87b is a low-priced relay protection tester

The BE1-87B is an economical high-speed bus differential relay, designed for reliable protection rather than being a low-cost tester.

Overview

The BE1-87B is a high-impedance bus differential relay used for protecting high-voltage and critical bus systems. It provides fast fault detection, typically operating in less than 7 milliseconds for moderate fault levels and under 5. 5 milliseconds for higher fault currents, minimizing potential damage to equipment (ManualsLib).

Its design supports single-phase, three-phase, and rack-mounted configurations, offering flexibility for various installations (pdf4pro).

Key Features

High Impedance Differential Protection: Detects unbalances between currents entering and leaving a bus, ensuring selective and reliable fault detection (pdf4pro).

C

T Circuit Diagnostics: Monitors current transformer (CT) connections to prevent misoperation due to wiring errors or shorted CTs (pdf4pro). Testable Drawout Design: Allows safe testing and maintenance without removing the relay from the panel (pdf4pro).

Alarm and LE

D Indicators: Provides visual alerts for CT overvoltage or abnormal unbalance conditions (pdf4pro). Durability and Standards Compliance: Withstands 300 Vac for up to 60 minutes and meets IEC 255-21-1 Class 1 standards (ManualsLib).

Cost Considerations

While the BE1-87B is described as economical for high-speed protection applications, it is primarily a protection relay rather than a low-cost relay tester. Its pricing is generally lower than some advanced digital bus protection systems but is not necessarily “low-priced” in absolute terms, as it is designed for critical power system reliability (pdf4pro). The term “economical” refers to its balance of performance, reliability, and cost-effectiveness for high-impedance bus differential applications.

Conclusion

The BE1-87B is a reliable, high-speed bus differential relay with diagnostic and test features that make it suitable for critical power systems. It is economical relative to its protection capabilities, but it is not a simple low-cost relay tester. Its value lies in robust protection, fast fault response, and diagnostic functionality, making it a practical choice for high-voltage bus protection applications (Basler Electric).