disturbances
• A special potline-to-earth resistance measure ment system based on an AC 800PEC family available (PERMS)
• Maximum power regulation- To prevent over-shooting of power consumption and to support your power generators
• Maximum DC voltage regulation for stabilizing your process

Electrical arc furnace applications
• Stable arc detection
• Different control modes (constant current,constant power or constant resistance)
• Fast link to power quality system (PQS)ELREG (electrode regulation; anode hydraulic system control) features included:
• Electrode manual control (analog or digital)
• Electrode fast lift function (with or without separate fast up valve)
• Automatic arc strike function
• Automatic arc restrike function
• Adaptive electrode control according to furnace behavior or heat stage
• Superimposed integral control circuit
• Voltage fluctuation measurement (stability index calculation)
• Arc-to-roof detection/protection
• Arc-to-roof protection during arc strike sequence
• Hydraulic oil pressure supervision and electrode protection
• Cave-in detection
• High-voltage detection
• Counter pressure valve control logic
• Voltage-to-ground supervision
• Roof voltage monitoring
• Electrode auto raise function after furnace off command (distance or position selectable)
• Blocking valve control
• Electrode speed limitation for electrode and arm protection
• Future features- Automatic proportional valve linearization check- Automatic proportional valve linearization- Dynamic voltage setpoint control for a stable melting process
Chemical applications:
• OLTC step compensation for smooth process control- IDC current step compensation for smooth current change when stepping up
• Power factor compensation by OLTC
• Predictive maintenance features can be included
• Software protection packages including:- DC over current protection- AC over- and undervoltage protection- AC phase unbalance protection- System unbalance protection for 12 pulse systems
• DC earth fault detection available by 3 voltmeter method
• Process pulse block loop with SIL 3 level
• Voltage ride-through in case of incoming voltage dips
Electrowinning industries (copper & zinc):
• IDC current step compensation for smooth current change when stepping up
• Power factor compensation by OLTC
• Predictive maintenance features can be included
• DC overcurrent protection
• AC over- and undervoltage protection
• AC phase unbalance protection
• System unbalance protection for 12 pulse systems
• Master DC current control for parallel rectifier units
• DC open loop detection during start-up
• DC open loop protection during operation
DC power supplies for graphite electrode plants
The graphitisation process demands a large variation of voltage and current from the DC power supply.
• Constant DC power suppy for the process irrespective of changing process resistance - Possible due to the very fast cycle times of AC 800PEC controller.
• Customer tailed process recipes can be added and modified from the operator panel in order to meet the specific customer requirements.
• After adding the corresponding recipes, the rectifier follows the predefined DC current, DC voltage and maximum allowed power set points, including all necessary graphitisation specific protection functions.
