Modern generator protection extends beyond fault detection and tripping.
On many projects, the same device must check synchronism, record disturbances and pass reliable data into the site’s control or substation automation system.
Protection, control, monitoring and communication are often engineered as parts of the same system rather than separate functions.
Generator Differential Protection • Synchroniser • Disturbance Recorder • IEC 61850 • Integrated AVR • Up to 9 Expansion Slots • Modular Hardware Platform
Generator protection is designed to detect internal faults, abnormal operating conditions and electrical disturbances that can damage the generator, transformer or associated equipment.
AQ-G257 combines multiple protection functions within a single platform, allowing protection schemes to be adapted to different generator types and operating requirements.
Key protection and monitoring functions:
Fault Protection
Generator Condition Monitoring
Voltage & Frequency Supervision
Generator operation depends on more than fault protection alone.
Before a generator can be connected to the power system, synchronisation conditions must be verified. During operation, stability limits, excitation conditions, voltage and frequency behaviour may also require continuous supervision.
AQ-G257 combines synchronisation, stability supervision and system monitoring functions within the same platform, helping operators maintain reliable generator operation under both normal and disturbed network conditions.
Key synchronisation and stability functions:
Generator Synchronisation
• Synchroniser
• Synchrocheck
• Dead Bus Synchronisation
Generator Stability
• Underexcitation Protection
• Pole Slip Protection
• Power Factor Protection
System Frequency & Voltage Supervision
• ROCOF Protection
• Overfrequency Protection
• Underfrequency Protection
• Overvoltage Protection
• Undervoltage Protection
• Volts-per-Hertz (V/Hz) Protection
AQ-G257 provides event recording, disturbance analysis and operational monitoring functions that help engineers investigate system behaviour and analyse protection operations
Event Recording
Disturbance Analysis
Operational Visibility
AQ-G257 can be adapted to additional monitoring, control and communication requirements without introducing separate devices for individual functions.
Additional I/O Capacity
• Expansion of digital inputs and outputs for plant-specific control and monitoring requirements
• High-speed output modules for applications requiring fast trip signalling
• Milliampere input and output modules for process integration
Generator Temperature Monitoring
• Up to 16 RTD inputs
• Thermal alarming and tripping based on temperature measurements
Additional Protection Functions
• Optional arc protection module
• External RTD and process signal expansion modules
Communication & System Integration
• Additional Ethernet and fibre-optic communication options
• IRIG-B time synchronisation
• HSR and PRP network redundancy
• Serial communication interfaces
| Parameter | AQ-G257 |
|---|---|
| Current Inputs | 10 |
| Voltage Inputs | 4 |
| Standard Digital Inputs | 3 |
| Standard Digital Outputs | 5 |
| Expansion Slots | 9 |
| Event Recorder Capacity | 15,000 records |
| Disturbance Records Capacity | 100 records |
| Sampling Frequency | 3.2 kHz |
| RTD Expansion | Up to 8 inputs per module |
| Communication Protocols | IEC 61850, IEC 60870-5-101, IEC 60870-5-103, DNP3, Modbus RTU/TCP, SPA |
| Power & Energy Accuracy | 0.5% |
| Optional Power & Energy Accuracy | 0.2% |
Protection and synchronisation for utility-scale generating units and power stations.
Generator protection for renewable energy facilities, hybrid plants and grid-connected generation.
Protection and control for combined heat and power generation systems.
Protection and control for industrial generation systems and on-site power plants.
Generator protection for standby generation and mission-critical power systems.
Protection and synchronisation for grid support and reserve power generation.
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