Basler BE1-51 Time Overcurrent Relay Debugging Guide

Detailed explanation of overcurrent characteristic curve

The core technological value of BE1-51 lies in its rich temporal characteristic library. According to different timing options, the available characteristic curves can be divided into three categories:

4.1 Non integral timing (Z1, Z2 options)

B1~B7: Seven standard inverse time curves: short inverse time limit, long inverse time limit, definite time limit, medium inverse time limit, inverse time limit, even inverse time limit, and extreme inverse time limit

B8: I ² t curve

C1~C8: I ² t with limit range 1~8 (Z1 option only)

E2/E4/E5/E6/E7: BS142 standard curve (Z2 option only), including long inverse time, inverse time, very inverse time, and extreme inverse time

4.2 Integral timing (Z3 option)

The Z3 option uses an integral algorithm to simulate the operating characteristics of an electromagnetic overcurrent relay. Its timing curve corresponds one-to-one with the Z1/Z2 standard curve, but is implemented through time incremental accumulation - it only acts when the accumulated "energy" during the overcurrent duration reaches the preset threshold. This characteristic is closer to the thermal memory effect of traditional electromechanical relays.

4.3 Extended Timing

When selecting the 2-D or 2-E option, the standard delay is multiplied by approximately 5.7 times, which is suitable for cascading protection scenarios that require longer delay coordination.

All curves can be interpolated and selected from the 100 possible curves in each curve chart using the TIME DIAL (00~99) on the front panel. Appendix A shows the trends of each characteristic family with 14 representative curves. Users can switch between up to 16 types of curves through the 16 bit selector switch on the internal circuit board on the right.

Installation and wiring points

BE1-51 adopts the standard S1 chassis size. Attention should be paid during installation:

The grounding terminal at the rear of the chassis must be hard grounded to the ground with a copper wire of not less than 12 AWG

When unplugging the connection plug (1 10 terminal chassis, 2 20 terminal chassis), disconnect the normally open trip circuit first, short-circuit the normally closed circuit first, and then disconnect the power supply and induction circuit to ensure that the CT does not open circuit

The external trip circuit must be disconnected through the 52a contact to prevent inductive overload of the relay contacts

Wiring wire not less than 14 AWG

For equipment that is stored for a long time (as a backup) and contains long-life aluminum electrolytic capacitors, it is recommended to run the capacitor on power for 30 minutes every year to extend its lifespan.

Complete process of on-site testing and calibration

6.1 Test Preparation

Required equipment: Suitable AC/DC power supply, 50/60Hz current source, DC external power supply (for output circuit and timer input), relay protection tester capable of outputting 40A or more, timer, shunt resistor (to provide minimum load current for the target). Connect the test circuit according to the induction input type (K single-phase, G three-phase, H/V three-phase with neutral wire, I/X two-phase with neutral wire) as shown in Figure 5-1~5-4 of the manual.

6.2 Time overcurrent startup test

Set TIME DIAL to 99, INST 1/2 to maximum (clockwise), TAP CAL to maximum (clockwise)

Select A gear for TAP and slowly increase the current until the TIMING indicator light is just on (first adjust CAL counterclockwise until the light is on, then clockwise to the maximum, and then increase the current until the light is on)

Record the starting current value (should be within ± 5% of the TAP A value)

TAP selects J gear for repeated testing and records the maximum starting point (which should be within ± 5% of the J gear value)

Repeat the above steps for each phase and neutral wire model of multiphase/neutral wire

6.3 Timing output accuracy test

TAP selects B mode, TIME DIAL is set to 20

Apply an overcurrent of 5 times the precise TAP B value and start the timer

Find the intersection point between the 5-fold point on the corresponding characteristic curve and the TIME DIAL=20 curve, and read the theoretical delay

The actual timing reading should be within ± 5% of the theoretical value

Time DIAL is set to 40, 60, and 99 for repeated testing

For models with neutral wires, the test signal should be connected to the neutral wire input terminals (17, 18) and the above steps should be repeated

6.4 Transient Overcurrent Start Test

INST 1 is adjusted to the minimum (counterclockwise), corresponding to a startup value of 1 times the TAP A gear value

Slowly increase the current to the output relay of INST 1 and record the current (should be ≤ TAP A value)

INST 1 is adjusted to maximum (clockwise), corresponding to a startup value of 40 times the TAP A gear value

Slowly increase the current from 35 times to the relay action, and record the current (should be>40 times the TAP A value)

Repeat the test on neutral line INST 1 (if any) and INST 2 (if any)

6.5 On site precise calibration steps

If the target startup value falls between the TAP gears, or if the device is equipped with an instantaneous overcurrent option, it is recommended to calibrate accurately on the test bench according to the following steps: