Basler BE1-DFPR feeder protection relay

Basler BE1-DFPR Distribution Feedline Protection Relay: Technical Architecture and Application Details

Product positioning and model identification

BE1-DFPR (Distribution Feeder Protection Relay) is a microprocessor based multifunctional feeder protection relay suitable for comprehensive protection, monitoring, and control of radial distribution lines. The core design concept is to integrate the scattered overcurrent relays, reclosing devices, voltage monitors, and instrument functions in traditional distribution stations into a 19 inch standard chassis, greatly saving cabinet space and simplifying wiring.

The product model defines electrical characteristics and functional options through a structured model code (Style Number). Taking 5 A2 V F T H A as an example:

Meaning of code location

5 CT secondary side rated value: 5A (optional 1A)

A2 dual power supply: 125Vdc or 120Vac (A1 is a single power supply)

Under voltage protection function (27 components)

F underfrequency protection function (81 components)

T Control Input Test Module (optional)

H horizontal installation method (V is vertical installation)

RS-232-C terminal communication

Engineering Tip: When purchasing spare parts or modifying systems, it is essential to verify the complete model code on the label behind the relay to ensure that the functional configuration is consistent with the system requirements. There are differences in hardware and communication protocols between different revision versions (Unit Revision R and subsequent), and a separate manual (9231500990) is required for Revision Q and earlier versions.

Technical specifications and performance parameters

1. Communication input

Current input: When the 5A CT range is used, it can continuously carry 20A and withstand 500A heat for 1 second; when the 1A CT range is used, it corresponds to 4A/100A. Each phase and neutral line current input is independent.

Voltage input: Supports phase to phase voltages of 100V, 173V, 192V (50Hz) or 120V, 208V, 230V (60Hz). The continuous overload capacity is 133% of the rated value, and the 1-second withstand voltage can reach 260V (50Hz)/320V (60Hz).

Frequency response: The effective range is 40-55Hz in 50Hz mode and 50-65Hz in 60Hz mode, with suppression of secondary and higher harmonics ≥ 12dB.

2. Protection of component accuracy

Time limited overcurrent (51/51N): Setting range 0.5-12A (5A CT, step size 0.1A), accuracy ± 2% or 50mA. 12 types of inverse time limit curves are available (including BS142 standard curve), with timing accuracy ≤ 5% or 40ms.

Instantaneous overcurrent (50/50N): Setting range 0.5-150A (5A CT), accuracy ± 5%, action time characteristics are shown in Figure 1-3 (manual).

Timed speed limit cutoff (50T/50TN): Delay of 30-5000ms can be set, with an accuracy of ± 5% or 15ms.

Undervoltage (27): Setting range 50-120V, delay 1-1000s, accuracy ± 2%.

Overvoltage (59): Setting range 50-150V, delay 0-100s (0 is prohibited), accuracy ± 2%. Attention: The setting value of 59 should not be lower than the setting value of 27, otherwise the relay will mistakenly send a trip signal.

Underfrequency (81): Setting range rated frequency -10Hz to+5Hz, resolution 0.01Hz, delay 100-500ms. Recovery frequency can be independently set (1-1000s).

3. Control the power supply and contact capacity

The control power supply can be selected as 48Vdc, 125Vdc or 120Vac, with dual power redundancy configuration (the second digit of the model code is A2/B2/C2).

Trip contact capacity: 30A for 0.2 seconds (meets ANSI C37.90), continuous current carrying 3A, arc breaking capacity 0.3A @ 250Vdc (L/R=0.04).

Functional architecture and protection logic

The functional architecture of BE1-DFPR can be divided into four modules: protection, control, data processing, and communication.

1. Three level coordination of overcurrent protection

DFPR provides three layers of overcurrent protection for each phase and neutral line:

Time overcurrent (51): Used for fault main protection, 12 types of inverse time curves can be selected, and the "integration to reset" feature is used to achieve a heat dissipation memory effect similar to traditional electromechanical relays.

Instantaneous overcurrent (50): used to quickly clear severe faults in the near area, with an action time of less than 1.5 cycles.

Timed speed limit breaking (50T): used to achieve zone sequence coordination with downstream fuses or reclosers, identifying downstream faults that have been cleared through low setting instantaneous components, thereby avoiding unnecessary tripping upstream.

2. Automatic reclosing (79)

Built in 4 reclosing logic, each reclosing delay is independently adjustable (0.04-100s for the first reclosing and 0.04-200s for the second to fourth reclosing). Combined with the maximum cycle timer (0-999s) and the coincidence failure timer (0-9.9s), it can prevent the circuit breaker from reversing and tripping due to permanent faults. The external input terminals (RI/RDS/REN/DTL) support remote or local switching on/off and re closing functions.

3. Voltage and frequency protection

Undervoltage (27): If the voltage of any phase is lower than the set value and exceeds the delay, a trip will be triggered. Return time ≤ 16ms.