REX640 introduces high-speed transfer to secure electrical supply for critical parts of the power system

REX640 introduces high-speed transfer to secure electrical supply for critical parts of the power system

The capability of REX640 to perform automatic high-speed transfers ensures fast recovery of electrical supply for critical loads, minimizes the impact on the manufacturing process – and saves money.

ABB’s pioneering all-in-one protection relay for advanced power generation and distribution applications, REX640, continues to support the increasing digitalization of substations. The third functionality upgrade includes technological innovations, enhances the user experience and safety, and fosters stability in the modern grid. Product Line Manager Olli Rintamäki said: “The functionality upgrade further strengthens REX640’s position as the market-leading protection relay for advanced medium-voltage protection and control solutions. It clearly shows our commitment to provide our customers with the latest developments and innovations within the industry.”

High-speed transfer to safeguard the manufacturing processes
The release of new functionality makes it possible to use REX640 as a high-speed transfer device (HSTD), which continuously supervises the main feeder, automatically disconnects a failing incoming feeder and transfers the busbar load to another feeder instead. This ensures an optimal transfer with a minimum impact on the manufacturing process and no risk of damage to the equipment – saving time and money. High-speed transfer is typically required where electrical supply for motors operating critical parts of a manufacturing process is secured by connecting an alternative feeder on standby. This is often the case in the petrochemical, pharmaceuticals and semiconductor manufacturing industry, as well as in electrical power generation plants.

Optimal balance between safety and supply quality in compensated and isolated networks
With cable networks continuing to grow in size and proportion, creating new demands and challenging earth-fault protection, ABB is expanding its already impressive earth-fault protection portfolio by adding touch voltage-based earth-fault protection. It represents an entirely new approach to earth-fault protection as it estimates the fault current as well as calculates the resulting hazardous touch voltage at the fault location, instead of only measuring the fault current in the substation like conventional earth-fault protection does. The result is an optimal balance between safety and supply quality in compensated and isolated networks, minimizing the risk of hazardous fault conditions and unwanted customer outages. The ability of touch voltage-based earth-fault protection to fully adapt to changes in the network topology further improves safety and adds to the convenience, ensuring the network continues to remain optimally protected.

Prevention of breakdown of the generator shaft bearing
As part of the improvements to generator protection, REX640 introduces generator shaft current leakage protection, typically required in hydropower plants and turbo generator installations. This makes it possible for REX640 to detect leakage current caused by the insulation of the main shaft bearing being damaged, and ultimately prevent breakdown of the bearing. `

Increased protection accuracy with advanced rotor thermal overload protection
Another addition is thermal overload protection for rotors in asynchronous machines. Basing the protection on the estimated rotor slip percentage, which in turn is based on the measured stator load current, represents an advanced way of implementing rotor thermal overload protection. This makes the estimates of the thermal load condition of the rotor much more accurate, which significantly increases the protection accuracy.

Improved stability in the modern grid
To support maintaining stability in the modern grid the power transformer voltage regulator of REX640 is now capable of managing the changing direction of the power flow. For instance, a weak grid in combination with a larger distributed generation plant with considerable production capacity, such as a wind farm, requires the capability of adjusting the voltage according to the direction of the power flow, to ensure grid stability is maintained.

Support for an increasingly digitalized grid
Other significant developments include the addition of IEC 61850 Edition 2.1 to support the digitalization of the grid. Introducing the possibility to use the human-machine interface (HMI) of REX640 as a 64-channel alarm annunciator significantly enhances the user experience by offering clear visual alarm indications and descriptive channel-specific information. Adding monitoring of diesel generator sets running in parallel allows REX640 to identify and disconnect an oddly behaving diesel generator set before the fault cascades into the neighboring units and causes a complete shutdown.

To learn more about the latest developments in REX640, please register for the webinar on March 22. For further details on REX640, please visit the product page and campaign page, and use our new intuitive and easy-to-use e-business platform, ABB Relays-Online, to further explore and configure your unique REX640 relay.


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