Basler Electric PRS250 Veri‑Sync Relay

The Basler Electric PRS250 (part number 9088800102) is a solid‑state synchronism‑checking relay that ensures two AC sources are within acceptable limits of voltage magnitude, phase angle, and slip frequency before permitting breaker closure. This relay is essential for generator paralleling, bus tie transfer, and co‑generation applications where out‑of‑phase closure could cause catastrophic mechanical and electrical damage.

Measurement and Settings

The PRS250 monitors both sources and compares their voltage, phase difference, and frequency difference. Each parameter has an independent adjustable window: voltage match typically 5‑20% of nominal, phase angle 1‑20 degrees, and slip frequency 0.05‑0.5 Hz. When all conditions are satisfied for a programmable dwell time (0.1‑10 seconds), the relay closes its output contact. A voltage‑matching output can be used to adjust the generator AVR to reduce phase error.

Design and Interfaces

The relay features a front panel with LED indicators for source presence, synchronism status, and health. DIP switches and potentiometers allow easy setting adjustments without external software. It includes one Form C output contact (rated 5 A at 250 VAC), a test pushbutton, and a manual reset. The relay is housed in a rugged metal enclosure suitable for 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. 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. Meets IEEE C37.90 surge withstand capability.

Applications

The PRS250 is widely used in emergency generators, marine propulsion systems, utility interconnections, and industrial co‑generation. It is also employed in automatic transfer switch schemes to ensure safe re‑transfer of loads. The relay can be used with both synchronous and induction generators (with appropriate settings).

Installation and Commissioning

Mount the relay in a standard panel cutout. Connect the voltage inputs from both sources (line and bus), and the output to the breaker close coil circuit. Commissioning involves setting the voltage, phase, and slip windows according to system requirements, then testing with a synchronizing test set. The relay includes a built‑in simulation mode for functional verification.

Reliability and Quality

Basler Electric’s PRS250 is built with high‑reliability components and subjected to rigorous environmental and electrical testing. Its solid‑state design ensures long life and minimal maintenance. The relay is backed by Basler’s technical support and documentation.

Conclusion

The Basler Electric PRS250 Veri‑Sync relay (9088800102) is a dependable, accurate, and easy‑to‑configure synchronism‑checking device that enhances safety and reliability in power system paralleling operations.