Debugging and Testing of Basler BE1-700 Relay

Guide for On site Debugging and Functional Verification of Basler BE1-700 Digital Voltage Protection Relay

Abnormal voltage and frequency are common causes of equipment damage or system instability in power generation, distribution, and industrial power systems. The BE1-700 from Basler Electric is a digital multifunctional relay designed specifically for voltage protection. It integrates protection functions such as overvoltage, undervoltage, negative sequence overvoltage, overexcitation (V/Hz), frequency and synchronization detection, and is equipped with programmable logic, fault recording, and event recording capabilities. Its compact chassis and flexible communication interface make it an ideal choice for retrofitting old systems and building new equipment. This article is based on the technical manual of the relay, systematically sorting out its installation configuration, protection function setting, BESTCOMSPlus software operation, and on-site testing methods from the perspective of engineering application, providing a practical operation guide for relay protection engineers.

Product positioning and hardware version identification

BE1-700 is a pure voltage type digital protection relay (without current input), suitable for scenarios such as busbars, transformers, generators, incoming lines, and feeders that require voltage and frequency monitoring. It provides three-phase voltage input and one auxiliary voltage input, supports three-phase three wire or three-phase four wire wiring, and has IRIG-B clock synchronization, USB-C front-end port, and optional Ethernet communication.

Hardware version differentiation: The manual clearly states that the front panel communication port of hardware version 4 (current version) is USB-C, while the old versions (1-3) are RS-232. In terms of voltage/current input, the old version can choose voltage or current, while version 4 only has voltage input. The software package has also been upgraded to BESTCOMSPlus (replacing the old version of BESTCOMS). When selecting, it is necessary to confirm the version. The new firmware supports communication through both Modbus TCP and BESTCOMSPlus, and the Modbus protocol can be selected as Ethernet or RS-485 (user configurable).

Installation wiring and grounding specifications

BE1-700 adopts a fixed panel mounted chassis (non drawer type) with compact size (see manual size diagram). There is no need for vertical restriction during installation, any angle is acceptable, but the direction of the HMI display screen is fixed.

Key points of electrical wiring:

Voltage input: Three phase voltage is connected to terminals C13 (VA), C14 (VB), C15 (VC), and C16 (neutral point N). Auxiliary voltage Vx connected to C17 (polarity) C18。 Rated continuous voltage: three-phase 300V line, auxiliary 150V line.

Control power supply: connect A6 and A7, voltage range depends on the model (24/48/125/250 Vdc or 120/240 Vac), no polarity. When the power supply is normal, the green Power LED on the front panel lights up.

Contact input (IN1~IN4): Connect B1/B2, B3/B4, B5/B6, B7/B8, requiring external wet voltage (ranging from 5~200V depending on the model), polarity sensitive, pay attention to positive and negative.

Output contacts (OUT1~OUT5 and OUTA): OUT1~OUT5 are normally open (Form A), and OUTA is fail safe normally closed (power-off closed). Contact capacity: 30A/0.2s closing, 7A continuous, 0.3A disconnection (inductive).

Grounding: A copper wire of not less than 12 AWG must be used to connect to the grounding terminal of the enclosure, and it is recommended to independently lead to the grounding grid. EMI suppression: If the output drive coil is connected in parallel with a reverse diode at the coil end.

Insulation test warning: External wiring must be disconnected before conducting voltage withstand test, otherwise internal components may be damaged.

Software installation and initial connection

BE1-700 is configured and monitored through BESTCOMSPlus software. This software is based on NET Framework， Windows 7 SP1 and above systems are required, and 2GB of memory is recommended. Do not connect the USB cable before installation, otherwise it may cause the driver installation to fail. Download the installation package from the Basler official website, and the installation process will automatically install the USB driver and BE1-700 plugin.

Connection steps:

After installation, connect the PC to the front panel port of the relay using a USB-C cable, and then power on the relay.

Start BESTCOMSPlus, select the language, click on "New Connection" to choose BE1-700, then select USB Connection and Connect.

After successful connection, read the current settings and logic through "Download Settings and Logic from Device" for modification or backup.

Basic system parameter settings

Firstly, configure the nominal values of the system, which affect the baseline of all protection functions.

In BESTCOMSPlus, navigate to Settings Explorer → System Parameters → Power System:

Nominal Frequency: 50 or 60 Hz.

Nominal Phase Rotation: ABC or ACB (affecting negative sequence calculation).

Nominal Voltage: The equivalent voltage between the secondary side phase and neutral. For example, if the PT secondary line voltage is 120V (three-phase three wire), then the input here should be 120/√ 3 ≈ 69.3V. If it is three-phase four wire and the PT secondary phase voltage is 69.3V, then the input should be 69.3V.

VT Ratio: Set the Phase VT Ratio and Aux VT Ratio (if using auxiliary voltage) on the Sensing Transformers page. VT Connection can be selected as 3W (three-phase three wire), 4W (three-phase four wire), or single-phase (AN/BN/CN/AB/BC/CA). The 27/59 Pickup Mode allows for the selection of PN (phase neutral) or PP (phase phase), which affects the calculation benchmark for overvoltage/undervoltage protection.

Example of core protection function setting

BE1-700 provides rich voltage/frequency protection, with each function having independent enable/disable, setting, delay, and logical connections. The following illustrates the tuning approach using commonly used functions as examples.

5.1 Overvoltage protection (59P)

Used to prevent system overvoltage from damaging equipment. One of Three (action upon overvoltage of any phase), Two of Three, or Three of Three modes can be set. The setting value is in volts (PN or PP, depending on 27/59 Mode). For example, assuming Pickup=120V (approximately 173% for the 69.3V benchmark), with a delay of 500ms and a fixed time limit. Connect the Trip output of this component to the physical output OUT1 in BEST logic Plus to drive the trip.

5.2 Under voltage protection (27P)

Similar to overvoltage, but operates when the voltage drops. Voltage Inhibit value can be set to avoid brief voltage drops during startup (such as motor startup). For example, suppose Pickup=60V (approximately 86.6%), with a delay of 2 seconds.

5.3 Negative sequence overvoltage (47)

Negative sequence voltage reflects three-phase imbalance and can be used to detect phase loss or asymmetric faults. The setting value is expressed as the phase neutral voltage, but in actual testing, the single-phase injection voltage is three times the setting value (because V2=Va/3 for single-phase input). For example, assuming Pickup=10V (corresponding to a single-phase test voltage of 30V), with a delay of 1 second.

5.4 Overexcitation (24) - V/Hz protection

Used for over excitation protection of transformers or generators. V/Hz reference needs to be set (i.e. rated V/Hz=√ 3 × Vnom/Fnom). Reverse time limit (optional index 0.5, 1, 2) or fixed time limit can be selected, and alarm level can be set. For example, if the transformer manufacturer allows 2 hours for 105% V/Hz and 10 minutes for 120% V/Hz, the inverse time curve (M-1) ² can be set, and the time dial can be selected according to the curve. Chapter 35 of the manual provides the complete curve family.

5.5 Frequency Protection (81)

Overfrequency or underfrequency can be set, and the source can be selected from phase voltage or auxiliary voltage. Used for load shedding or islanding detection. The setting accuracy is ± 0.01Hz, and the minimum delay is 0 (instantaneous).

5.6 Simultaneous testing (25)

Compare the amplitude, frequency, and phase angle of the phase voltage with the auxiliary voltage, and output a signal to allow closing. Angle compensation needs to be set (if PT wiring causes inherent phase shift). The voltage difference, slip frequency, and slip angle are all independently set.

5.7 Other auxiliary functions

Virtual switch (43): A logical switch that can be operated on software or a panel, used for switching on/off protection or changing the operating mode.

Logic Timer (62): Provides multiple timing modes (delayed on/off, monostable, oscillation, integration, etc.) for complex logic coordination.

Recloser (79): Automatic reclosing up to 4 times, in conjunction with circuit breaker status and external locking.

Circuit breaker control (101): Simulate the opening and closing buttons of the circuit breaker, which can be operated locally/remotely.

Programmable Logic Plus Settings

The strength of BE1-700 lies in its fully programmable logic. BEST logicPlus uses a graphical drag and drop method to connect protective components, inputs, outputs, timers, gate circuits, and more. The default logic is overvoltage/undervoltage trip (Trip of 59P-1 and 27P-1 is connected to OUT1 through OR gate). To lead the Pickup signal of 59P-1 to OUT2 as an alarm, simply connect the Pickup output of 59P-1 to the input of OUT2. Each output can have custom labels (such as' overvoltage alarm '), which will appear in the fault report and SOE.

After modifying the logic, it must be 'Save' and 'Upload Logic to Device' to take effect. Note that logical changes will not be automatically saved to the file, and the. bst4 settings file needs to be manually saved.

On site testing and verification (emphasis)

During acceptance or regular calibration, it is necessary to verify the measurement accuracy, action value, and delay of the relay. Chapters 37-47 of the manual provide detailed testing steps covering various functions. The following summarizes general principles and key testing methods.

7.1 Test Preparation

Use BESTCOMSPlus to read and save the current settings to prevent changes during testing.

Clear all targets and alarms (press Reset on the Targets and Alarms screens).

For each test, temporary configuration logic is used to output the corresponding Trip and Pickup to idle output contacts (such as OUT2 for Pickup and OUT1 for Trip) for easy monitoring with a multimeter or timer.

7.2 Verification of Voltage Measurement Accuracy (Acceptance Test)

Apply voltage to phases A, B, and C using a three-phase voltage source (e.g. 100V), and check the secondary voltage reading in the Meter. The error should be within ± 0.5%. Simultaneously check whether the calculated values of V1, V2, and 3V0 conform to theory.

Add fundamental wave and third harmonic separately to the auxiliary Vx input to verify accuracy.

7.3 Over/Under Voltage and Negative Sequence Action Value Test

Overvoltage: Set Pickup=125V with minimum delay (50ms). Slowly increase the voltage until LED/Out2 is closed, record the action value, which should be within 125V ± 2%; Reduce the pressure again and record the return value (which should be 98% ± 1% of the action value).

Undervoltage: Similar, but acting to reduce voltage, the return value should be 102% ± 1% of the action value.

Negative sequence (47): Apply a single-phase power supply between A-N, and since V2=Va/3, if Pickup=42V, the test voltage should act at approximately 126V. Record action values and return values (98% ± 1%).

7.4 Delay Verification

Set Time Delay=2s, apply a step (if overvoltage occurs, jump from normal to 1.2 × Pickup); If the voltage is insufficient, it will jump to 0.8 × Pickup; The frequency jumps to 0.5Hz. Using a timer, the time from applying the signal to closing OUT1 should be within the range of 2s ± 0.5% or ± 2 cycles (whichever is greater). If the delay is extremely small (such as 50ms), the output relay action time needs to be considered.

7.5 inverse time V/Hz (24) test

Set Pickup=2.1 V/Hz (105%), Curve Index=2, Time dial=0.5. Apply the rated frequency of 60Hz and raise the voltage to 132V (110% V/Hz, as 132/60=2.2, 2.2/2.1=1.048, but the actual calculation needs to be based on the formula. Table 40-5 in the manual shows that 110% corresponds to 50s). Measure with a timer, with a deviation of ± 5%.

7.6 Simultaneous testing (25) testing

If both the phase voltage and auxiliary voltage are set to 120V, 60Hz, and in phase, the Sync output should be closed.

Change the amplitude of one side and record the action boundary (which should meet the Voltage Difference setting).

Change the phase angle and record the action boundary (Slip Angle setting).

Change the frequency and record the sliding frequency action boundary.

7.7 Contact input/output and communication verification

Stimulate IN1 with external wet voltage, observe the changes in Meter → Status → Input status, and check the SOE records.

Use the Output Override function to force OUT1 to close, and use a multimeter to confirm the continuity of the contacts.

Test USB and Ethernet (if optional) communication, as well as IRIG-B synchronization.

Fault report and event record analysis

BE1-700 has built-in fault recording (COMTRADE format) and SOE (sequence event recording). The fault trigger is defined by the Fault Trigger logic block (Pickup and Logic inputs). Whenever the protection component Pickup or external trigger signal is valid, pre fault and post fault data are recorded. The fault report includes voltage phasor, frequency, target, fault clearing time, etc. Fault record files can be downloaded through BESTCOMSPlus and analyzed using BESTdata software. SOE records all numerical changes with a time resolution of 1ms and can store up to 255 entries in a loop.

Security and Password Management

Multi level password protection (Read, Control, Operator, Settings, Design, Admin). The default administrator username/password is' A '. User and port access levels can be customized in Device Security Setup. Note: If the Secure Access Level of a certain port is set to None, the port will be disabled. If all ports are set to None, the relay cannot operate and needs to be returned to the factory.

Maintenance and firmware upgrade

BE1-700 is a solid-state digital device that only requires regular inspection of wiring and cleaning on a daily basis. If stored for a long time, power on for 30 minutes every year to maintain the performance of the electrolytic capacitor. The firmware upgrade can be performed through the Upload Device Files function of BESTCOMSPlus. After the upgrade, the settings file needs to be restored (the upgrade will clear the report and restore the default values).