In every modern power system, protection relays act as the first line of defense against electrical faults. They safeguard equipment, maintain grid stability, and protect personnel by detecting anomalies and triggering fault isolation. Ensuring their accuracy is not optional—it’s essential. The Wrindu RDJB Series Microcomputer Protection Relay Tester brings laboratory-grade precision into a compact, field-ready design, empowering power engineers to perform comprehensive relay calibration and testing with unmatched reliability and efficiency.
The Role of Relay Testing in Power Systems
Protective relays are the “decision-makers” of electrical networks. They detect irregularities—such as short circuits, overloads, or abnormal frequency—and command switching devices to operate. Failure of even one relay can lead to severe outages or equipment damage.
This makes relay testing a core process in maintenance and commissioning. By simulating real-world faults under controlled conditions, engineers can verify that each protective device operates at the correct threshold and time delay.
The RDJB Series, developed by Wrindu, simplifies this vital task by combining advanced DSP-based test generation, flexible operation modes, and automated test sequences into one intelligent and portable platform.
Technical Overview of the RDJB Series
The RDJB Series, available in models RDJB-802M and RDJB-1600M, integrates leading microelectronic and control technology. Each unit merges high-output capability with precise real-time signal processing—providing up to six voltage and current phases for simultaneous or independent testing.
It features an open architecture running on Windows OS, allowing standalone use or PC-controlled automation, ensuring adaptability for laboratory and field conditions alike.
Table 1. Key Technical Highlights
| Specification | RDJB-802M / RDJB-1600M |
|---|---|
| AC Current Output | Up to 30 A per phase / 180 A total (six-phase parallel) |
| AC Voltage Output | 0–120 V (per phase); line voltage up to 240 V |
| Frequency Range | 0–1000 Hz (2–20th harmonics supported) |
| DC Voltage Range | ±160 V per phase / ±320 V line |
| DC Current Range | ±10 A per phase |
| Output Accuracy | Voltage : 0.2 grade |
| Timing Measurement Accuracy | RDJB-1600M < 0.1 ms; RDJB-802M = 1 ms |
| Power Supply | AC 220 V ± 10%, 50 Hz |
| Communication | USB interface for PC and external device connection |
Advanced Functional Features
1. Multi-Phase and Multi-Function Output
The RDJB tester supports up to six simultaneous outputs of current and voltage, enabling testing of complex protection systems such as differential relay schemes and multi-zone synchronizing circuits. It can reproduce a variety of fault conditions—including three-phase short circuits and ground faults—with precision in amplitude, phase, and frequency.
2. High-Fidelity Signal Generation
Using modular linear amplifiers, the test system produces clean, distortion-free waveforms. Engineers can simulate real power system transients—harmonics, phase shifts, and waveform distortions—to observe exact relay responses.
3. DSP-Controlled Precision
The Digital Signal Processor (DSP) performs real-time waveform synthesis and correction, ensuring frequency stability and phase accuracy even at abrupt load changes.
4. Comprehensive Software Platform
The built-in application suite supports:
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Automatic calibration and fault record replay
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Setting verification of overcurrent and voltage thresholds
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Timing and trip characteristic measurement
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Test report generation and storage via USB or local memory
5. Safety & Durability by Design
Efficient heat dissipation, short-circuit protection, and overload detection protect both the instrument and the tested relay. Its lightweight structure ensures easy field deployment, while maintaining lab-grade performance.
Working Principle and Test Execution
Relay testing with the RDJB series follows three precise stages:
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Simulation: The device generates accurate AC or DC test signals corresponding to real power system parameters (voltage, current, and phase).
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Monitoring: The system observes how the relay reacts—its trip signal, timing, and contact status—through multiple input channels.
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Verification: Results are analyzed and compared to expected values to confirm calibration accuracy and relay performance.
Because of its multi-phase design, engineers can simultaneously evaluate several relay operations in a single test sequence, significantly improving efficiency in large-scale maintenance activities.
Comparison of Model Capabilities
Table 2. RDJB-802M vs RDJB-1600M Quick Comparison
| Parameter | RDJB-802M | RDJB-1600M |
|---|---|---|
| Timing Accuracy | 1 ms | < 0.1 ms |
| Parallel Current Power | 800 VA | 1000 VA |
| Output Flexibility | 3 – 6 phases | 6 phases (max) |
| Ideal Application | Portable calibration | Advanced laboratory testing |
Wrindu Expert Views
“Protective relays are the heartbeat of electrical safety systems—one second of delay can mean catastrophic damage.
Our RDJB Series was engineered to combine flexibility and accuracy within one instrument. By utilizing digital signal processing and multi-phase control, Wrindu has achieved the perfect balance of compactness, power, and performance. This allows protection technicians to carry laboratory-level testing capability directly to remote substations, ensuring operational assurance across entire power networks.”
— Chief Engineer, Wrindu Power System Testing Division
Application Scenarios
The RDJB Series is used widely in:
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Power utilities and substations for periodic relay calibration.
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Transformer and circuit-breaker manufacturers verifying new protection systems.
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Industrial automation facilities for motor and feeder protection verification.
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Research institutions conducting high-precision relay characteristic studies.
With its dual operation mode and automated report export, engineers can perform on-site diagnosis and documentation in real time, reducing downtime and enhancing reliability.
Advantages of Wrindu’s Design
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High performance, portable size: Compact form factor with laboratory precision.
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Versatile testing: Differential, synchronizing, reclosing, and fault simulation.
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Long-term durability: Rigid hardware with heat and overload protection.
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Intuitive interface: Built-in Windows control or PC automation for convenience.
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Global compliance: CE certification and adherence to EN safety standards.
Wrindu’s commitment to research, innovation, and user-focused engineering ensures that each model serves as a trusted partner for relay technicians worldwide.
Conclusion: Precision You Can Rely On
In a field where milliseconds matter and accuracy safeguards millions in infrastructure, the Wrindu RDJB Series Microcomputer Protection Relay Tester stands as an indispensable tool for ensuring grid resilience. Its powerful multi-phase capability, real-time DSP control, and user-friendly software redefine how relay testing is performed—bridging reliability, functionality, and technological excellence.
Key Takeaways:
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Multi-phase control ensures comprehensive simulation for all relay types.
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DSP technology delivers stable, distortion-free testing output.
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Portable design meets both field and laboratory demands.
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Wrindu continues to advance intelligent testing for a safer, smarter power grid.
FAQs
1. What types of relays can the RDJB series test?
It supports electromagnetic, static, and digital relays, covering applications such as overcurrent, voltage, distance, differential, and frequency protection.
2. Can the tester reproduce harmonic and transient waveforms?
Yes. It generates harmonics up to the 20th order and can simulate transient disturbances for dynamic relay verification.
3. How precise is the RDJB timing measurement?
Depending on the model, timing accuracy ranges from 1 ms (RDJB-802M) to < 0.1 ms (RDJB-1600M).
4. Is the system suitable for field use?
Absolutely. With its lightweight body, built-in heat protection, and Windows-based standalone operation, it’s ideal for mobile or substation testing.
5. How does Wrindu ensure equipment reliability?
Each tester undergoes ISO and IEC compliance checks, integrating hardware protection, calibration validation, and international CE certification for quality assurance.