Basler Electric BE1‑59N Ground Fault Overvoltage Relay

The Basler Electric BE1‑59N is a sensitive solid‑state relay that detects overvoltage on the neutral point of grounded AC systems. It is primarily used to sense ground faults in resistance‑grounded or ungrounded systems, where a fault produces a displacement of the neutral voltage. When the neutral‑to‑ground voltage exceeds the adjustable pickup setting, the relay initiates a trip or alarm, helping to isolate the faulty circuit and prevent equipment damage.

Principle of Operation

The relay measures the RMS voltage between the system neutral and ground. Under normal conditions, this voltage is near zero. During a ground fault, the neutral voltage rises in proportion to the fault current and the grounding impedance. The BE1‑59N compares this voltage to a setpoint (e.g., 5‑300 V). If the threshold is exceeded for a selected time delay, the relay output changes state. A built‑in filter reduces harmonics and transient noise for stable operation.

Adjustable Parameters

Pickup voltage: adjustable over a wide range via front‑panel potentiometer. Time delay: selectable from 0.05 to 10 seconds using DIP switches. The relay also features a dropout ratio of approximately 95% to prevent chattering near the pickup point. A target indicator records the trip event.

Technical Specifications

Input: 5‑300 VAC, 50/60 Hz. Accuracy: ±2% of setting. Time delay accuracy: ±3% or 50 ms. Output: 1 Form C, 5 A at 250 VAC. Power supply: 24‑250 VDC or 120‑240 VAC. Operating temperature: –20°C to +65°C. Enclosure: metal, panel‑mount. Meets IEEE C37.90 surge withstand.

Applications

This relay is widely used in transformer neutral protection, generator grounding, and industrial distribution systems. It is particularly effective in detecting high‑impedance ground faults that may not be detected by overcurrent relays alone. It can also serve as a backup for ground fault protection schemes.

Installation and Testing

Install the relay in a panel with proper clearances. Connect the neutral sensing lead and control power. Commissioning involves setting the pickup and time delay, then performing a secondary injection test to confirm operation. The relay has a built‑in test pushbutton for quick verification.

Reliability and Quality

Basler Electric’s BE1‑59N is built with solid‑state technology, offering high reliability and long life. It is fully sealed and resistant to dust and humidity. Each unit is factory calibrated and tested to ensure consistent performance.

Conclusion

The Basler Electric BE1‑59N ground fault overvoltage relay is a trusted, accurate, and easy‑to‑use solution for neutral overvoltage protection. Its sensitivity and versatility make it an essential component in modern power system protection.