Product Short Description
Product Overview
Specialized fault detection module for large synchronous generator rotating excitation rectifier bridge, real-time monitoring of excitation diode open-circuit, short-circuit failure, UV pulse abnormal, overvoltage fault; outputs fault trip signal to generator protection system to prevent rotor winding damage caused by rectifier fault.
Description
Technical Specifications
- Rated operating power supply: 24 V DC ±10%, maximum input current 1.2 A
- Signal input channels: Multi-channel UV pulse sampling input for rectifier bridge diode monitoring
- Fault output: Relay contact trip signal, 5 A @ 250 V AC
- Operating temperature range: -20°C ~ +60°C
- Mounting standard: 40 mm DIN rail compatible rack module
- Overall dimensions: 122 mm × 80 mm × 52 mm
- Net weight: 0.32 kg
- Status indication: Power On, OVC Diode Fault, SVC Diode Fault, UV Trip LED indicators
Function Features
- Real-time sampling of rectifier bridge voltage pulse waveform, digital DSP chip analysis of diode conduction characteristics
- Independent fault judgment for positive group and negative group excitation diodes, accurate positioning of single failed diode
- Overvoltage and under-voltage pulse dual fault detection logic, covers all common rectifier bridge failure modes
- Front panel manual TEST button to trigger self-test simulation fault without generator excitation operation
- Latching fault output relay, fault state maintained until manual module power reset
- Built-in anti-high voltage surge isolation circuit, withstand rotor excitation high voltage interference
- Multi-protocol communication interface (Modbus RTU, Profibus DP) to upload fault code to upper power plant DCS system
Application Scenarios
Thermal power plant steam turbine generator excitation cabinet, hydropower station water turbine generator control system, gas turbine generator excitation rectifier monitoring, industrial large synchronous motor excitation unit, wind farm doubly-fed generator excitation fault protection.
Performance Parameters
- Fault detection response time: ≤150 ms after diode failure occurs
- High voltage isolation withstand between excitation signal input and control circuit: 2500 V AC 1 minute
- MTBF: ≥950,000 hours under power station continuous operation environment
- Pulse signal sampling frequency: 10 kHz high-speed sampling
- Electromagnetic interference immunity compliant with IEC 61000-6-2 industrial standard
Material Composition
- Module outer casing: Black aluminum alloy extrusion shell, surface oxidation anti-corrosion treatment
- Main control circuit board: High voltage resistant FR4 PCB, thick copper power traces
- Signal isolation component: High linearity pulse isolation transformer
- Indicator light housing: Transparent impact-resistant polycarbonate plastic
- Internal power filter: High temperature electrolytic capacitor + ferrite magnetic ring EMI filter
Structural Characteristics
Vertical rack plug-in module structure, front panel integrated LED status indicator group and manual test push button. Rear side multi-core terminal block for excitation pulse signal input and fault relay output wiring. Internal circuit divided into high voltage signal sampling isolation zone and low voltage DSP logic control zone with metal shielding partition to suppress high voltage excitation electromagnetic interference. Aluminum shell with heat sink fins for passive heat dissipation of power components.
Working Principle
Voltage pulse sampling cables connect the module to each arm of generator rotating rectifier bridge; isolation transformer converts high voltage excitation pulse into low voltage sampling signal transmitted to internal DSP chip. DSP collects pulse waveform, conduction angle and amplitude data of each diode in real time, compares with standard normal diode characteristic parameters stored in firmware. If one diode open-circuit or short-circuit occurs, pulse waveform distortion will be detected within 150 ms, module locks fault state, lights corresponding fault LED indicator and closes trip relay contact to send fault signal to generator protection system, triggering excitation system de-excitation protection action. Front panel TEST button simulates diode fault pulse signal to verify complete detection and trip function without generator startup.
Installation Requirements
- Install inside generator excitation control cabinet, minimum 300 mm distance from excitation transformer high voltage winding
- Signal sampling cables must use double shielded high voltage resistant twisted pair, shield layer double-end grounding at cabinet ground bus
- Module 24V DC power supply takes power from isolated control power of excitation cabinet, not shared with rotor high voltage loop
- Vertical installation required, do not mount horizontally or upside down to avoid heat accumulation
- Cabinet internal temperature controlled below 55°C; install cooling fan if long-term operation above 50°C
- All signal wiring terminals tightened with torque screwdriver at 0.6 N·m torque
Use & Maintenance Precautions
- Cut off generator excitation power and module control power before disconnecting sampling signal cables to avoid high voltage electric shock hazard
- Perform monthly manual self-test via front TEST button to confirm fault detection circuit validity
- Clean aluminum shell heat sink fins every 6 months to remove dust accumulation affecting heat dissipation
- Replace internal filter capacitors every 5 years of continuous operation to prevent capacitance aging drift
- Do not modify internal DSP firmware without official factory authorization, will cause fault misjudgment
- Avoid installing near high frequency thyristor power modules to reduce harmonic interference
- Spare modules stored in constant temperature dry cabinet, avoid damp storage leading to circuit board corrosion
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