RXHL/RAHL – Compact Overcurrent Relays RXHL 4xx and Line Protection RAHL 4xx

The RXHL/RAHL 401, 411, 421, and 422 are four overcurrent and earth-fault protection relays designed for various power system applications. They also provide backup protection for terminals such as the 650 and 670 series across all voltage levels, including Extra High Voltage (EHV) systems.

Furthermore, these relays offer time-current characteristics according to IEC 60255-3, along with a thermal replica overload function, RI curve, and a special logarithmic curve for earth faults in EHV systems. They can also detect intermittent phase and earth faults, helping improve protection reliability. Additionally, their flexible design makes them suitable for retrofitting and replacing older electromechanical and static relay designs.

RXHL/RAHL 401

The RXHL/RAHL 401 provides dedicated phase overcurrent and earth-fault protection through multiple protection stages.

• Three-Stage Phase Overcurrent Protection: Provides I>, I>>, and I>>> stages for alarm and trip functions.

• Three-Stage Earth-Fault Protection: Offers three stages for earth-fault alarm and trip functions.

• Replacement Compatibility: Supersedes the earlier RXIDK 4 and RAIDK 400 relay models.

RXHL/RAHL 411

The RXHL/RAHL 411 combines overcurrent, thermal overload, earth-fault, and circuit breaker protection. Moreover, its additional protection functions support reliable power system operation.

• Three-Phase Overcurrent Protection: Provides three time-delayed or instantaneous stages (I>, I>>, I>>>) with alarm and trip functions.

• Thermal Overload Protection: Monitors three-phase thermal conditions through the Q> alarm and trip functions.

• Earth-Fault Protection: Offers three time-delayed or instantaneous stages (IN>, IN>>, IN>>>) with alarm and trip functions.

• Circuit Breaker Failure Protection: Detects failures using three-phase and neutral current measurements. It also provides selectable timing logic and retripping for single-pole and three-pole trip applications.

• Pole Disagreement Protection: Identifies pole disagreement through separate phase current measurements.

• Automatic Reclosing: Supports up to four reclosing attempts as an optional function.

• Additional I/O Module: Offers an optional board with four optocoupled inputs and four relay outputs.

RXHL/RAHL 421 for High-Impedance Earthed Systems

The RXHL/RAHL 421 is designed for high-impedance earthed systems. It combines overcurrent, thermal overload, directional earth-fault, and additional voltage protection functions.

• Two-Phase Overcurrent Protection: Provides three time-delayed or instantaneous stages (I>, I>>, I>>>) with alarm and trip functions.

• Thermal Overload Protection: Offers three-phase thermal overload monitoring through Q> alarm and trip functions.

• Directional Earth-Fault Protection: Provides three time-delayed or instantaneous stages (IN>, IN>>, IN>>>) with alarm and trip functions.

• Neutral Point Voltage Supervision: Uses a neutral point voltage stage to enable directional earth-fault protection. It also provides definite-time backup protection.

• Flexible Operating Characteristics: Supports unidirectional or bidirectional operation. Users can also change the characteristic angle manually or remotely between 0° and -90°.

• Neutral Point Overvoltage Protection: Provides one stage of time-delayed neutral point overvoltage protection.

• Intermittent Fault Management: Includes logic to detect and clear intermittent faults.

• Circuit Breaker Failure Protection: Monitors three-phase and neutral currents with selectable timing logic.

• Pole Disagreement Protection: Detects pole disagreement through separate phase current measurements.

• Automatic Reclosing: Supports up to four reclosing attempts as an optional function.

• Additional I/O Module: Provides an optional board with four optocoupled inputs and four relay outputs.

RXHL/RAHL 422 for Solidly Earthed or Low-Impedance Earthed Systems

The RXHL/RAHL 422 is designed for solidly earthed and low-impedance earthed networks. In addition to overcurrent and thermal overload protection, it provides directional and non-directional earth-fault protection.

• Two-Phase Overcurrent Protection: Provides three time-delayed or instantaneous stages (I>, I>>, I>>>) with alarm and trip functions.

• Thermal Overload Protection: Monitors three-phase thermal conditions through Q> alarm and trip functions.

• Directional and Non-Directional Earth-Fault Protection: Offers three time-delayed or instantaneous stages (IN>, IN>>, IN>>>) for effectively earthed networks.

• Low Polarising Voltage: Supports polarising voltage levels down to 0.5%.

• Adjustable Characteristic Angle: Allows users to set the characteristic angle between 0° and 90°.

• Circuit Breaker Failure Protection: Monitors three-phase and neutral currents with selectable timing logic.

• Pole Disagreement Protection: Detects pole disagreement through separate phase current measurements.

• Automatic Reclosing: Supports up to four reclosing attempts as an optional function.

• Additional I/O Module: Provides an optional board with four optocoupled inputs and four relay outputs.

Common Features

The RXHL/RAHL relay series offers several common features that simplify configuration, monitoring, and maintenance. These functions also help improve protection coordination and operational reliability.

• Intermittent Fault Detection: Includes logic to detect and clear intermittent faults.

• Flexible Binary Inputs and Outputs: Provides two binary inputs for blocking or enabling functions and five configurable binary output relays.

• Expandable I/O Configuration: Supports an optional module with four additional inputs and four outputs for the 411, 421, and 422 models.

• Self-Supervision: Monitors internal relay conditions and provides selectable alarm outputs through a relay contact.

• Dual Setting Groups: Allows users to select between two setting groups through a binary input or HMI.

• User-Friendly Interface: Provides an easy-to-use HMI for configuration and operation.

• Service Value Monitoring: Displays primary or secondary service values and disturbance information through the fully graphical HMI.

• LED Status Indication: Provides three LEDs for in-service, start, and trip indications.

• Input and Output Testing: Allows engineers to test binary inputs and outputs directly through the HMI.

• Flexible Mounting Options: Supports installation in 19-inch equipment frames, panel mounting cases, and DIN-rail adapters.