Basler BE1-40Q demagnetization relay

Basler BE1-40Q demagnetization relay

Chapter 1 Overview General Information

1. Core role of the product

Synchronous generator demagnetization backup protection, monitoring reactive power flow at the machine end: When the excitation is insufficient/completely demagnetized, the generator absorbs a large amount of inductive reactive power from the system (leading phase operation), causing overheating of the rotor damping winding, out of step oscillation, and damage to the unit; This machine detects reverse reactive power and delays tripping to compensate for the risk of low excitation limiter failure in the excitation system.

Two types of fault conditions: demagnetization

Insufficient reactive power in the system: After the generator loses excitation, the rotor slides and loses synchronization;

The system can supply reactive power: the generator is equivalent to an induction generator, and the damping winding continues to heat up, leading to a sharp decline in lifespan.

2 Protection action characteristics

Action boundary: A straight line inclined at an angle of 8 ° with the horizontal axis on the P-Q complex plane, located inside the static stability limit of the generator; The setting is completed through the reactive power (VAR) threshold;

Criterion principle: Collect terminal line voltage and phase current, calculate absorbed negative reactive power (incoming reactive power), and start delay when exceeding the set value;

Delay characteristics: timed limit of 0.1~9.9s, step size of 0.1s; the delay dial is set to instantaneous action at 00, used to avoid external faults, power swing transient processes, and prevent misoperation.

3 Model Style Encoding Rules

Model BE1-40Q+segmented style code, defining sampling, output, power supply, indicator, and installation method;

Example F3E-E1O-B1S2F disassembly:

F: 60Hz single-phase current acquisition; 3: 120V voltage sampling, with a range of 25~1000var;

E: Single channel normally open main output; E1: Time limited characteristic; O: 48VDC power supply;

B: Current driven fault indicator; 1: Manual testing button on the panel;

S: Power status contacts; 2: 1 normally closed auxiliary output; F: Semi embedded S1 shell.

4 Core Electrical Technical Parameters

(1) Sampling circuit

Current: Suitable for standard 5A CT, internal CT continuous 10A, 1min 15A, 1s200A, sampling impedance<0.1 Ω;

Voltage: Three line voltages of 120/208/240V PT input, with each phase load<1VA;

The frequency is suitable for 45~65Hz.

(2) Reactive power setting range (divided into HI/LO two gears+10 gears TAP dial)

Divided into four ranges based on PT voltage, with a minimum of 5var and a maximum of 2000var; Setting accuracy: ± 2% of the set value or ± 0.1var (whichever is greater); Return value ≥ 95% of action value.

(3) Delay parameter

The timing limit is 0.1~9.9s, with an accuracy of ± 5% or 50ms; when the reactive power is lower than the set value, the timer will immediately reset to zero.

(4) Output contact capacity

120VAC: continuous 7A on/off;

250/500VDC: short-term 0.2s load capacity of 30/15A, long-term 7A, breaking only 0.3A; inductive load uniformly breaking 0.3A (L/R=0.04).

(5) Control power supply with multiple specifications

Model Rated voltage Operating range Power consumption Special

R 24VDC 12~32V 1.9W requires 14V for startup

O/S 48/125VDC 24~150V 1.9/2.2W DC universal

P 120VAC 90~132V 18.4VA AC

T 250VDC/240VAC 68~280V/90~270V 2.3W/32.1VA high voltage cabinet

The power supply has no polarity and is designed with low power consumption isolation.

(6) Fault indicator (choose one from two)

Built in electronic driver: no current requirement, compatible with normally closed output;

Current driven: The tripping circuit must be ≥ 200mA to light up, with a short-term of 30A/0.2s and a long-term of 7A;

Before 2007, mechanical disk locking was used, but now unified electronic LED locking is used. When the power is turned off and restored, the fault memory needs to be manually reset.

(7) Environment, Reliability, and Certification

Temperature range: operation -40~70 ℃, storage -65~100 ℃; Weight 6.12kg, standard S1 shell;

Experiment: Three axis 15G impact, 2G 10-500Hz vibration; Voltage resistant whole machine to ground 2121VDC, input and output 1500VAC; Meet IEEE C37.90 surge and RF anti-interference requirements;

UL508 certification, no UL approval for contacts>250V.

Chapter 2 Panel Control and Indicator Lights

All components are pre installed, with a total of 9 sets of components:

TAP setting knob A: 10 gears, matched with high and low range setting reactive power action threshold;

Action indicator light B: The red LED stays on when the reactive power exceeds the limit;

Power LED C: The device is powered on normally and lights up;

Fault reset switch D: Clear the latch fault indicator light;

Range comparison table E: Reactive power values corresponding to each gear printed on the panel;

Output test button F: Pressing the insulation rod, manually driving the trip/auxiliary contact;

Lock fault light G: remains lit after demagnetization action, manually reset;

Delay dual dial wheel H: 10 seconds, 10 seconds, 00 is instantaneous;

HI/LO range switch I: Switch between high and low ranges for reactive power measurement, and can be switched when live.

Chapter 3 Functional Description

1. Overall signal process

Terminal AB line voltage+B-phase current → Built in PT/CT isolation scaling → Voltage phase shift 68 ° lag → Multiplier calculation of instantaneous reactive power → Integral output of average reactive power DC → Comparison with setting reference → Over limit start time limit → Drive main output, auxiliary contacts, and fault lights.

This machine is sensitive to phase sequence, and the manual defaults to ABC phase sequence wiring.

Detailed explanation of 2 core modules

Voltage phase shifting unit

Unified collection of voltage hysteresis offset of 68 °, so that when the power factor angle θ=-90 °, the action boundary forms an angle of 8 ° with the horizontal axis, matching the generator static stability curve, and matching the official setting calculation formula.

High and low range CT secondary switching

Internal CT dual side winding, measuring high reactive power in HI mode and low reactive power in LO mode, improving the accuracy of setting small phase conditions, and ensuring risk-free live switching.

Multiplication+Integral Converter

Multiply the instantaneous values of voltage and current, filter out AC pulsation, and output a DC level proportional to the average absorbed reactive power; The integration speed varies with the fault multiplier.

Comparison and timed loop

When the reactive DC exceeds the setting reference, light up the Pickup light and start the timer; The reactive power drop will immediately reset the timer.

Classification of output circuits

Main trip output: NO/NC optional, used to trip the main switch of the development motor;

Auxiliary output: NO/NC/SPDT three options, used for alarm and signal upload, with no power status contacts after selection;

Power status contact: The normally closed contact is disconnected during normal power supply; Close in case of power loss/internal ± 12V power failure, abnormal power supply to the monitoring device.

3 Key Design Details

When unplugging the terminal plug, the CT input automatically short circuits to prevent CT open circuit and high voltage from injuring people.

Chapter 4 Installation

1. Receipt, Storage, and Maintenance

Check the model and appearance of the goods upon arrival, and report any damages during transportation to the carrier immediately;

Backup equipment should be stored in moisture-proof original boxes and powered on for 30 minutes every year to extend the lifespan of electrolytic capacitors;

No regular preventive maintenance is required, only periodic functional verification is needed, and any malfunctions should be reported to the manufacturer's after-sales service.

2. Mandatory requirements for installation safety

The tripping circuit of the current driven indicator must be ≥ 200mA;

Before the insulation withstand voltage test, unplug the terminal and the relay, otherwise the demagnetization protection will be lost;

Confirm the stability of the operating conditions of the unit before disassembly to avoid major accidents caused by demagnetization and lack of protection;

Grounding: The cabinet grounding terminal uses ≥ 12AWG copper wire for independent grounding, and multiple devices are separately grounded;

EMI specification: Parallel reverse freewheeling diode when driving external coils with contacts (Rev S added);

Solid state without mechanical components, no mandatory vertical installation requirements, and can be fixed at any angle.

3 Shell and wiring

Two installation schemes for S1 shell: semi embedded and protruding; Provide single end/double end backplate, side view, and panel opening dimensions (inches+millimeters);

Wire specification: Conventional wiring ≥ 14AWG;

The drawing includes: voltage and current sampling wiring, main trip/auxiliary output circuit, built-in CT/PT terminals, internal wiring diagram for current/built-in indicator matching, all based on ABC phase sequence.

Chapter 5 Setting and Testing

On site setting calculation (core process)

Based on the P-Q capacity curve of the manufacturer's generator, the negative reactive power setting value is determined by the intersection point of the static stability limit, and the panel TAP gear is converted in four steps:

Determine the absorption reactive power per unit based on the static stability limit (e.g. -0.4pu);

Convert three-phase primary reactive power to single-phase primary reactive power;

Convert the reactive power on the secondary side of the relay through CT and PT ratio conversion;

Match the HI/LO range and TAP gear of the panel.

Attached is a complete example of setting calculation for a 100MVA generator.

2. Three types of standard testing for the whole machine

(1) Action value verification

Apply rated voltage, with a current lag of 60 °; Slowly increase the current until the Pickup light is on;

Record voltage and current, calculate reactive power and compare it with panel gear, with an error of ± 2%;

Repeat the full range and high-low range measurements in sequence.

(2) Delay accuracy verification

Apply twice the action current and verify three delay levels of 1.0s, 5.5s, and 9.9s respectively, allowing for a ± 5% error.

(3) Protection characteristic curve mapping

Change the current phase angle (-20 °~-120 °), record the operating current at each angle, calculate the corresponding P and Q values, draw the P-Q operating boundary curve, verify that the 8 ° tilt characteristic is consistent with the design, and provide a blank drawing template.

3 Test Circuit Standard Wiring

Standard test wiring diagram for voltage source, current source, phase adjustment, timing device, and power meter, specifying the reference values for test current corresponding to different PT voltages.