ABB RXEDK 2H Microprocessor-Based Time Over

Description

Technical Specifications

Core Electrical Parameters

• Rated Voltage (Ur): Three standard variants: 2/5 V, 20/50 V, 100/200 V (selectable via terminal connection)
• Setting Range: Operate value adjustable from 0.2 to 1.6 times the rated voltage (Ur)
• Time Delay (U1): Definite time: 30 ms to 16.1 s; Inverse time: factor k = 0.05 to 16.1
• Time Delay (U2): Definite time only: 30 ms to 10 s
• Frequency Options: 50/60 Hz (standard), 50/60 Hz sharp filter, 150-180 Hz, 16 2/3 Hz
• Burden: Low burden on input voltage transformers, < 1 VA at rated voltage
• Reset Ratio: High reset ratio, typically > 95%
• Continuous Overload: 2x rated voltage continuously, 3x rated voltage for 10 seconds
• Output Contacts: 3 change-over (CO) contacts; Rated: 5 A at 250 V AC / 30 V DC
• Auxiliary Supply: Requires external DC-DC converter (RXTUG 22H) for ±24 V DC

Mechanical & Environmental

• Dimensions: 4U 6C (COMBIFLEX standard), compact modular form factor
• Mounting: DIN rail, panel cut-out, or 19″ rack mounting via COMBIFLEX system
• Weight: Approx. 0.5 kg
• Operating Temperature: -40 °C to +70 °C
• Storage Temperature: -50 °C to +85 °C
• Humidity: 5% to 95% RH (non-condensing)
• Vibration Resistance: Complies with IEC 60255-21-1
• Shock Resistance: Complies with IEC 60255-21-2

Standards & Certifications

• Compliance: IEC 60255 series, ANSI, C37.90
• Certifications: CE marked, suitable for global industrial and utility applications

Core Functions & Features

1. Dual-Stage Voltage Protection

• Independent Stages: Two fully configurable stages (U1, U2) for simultaneous overvoltage and undervoltage protection.
• Function Selectivity: Each stage can be independently set for overvoltage or undervoltage operation.
• High Precision: Microprocessor-based measurement ensures high accuracy and setting resolution.

2. Advanced Time-Delay Characteristics

• Definite Time (DT): Fixed, adjustable time delay for both stages, ensuring selective coordination.
• Inverse Time (IT): Available for stage U1 only; operating time decreases as the voltage deviation increases, providing faster response to severe faults.
• Wide Timing Range: Covers from milliseconds to seconds, adaptable to various system coordination requirements.

3. Built-In Filtering & Signal Conditioning

• Frequency Filters: Multiple built-in band-pass filters for specific frequency applications (e.g., 150-180 Hz for third harmonic detection).
• Harmonic Rejection: The 50/60 Hz sharp filter effectively suppresses third harmonic voltages, critical for stator earth-fault protection.
• Low Transient Overreach: Minimizes false operation due to system transients, especially for instantaneous functions.

4. Comprehensive Status Indication & Control

• LED Indicators: Green “In service”, yellow “U1 Start”, red “U1 Trip”, and red “U2 Trip” for clear visual status.
• Manual Reset: Front-panel push-button for resetting trip indicators.
• Remote Reset: Galvanically isolated binary input for remote reset via control signals.
• Self-Supervision: Internal watchdog and power-up self-test; LED flash codes indicate specific fault conditions (RAM, ROM, A/D converter).

5. Modular Integration & Flexibility

• COMBIFLEX Compatibility: Fully compatible with ABB’s COMBIFLEX system for easy assembly into multi-function protection schemes.
• Plug-and-Play: Designed for quick installation and replacement, minimizing downtime.
• Optional Accessories: Integrates with test switches (RTXP 18), DC-DC converters (RXTUG 22H), and auxiliary tripping relays (RXME 18) for complete protection assemblies.

Application Scenarios

• Power System Overvoltage Protection: Safeguards transformers, generators, and overhead lines against destructive overvoltages from load rejection or system faults.
• Undervoltage Protection: Prevents motor damage and system instability by tripping motors during voltage sags; used for bus transfer and load shedding schemes.
• Stator Earth-Fault Protection: Detects earth faults in generator/motor stator windings, especially when used with a 50/60 Hz sharp filter.
• Neutral Point Overvoltage Protection: Provides backup earth-fault protection for high-impedance grounded systems using zero-sequence voltage (3U0) from broken-delta PTs.
• Voltage Supervision & Control: Monitors bus voltages for “live/dead” indications, synchronism checks, and capacitor bank switching (VAR control).
• Generator Protection: Protects against loss of excitation, over-excitation, and abnormal voltage conditions.
• Industrial and Utility Substations: Integrated into control and protection panels for reliable voltage monitoring in power distribution networks.

Unique Advantages

• Multi-Functionality: Combines voltage measurement, protection, and timing in a single, compact module.
• Application Versatility: Wide setting ranges and filter options adapt to diverse power system frequencies and fault conditions.
• Reliability: High immunity to electrical noise, wide temperature tolerance, and robust construction for harsh environments.
• Ease of Use: Front-panel potentiometers and DIP switches allow for precise, on-line setting adjustments.
• System Integration: Seamless integration into modern protection and control systems via the COMBIFLEX platform.