Beckwith M-3310 Transformer Protection Relay Complete Guide

Data can be accessed through a dedicated IPSlot ®  PLUS software analysis, or conversion to COMTRADE standard format through ComVert tool for easy interaction with third-party tools.

6.2 Event Recording

It can store 32 recent events (targets), including action functions, picking, input/output status, timestamps, and current values of each phase during tripping.

6.3 Real time measurement

Measurement parameters include voltage, current, power factor, active/reactive/apparent power, frequency, demand (15/30/60 minute sliding), and maximum value (with time stamp).

Accuracy: Current ± 0.1A or ± 3% (5A rated), voltage ± 0.5V or ± 0.5%, power ± 0.01PU or ± 2%, frequency ± 0.02Hz.

Communication and time synchronization

Communication ports: Front panel RS-232 (for local debugging), rear panel RS-232 and RS-485 (can connect 2 or 4 wires), supporting Modbus RTU and BECO 2200 proprietary protocols.

PC software: M-3820A IPScom ®  Used for parameter reading and writing, real-time monitoring, and firmware upgrades.

IRIG-B synchronization: accepts modulated or demodulated IRIG-B signals, providing high-precision time labels for events and recording.

Key points for installation and debugging

Rack installation: Standard 19 inch cabinet can be installed horizontally or vertically (optional mounting rack is required). The opening size is shown in Figure 4/5.

CT polarity: Differential protection requires that the CT polarity directions on both sides be consistent (both pointing towards the transformer), and must be confirmed according to the typical wiring diagram in Figure 2/3.

CT ratio compensation: By adjusting the CT Tap parameters, the balanced current of the differential circuit is made to approach zero at rated load.

Harmonic blocking test: Before powering on, a relay protection tester can be used to apply a current containing second harmonic to verify whether the differential is reliably blocked.

Circuit breaker status input: INPUT1 needs to be connected to contact 52b (closed when the circuit breaker is open) to ensure that the BRKR CLOSED LED and logic on the front panel are correct.

Output contact testing: Verify the mapping relationship between the protection functions corresponding to each output, ensuring that the tripping matrix is correct (for example, tripping both the high and low voltage side circuit breakers simultaneously after the 87T action).

Fixed value group switching verification: If multiple fixed values are used, external contacts or communication should be used to switch and verify the current activated group.

Environment and Certification

Working temperature: -20 ℃~+70 ℃ (storage -40 ℃~+70 ℃), humidity 93% RH@40 ℃.

Electromagnetic compatibility: through IEC 1000-4-2 electrostatic discharge (8kV), IEC 1000-4-4 fast transient (4kV), IEEE C37.90.1 oscillating wave/fast transient (2.5kV/5kV) and radiation immunity (35V/m).

Insulation withstand voltage: All circuits to ground 3500V DC/1min, RS-485/RIG-B to ground 1500V DC.

Certification: cULus Listed (UL 508 and CSA C22.2), suitable for industrial control equipment and control cabinets.

Common engineering application extensions

Load Shedding: Utilizing the undervoltage (27) function in the voltage protection package, in conjunction with external output contacts, to quickly cut off secondary loads when the bus voltage drops, preventing transformer overload.

Bus Fault Protection: Combining the logic of M-3310 and feeder digital relays, it receives feeder protection action signals through external inputs to achieve rapid isolation of faults within the bus area.

LTC fault lockout: When an internal fault is detected, the on load tap changer operation is locked to prevent the fault from expanding.

Cooperate with automatic backup power input (BZT): Utilize circuit breaker failure and low-frequency protection to quickly activate the backup power input logic after the transformer trips.

Maintenance and fault diagnosis

Self check function: The device continuously performs software and hardware self checks. If any abnormalities are found, the SELF-TEST ALARM contact will activate and the RELAY OK LED on the front panel will turn off.

Target reset: Press the TARGET RESET key to reset the target LED (if the fault has disappeared); Long press to view the protective components currently in the picking state.

Wave recording analysis: For tripping accidents, the wave recording file should be downloaded and IPSpot should be used to analyze the differential current waveform, distinguishing between faults within the area and non fault disturbances such as excitation inrush current and CT saturation.

Firmware upgrade: Use IPScom software to upgrade through the RS-232 port on the front panel, and be sure to save the original settings file.