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.

Overvoltage (59): If any phase voltage exceeds the set value and exceeds the delay, it triggers a trip.

Underfrequency (81): When the frequency is below the set point of 81T HZ and lasts for 81T TD seconds, it trips; The frequency will automatically coincide after being restored to 81R HZ for 81R TD seconds.

4. Circuit breaker monitoring and maintenance data

Trip Circuit Monitoring (TCS): Continuously detects the continuity of the trip coil through terminals 34/35. When interrupted, an alarm will be triggered and the reclosing will be locked to the "locked" state.

Circuit breaker status monitoring: Determine the validity of the circuit breaker position by verifying the consistency of the auxiliary contacts of 5a/56a.

Maintenance log: Record the number of circuit breaker operations and cumulative breaking current (I ² or accumulated value of I), providing data support for status maintenance.

Fixed value group and adaptive protection

BE1-DFPR supports up to 5 independent fixed values (Normal, Aux 1/CLP, Aux 2/EP, Aux 3, Aux 4), which can be automatically switched through external programmable inputs (USR1-USR5) or internal logic to achieve adaptive protection strategies:

Aux 1 (cold load start): Used for suppressing load surge when power is restored after a long power outage on the line. It can be automatically activated by setting the "cooling load time" and automatically switch back to the normal setting after 10 minutes.

Aux 2 (emergency operation): highest priority, used for hotline maintenance or personnel safety oriented protection settings under special working conditions, requiring external input to enable.

This design enables DFPR to dynamically adjust protection coordination based on system operating status, avoiding conflicts in setting values of traditional relays under special operating conditions.

Key points of installation and wiring engineering

1. Chassis installation

BE1-DFPR adopts a standard 19 inch rack mounted installation, with a height of 8.75 inches (5U) and a depth of 8.2 inches (behind the panel). Supporting horizontal or vertical installation, the panel opening size is shown in Figure 4-2. The maximum weight of the entire machine is 35 pounds (approximately 15.9kg), and the load-bearing capacity of the rack must be ensured during installation.

2. Wye/Delta toggle switch

The three-phase/single-phase voltage switch located behind the magnetic component panel is the most overlooked key link in on-site wiring:

For the four wire Wye wiring (phase neutral), place the switch in the Wye position.

For the three wire Delta wiring (phase to phase), place the switch in the Delta position.

After changing the switch position, it is necessary to synchronously modify the 3/1 PH WYE/DELTA setting items in "INSTALLATION SETTINGS" (1=single-phase/Wye, 2=three-phase/Delta, 3=single-phase B-phase voltage).

3. Testing plugs and uninterrupted maintenance

There is a set of standard connection plugs (optional accessories) located under the front cover of the magnetic component. After removing these plugs and replacing them with test plugs (Basler P/N 10095 or GE XLA12A), the current/voltage input and tripping/closing output circuits will be completely isolated, allowing for verification or fault simulation without the relay being powered on - this is extremely valuable for regular maintenance and upkeep of operational sites.

Communication and Debugging Access

DFPR provides front and rear dual RS-232-C ports (DB-9), with the front port automatically disabled after insertion to prevent conflicts. The communication parameters are as follows:

Baud rate: 300-19200 optional

Data bit 8, stop bit 2, no checksum

Terminal simulation: DEC VT-100 compatible

Software flow control (XON/XOFF) enabled

Through standard serial terminal software such as Windows Terminal or Procomm, all functions such as viewing and editing fixed values, downloading event records, and reading real-time measurement values can be accessed. Important safety reminder: The write life of non-volatile memory (EEPROM) is limited (about 100000 times), and frequent modification of settings through communication ports may shorten the device's service life. Unnecessary repeated write operations should be avoided.

On site testing and verification process

Chapter 5 of the manual provides detailed testing procedures, including setting value verification, action time verification, and logic function testing. The following are the core testing points:

1. Pickup Verification of Setting Values for Each Component

Overcurrent (51/50/50T): Apply single-phase or three-phase current through a three-phase relay protection tester, and confirm item by item that the deviation between the actual operating current and the set value is within the allowable range (51 is ± 2%, 50/50T is ± 5%).

Undervoltage/Overvoltage (27/59): Under the premise of applying rated voltage, slowly adjust the single-phase voltage to the set value, and confirm that the action voltage deviation is ≤ 2%.

Underfrequency (81): Apply rated voltage and adjustable frequency signal, slowly reduce the frequency to the set value of 81T HZ, confirm that the action frequency deviation is ≤ 0.01Hz; then increase the frequency to 81R HZ, confirm the automatic coincidence function.

2. Timing Verification

Apply excitation to components 51, 50, 50T, 27, 59, and 81 at twice or more of the set value, measure the time from excitation to tripping contact closure, and confirm that the error with the set curve or fixed delay is within the allowable range (51 ≤ 5%/40ms; 50T ≤ 5%/15ms; 81 ≤ 10%/50ms).

3. Verification of reclosing logic

By simulating circuit breakers (such as BE1-DFPR test simulators) to sequentially trigger tripping, verify the accuracy of the four-wheel coincidence delay, the logical response of the reset timer and maximum cycle timer, and the functional effectiveness of external lockout inputs (RCL DIS/RCL EN/DTL/RI).

4. Verification of Circuit Breaker Failure Protection (BF)

Applying fault current caused the relay to trip, but the simulated circuit breaker failed to disconnect (the current continued to exist). After confirming that the BF TD (setting range 30-500ms) timer has ended, the BFI output contact will close and the reclosing will enter the locked state.

Key points for maintenance and troubleshooting

1. Regular maintenance

Functional testing: It is recommended to conduct a complete functional test every 2 years (see Section 5 of the manual).

Clock battery replacement: The built-in lithium battery has a lifespan of about 10 years. Before replacement, please contact Basler to obtain the correct battery model and operating instructions.

Storage and maintenance: If the relay is stored for a long time, it should be powered on for 30 minutes every year to maintain the performance of the aluminum electrolytic capacitor.

2. Common troubleshooting ideas

Priority investigation direction for fault phenomena

Relay cannot start (Status LED not lit). Check the control power supply voltage and polarity to confirm if the power module is faulty

Unable to save on-site parameters to confirm if EEPROM write life is exhausted (motherboard replacement is required), or insufficient password permissions

Communication failure check whether the baud rate, data bit/stop bit/checksum settings match the terminal, and confirm the priority of the front/rear ports

27/59 component misoperation check whether the 59 setting value is lower than the 27 setting value, and whether the three-phase voltage is balanced

The reclosing lock cannot be released. Check if the TCS circuit is open or if the DTL input is continuously closed

3. Version compatibility considerations

There are differences between the manuals of Unit Revision R and subsequent versions (9231500985) and Revision Q and earlier versions (manual 9231500990). When upgrading firmware or replacing boards, it is necessary to confirm that the hardware revision matches the manual version.