•• Core Function: Provides comprehensive protection, control, and monitoring for synchronous and asynchronous generators in utility, industrial, and commercial applications.
Manufacturer: ABB Part number: ABB REX521GHHPSH07G
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REX521GHHPSH07G: Product OverviewThe REX521GHHPSH07G is a multifunction generator protection relay from ABB’s REX 521 series, designed to provide comprehensive protection and control for generators in various power generation applications. This advanced electronic relay serves as the primary protection device for generators, safeguarding against electrical faults and abnormal operating conditions that could damage the generator prime mover or associated equipment. Installed in switchgear panels or control cabinets, it continuously monitors electrical parameters including voltage, current, frequency, and power to detect fault conditions and initiate appropriate protective actions.The relay incorporates multiple protection functions specifically designed for generator applications, including differential protection, stator ground fault protection, overexcitation, loss of excitation, reverse power, and out-of-step protection. Beyond protection, it provides control functions such as automatic synchronization (sync-check) and integrated logic for complete generator management. The device features communication capabilities for integration into modern substation automation systems, allowing for remote monitoring, control, and data acquisition.
ABB REX521GHHPSH07G
REX521GHHPSH07G: Technical Specifications
•• Model Number: REX521GHHPSH07G
•• Manufacturer: ABB
•• Product Type: Generator Protection Relay
•• Rated Frequency: 50/60 Hz
•• Inputs: 3-phase current and voltage measurements
•• Protection Functions: Differential (87G), Stator Ground Fault (64G1/G2), Overexcitation (24), Loss of Excitation (40), Reverse Power (32), Out-of-Step (78), Overcurrent (50/51), Over/Under Voltage (27/59), Over/Under Frequency (81)
•• Control Functions: Automatic synchronization (25)
•• Communication Protocols: IEC 61850, Modbus RTU/TCP, DNP3.0, IEC 60870-5-103/104
•• Communication Ports: Ethernet, RS485, RS232
•• Display: Graphical LCD with user interface
•• Power Supply: 24-48 VDC / 48-250 VAC/DC
•• Operating Temperature: -25°C to +70°C
•• Certifications: UL, CE, IEC 60255
ABB REX521GHHPSH07G
Core Features & Customer ValueThe relay’s comprehensive protection suite eliminates the need for multiple discrete protective devices, reducing panel space, wiring complexity, and overall system cost. For protection engineers, this integration simplifies coordination studies and testing procedures. The high-accuracy measurements and advanced algorithms provide faster and more selective fault detection compared to electromechanical relays, minimizing equipment damage and reducing outage times during faults.The integrated automatic synchronization function allows for precise closing of the generator circuit breaker to the busbar, ensuring minimal mechanical stress on the generator and prime mover. This feature eliminates the need for a separate synchronizer, further reducing system complexity and cost. The relay’s event recording and oscillographic capabilities provide valuable data for post-event analysis, helping operators identify the root cause of trips and implement preventive measures.Typical ApplicationsIn diesel or gas generator sets for standby power systems, the REX521GHHPSH07G provides protection against faults while managing the synchronization process when paralleling with other generators or the utility grid. It ensures safe operation during islanded and grid-connected conditions.In industrial cogeneration facilities, the relay protects generators against internal and external faults while providing the necessary metering and communication functions for energy management and reporting. The reverse power protection prevents motoring of the generator if the prime mover fails.
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