Basler Electric PRS250 Veri‑Sync Relay

The Basler Electric PRS250 (part number 9088800102) is a precision solid‑state synchronism‑checking relay that provides a permissive output for circuit breaker closure only when the two AC sources are within preset limits of voltage magnitude, phase angle, and slip frequency. This relay is essential for generator paralleling, bus‑tie transfer, and utility interconnections to prevent out‑of‑phase closure, which can cause severe mechanical and electrical damage. The PRS250 is widely recognized for its accuracy, stability, and ease of configuration.

Adjustable Windows and Dwell Time

The relay independently measures the voltage difference, phase angle difference, and slip frequency between the two sources. Each parameter has an independent adjustable window: voltage match from 5% to 20% of nominal, phase angle from 1 to 20 degrees, and slip frequency from 0.05 to 0.5 Hz. A programmable dwell timer (0.1 to 10 seconds) ensures that the conditions remain stable before the permissive output is issued. A voltage‑matching output is provided to fine‑tune the generator AVR for faster synchronization.

User Interface and Diagnostics

The front panel includes LED indicators for source availability, synchronism status, and relay health. DIP switches and potentiometers allow easy setting adjustments without external software. A test pushbutton permits functional verification, and a reset button clears the target. The relay offers one Form C output contact (rated 5 A at 250 VAC) for breaker control. The unit is housed in a rugged metal enclosure for standard panel mounting.

Technical Specifications

Input voltage: 100‑480 VAC, 50/60 Hz (single‑phase or three‑phase sensing). Accuracy: ±2% for voltage, ±1 degree for phase angle. Output contact: 1 Form C, 5 A at 250 VAC. Power supply: 24‑250 VDC or 120‑240 VAC. Burden:<5 VA. Operating temperature: –20°C to +65°C. Compliance with IEEE C37.90 surge withstand and CE marking.

Applications

The PRS250 is used in emergency generator sets, marine power systems, co‑generation plants, and automatic transfer switches. It ensures safe paralleling of generators with the utility grid or with each other, preventing damage to prime movers and generators. It is also employed in bus sectionalizing and tie‑breaker control schemes.

Installation and Commissioning

Mount the relay in a panel cutout. Connect the voltage inputs from both sources (line and bus). Wire the output to the breaker close circuit. Commissioning involves setting the windows and dwell time, then verifying with a synchronizing test set. The relay includes a simulation mode for testing without live voltages.

Reliability and Quality

Basler Electric ensures high reliability through rigorous component selection and environmental testing. The solid‑state design minimizes maintenance and extends service life. The relay is backed by Basler’s technical support and comprehensive documentation.

Conclusion

The Basler Electric PRS250 Veri‑Sync relay (9088800102) is a trusted solution for synchronism verification, combining precision, flexibility, and robust construction to safeguard power system paralleling operations.