and

the required technical know-how, ABB guarantees professional

competence. Interventions are performed by ABB recommended

skilled technicians. After the inspection activities, ABB technicians

give all the indications related to the future maintenance needs and

any possible corrective actions, while releasing the final report.

Benefits

Preventive Maintenance creates value over the long-term by

• Providing the best management of maintenance costs, in

particular:– Less expensive direct costs of maintenance, by reducing

the charges due to urgent situations–  Less expensive indirect costs of the installation shut-down,

taking advantage of scheduled stops.

• Ensuring better efficiency and reliability of the equipment

• Extending the contactor’s life

• Guaranteeing the safety of the installation for longer time.

Provided services

Considering the importance of the maintenance activity and

the required technical know-how, ABB guarantees professional

competence. Interventions are performed by ABB recommended

skilled technicians. After the inspection activities, ABB technicians

give all the indications related to the future maintenance needs and

any possible corrective actions, while releasing the final report.