Basler Electric BE1‑59N Ground Fault Relay

The Basler Electric BE1‑59N (T214750) is a solid‑state neutral overvoltage relay designed to detect ground faults in resistance‑grounded power systems. It monitors the voltage developed across the neutral grounding resistor or between the transformer neutral and ground. When a ground fault occurs, the neutral voltage rises proportionally to the fault current. The relay trips when this voltage exceeds a preset pickup level, providing sensitive protection for transformers, generators, and distribution networks.

Operating Principle

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 increases. The BE1‑59N compares this voltage to an adjustable setpoint (typically 5‑300 VAC). If the threshold is exceeded for a selected time delay (0.05‑10 seconds), the relay operates its output contacts. A built‑in filter reduces harmonics and transient noise to prevent nuisance tripping.

Adjustable Settings

Front‑panel potentiometers allow adjustment of pickup voltage and time delay. A target indicator records trip events, and a manual reset pushbutton clears the target. The relay includes a test jack for secondary injection testing, enabling functional verification without applying high voltage. Output contacts include one Form C (SPDT) rated 5 A at 250 VAC.

Technical Specifications

Input voltage: 5‑300 VAC, 50/60 Hz. Pickup accuracy: ±2% of setting. Time delay: 0.05‑10 seconds, adjustable. Output contacts: 1 SPDT, 5 A at 250 VAC. Power supply: 24‑250 VDC or 120‑240 VAC. Burden:<5 VA. Operating temperature: –20°C to +65°C. Meets IEEE C37.90 surge withstand capability.

Applications

The BE1‑59N is used on power transformers, generator neutrals, and industrial grounding systems. It is ideal for high‑resistance and low‑resistance grounded systems where sensitive ground fault detection is required. It can also be applied in ungrounded systems to detect a developing ground fault. The relay is frequently coordinated with ground fault overcurrent relays for selective tripping.

Installation and Commissioning

Mount the relay in a standard panel cutout. Connect the neutral voltage input, control power, and output contacts. Commissioning involves setting the pickup level and time delay based on system grounding parameters. Use a test set to inject a voltage signal to verify trip accuracy. The relay includes a built‑in test pushbutton for quick functional checks.

Reliability and Quality

Compliant with ANSI/IEEE C37.90 and IEC 60255, the BE1‑59N is built with high‑quality solid‑state components and conformal‑coated boards to resist humidity and contaminants. Its self‑monitoring circuits ensure reliable operation. Regular calibration is recommended but not frequently required due to the stable design.

Conclusion

The Basler Electric BE1‑59N ground fault relay (T214750) provides precise and dependable ground fault protection for critical power equipment. Its adjustable settings, robust construction, and ease of use make it a valuable asset in any protection scheme.