ABB UNITOL 1010/1020 AVR Compact IGBT Automatic Voltage Regulator

Measure the resistance between the excitation output terminals to determine if the rotor circuit is open.

Fault 2: Voltage instability or oscillation

Possible reasons:

Improper PID parameter setting (high gain).

Voltage measurement signal interference (poor PT wiring, common mode interference).

The speed regulation of the generator's prime mover is unstable (frequency fluctuations cause voltage fluctuations).

Excitation power source fluctuation (abnormal PMG output).

Troubleshooting steps:

Observe the waveforms of terminal voltage, excitation current, frequency, etc. through CMT1000 to determine the oscillation frequency.

Temporarily reduce the proportional gain (KP) of AVR and observe whether the oscillation weakens. If it weakens, the PID needs to be readjusted.

Check if the PT secondary circuit wiring is secure and if the shielding layer is single ended grounded. You can try changing the voltage measurement mode from three-phase to single-phase to see if it improves.

Check the prime mover speed regulator to ensure that the frequency stability is within the allowable range.

Fault 3: Uneven distribution of reactive power after grid connection

Possible reasons:

Droop compensation settings are inconsistent.

CT polarity or ratio error.

VDC mode (island sharing) is not configured correctly.

Troubleshooting steps:

Check if the voltage sag coefficient of each parallel unit is the same. Usually set at 4%.

Verify CT wiring: Ensure that the CT polarity of all units is consistent, and that the current input phase of AVR corresponds to the voltage.

For multi unit operation on isolated islands, enable VDC mode and configure RS485 communication. Check whether the reactive power readings of each unit are consistent through CMT1000.

Fault 4: The dual channel system cannot automatically switch

Possible reasons:

The CAN communication cable is disconnected or has poor contact.

The set value tracking of the backup channel is not enabled.

Backup channel self diagnosis failure (such as internal fault).

Troubleshooting steps:

Check the CAN bus connection between two UNITOL 1020 cables (cable length<3m).

Check the dual channel configuration in CMT1000 and confirm that the setpoint tracking and switching logic is enabled.

Check the status words of the backup channel for any fault codes.

Manually simulate a main channel fault (such as disconnecting the main channel power) and observe whether the backup channel takes over within a few milliseconds. If not, check the interlock logic of the output contactor.

Fault 5: PSS not working or poor damping effect

Possible reasons:

PSS has not been deployed (usually requiring external contacts or software enablement).

The active power of the generator is lower than the PSS start-up threshold.

PSS parameters are not tuned or do not match the impedance of the power grid.

Abnormal speed/power input signal.

Troubleshooting steps:

Confirm that the PSS function package has been installed and enabled in CMT1000.

Check the PSS startup threshold (usually 10-30% rated active power) and confirm that the current power is above the threshold.

Contact ABB for PSS parameter tuning services (based on on-site measurements or simulation models).

Utilize the "white noise" injection function of PSS (if available) to analyze the system frequency response and optimize parameters.

Lifecycle Management and Technical Support

ABB provides a comprehensive full lifecycle service model for the UNITOL 1000 series, helping customers extend equipment life at the lowest cost.

Life cycle stages:

Active and Classic Stage: Provide complete spare parts, preventive maintenance, fault repair, upgrade and renovation services.

Limited stage: It is recommended to start planning upgrades or renovations to the latest technology.

Available lifecycle services:

Technical optimization support (such as PSS parameter tuning).

Spare parts supply (key spare parts: IGBT module, control board, power board, fan).

Preventive maintenance (regular cleaning, terminal tightening, inspection of cooling fans, capacitor aging testing).

Upgrades and modernization (such as upgrading from LIGHT to FULL, or upgrading from single channel to dual channel).

Technical support channels:

Global 24/7 Hotline:+41 (0) 844 845 845

Dedicated email: unitrol1000support@ch.abb.com

ABB University provides standard and customized training (online and on-site).

Interactive e-Learning program that enables self-learning of product knowledge and operations.

Suggestions for spare parts management:

For critical units, it is recommended to reserve at least the following spare parts:

UNITROL 1020 body (or spare control board)

PM40 module (if used)

cooling fan

Fast melting (for power circuits)

Grid Code Compliance Support

With the increasing proportion of new energy grid connected, grid operators have increasingly strict requirements for generator sets. The UNITOL 1000 series supports grid compliance through the following features:

Built in PSS: damping oscillation to improve dynamic stability.

Fast voltage drop detection: AVR response time<20 ms (three-phase measurement), ensuring fast strong excitation during fault crossing.

Detailed simulation model: ABB provides computer representations of control algorithms and IEEE standard models for system simulation research.