Basler BE1-32R/32O/U Direction Power Relay Setting and Testing Guide

Guidelines for Setting and Testing Basler BE1-32R/32O/U Direction Power Relays

In power plants, industrial self owned power stations, and new energy grid connected systems, directional power relays are key protective devices to prevent damage to the prime mover and avoid system reverse power accidents. The Basler BE1-32R (over power/reverse power) and BE1-32O/U (over power+under power) series solid-state relays, with their wide range tuning, high precision, and flexible time curves, have long served steam turbines, water turbines, diesel generators, and grid interconnection nodes. However, on-site engineers often face problems such as confusion in model selection, mismatch between setting parameters and operating conditions, and unfamiliarity with testing methods. This article is based on the complete technical manual of this series of relays, systematically sorting out its core functions, setting logic, testing verification, and typical fault response from the perspective of engineering application, helping maintenance personnel quickly grasp the essentials of using this protection device.

Product positioning and model identification

BE1-32R is a directional over power relay that can detect excessive power flow along the "trip direction", typically used for generator reverse power protection (reverse power transmission). BE1-32O/U integrates both over power and under power detection functions, suitable for applications that require simultaneous monitoring of power upper and lower limits, such as start stop control in combined power generation systems or load monitoring of interconnected lines.

Model recognition relies on the "Style Number" code on the panel, which consists of multiple digits and letters, respectively defining:

Sensor input type (A/B/C/D/E/V, corresponding to single-phase/three-phase, phase voltage/line voltage combination)

Rated frequency (50/60 Hz)

Output contact form (normally open/normally closed)

Time characteristics (instantaneous, timed, inverse time)

Auxiliary contact and target indicator options

Engineers must verify the CT/PT polarity, phase rotation, and required time curve of the original system when replacing old relays or building new projects, otherwise it may result in misoperation or refusal to operate.

Typical application scenarios and tuning logic

2.1 Generator reverse power protection (reverse electric operation)

When the steam turbine loses its original power (such as when the main steam valve is closed), the generator remains tied to the power grid and will operate as an electric motor, absorbing active power from the system to drive the rotor. This' reverse power 'state is particularly dangerous for steam turbines - the lack of steam cooling can cause blade overheating and deformation. The manual provides the reverse power tolerance threshold for different prime movers:

Water turbine: 0.2%~2.0% of rated kW

Steam turbine (condensing or back pressure): 0.5%~3.0%

Diesel engine (no combustion): up to 25%

Gas turbine: up to 50% (due to compressor losses)

During actual tuning, the over power (reverse) starting value of BE1-32R is usually set as low as possible, with steam turbines generally not exceeding 3% and diesel/gas turbines not exceeding 10%. To avoid misoperation caused by transient impact during grid connection, it is necessary to cooperate with a fixed time delay (typically 2-10 seconds, or even more than 30 seconds). The manual clearly states that this relay is not suitable when the power factor is below 0.10, and the manufacturer needs to be contacted for a specialized solution.

2.2 Cogen Start Stop Control

In the cogeneration system, BE1-32O/U can simultaneously achieve "start" and "stop" signals:

Start logic: Monitor the input power of the mains power. When the power exceeds the set value (such as excessive mains load), the over power output is closed, triggering the automatic start and networking of the backup generator.

Shutdown logic: When the generator takes on the load, the mains power decreases; When the mains power is lower than a certain threshold (such as set to 50% of the overcurrent setting value), the low-power unit outputs a shutdown signal after delay, causing the generator to stop running.

This application requires precise setting of the underpower percentage (adjustable from 10% to 95%) and sufficient delay (several minutes) to avoid frequent start stop caused by load fluctuations.

2.3 Circuit breaker tripping detection and interconnection line protection

In industrial power distribution, multiple incoming lines come from the same substation, or there is a local power source connected in parallel with the mains power. When one of the circuit breakers accidentally disconnects, it may cause overload or unexpected power flow in the remaining lines. BE1-32 relay can detect changes in power direction:

During normal operation, the power direction is located in the first and second quadrants (positive or reactive power flow).

When a certain circuit is disconnected, the local generator sends electricity back to the grid, and the power direction shifts to the third or fourth quadrant. At this time, the relay acts and trips the corresponding circuit breaker.