ABB UNITOL 1010/1020 AVR Compact IGBT Automatic Voltage Regulator

2. Measure input

Terminal voltage (1, 2 or 3 phases): up to 500V AC (direct input, no PT required).

Network voltage (1-phase): up to 500V AC, used for synchronization or voltage matching.

Terminal current (1 phase): 1-5A AC, usually taken from the CT secondary side, used for reactive power droop compensation and power factor adjustment.

Frequency range: 10-150 Hz, covering various speeds from low-speed water turbines to high-speed gas turbines.

3. Control input/output

Analog I/O: 3-channel input (impedance>240k Ω), 2-channel output (impedance 100 Ω), ± 10V range. Can be configured as external input, PID superposition control, additional limit signal, etc.

Digital I/O: 4 dedicated inputs, 8 configurable inputs/outputs. The digital output has a maximum current of 150mA and can directly drive small relays. Additionally, provide a 24V/600mA output for external relays.

Reference voltage output: ± 10V reference, can be used for external potentiometers or sensors.

4. Communication interface

Ethernet： 10/100 MBit/s， Used for connecting CMT1000 debugging tools, Modbus TCP (BASIC and above versions), or system integration.

USB: Supports 1.0/1.1/2.0, cable length<3m, can be used for power supply and configuration.

RS485: configurable baud rate, cable length<500m, supports Modbus RTU or VDC communication. VDC mode allows up to 31 units to achieve reactive load sharing during islanding operation.

CAN: Only used for communication between internal devices of UNITOL 1000 series (such as dual channel configuration or connection with PM40 module).

5. Local Human Machine Interface (HMI)

The device panel is equipped with a local HMI that can display key parameters such as AVR status, voltage, current, frequency, etc. in real time, and can perform basic settings. This is very helpful for rapid on-site inspections and fault diagnosis.

Installation precautions:

The UNITROL 1010/1020 can be directly installed on the generator (end of machine installation) due to its wide temperature range (-40 to 70 ℃) and robust mechanical design (meeting IEC 60068-2-6 vibration level, DNV B level, seismic level 2), ensuring reliability in harsh environments.

When wiring, the power terminal and measurement terminal are physically separated from the I/O connector, which improves electromagnetic compatibility (EMC) immunity. It is recommended to use spring crimping terminals (provided with the equipment) to ensure reliable wiring and quick replacement.

For applications that require dual channel redundancy, such as critical ships or power stations, two UNITROL 1020 can be connected via CAN bus to achieve automatic switching between primary and backup channels. In the event of a primary channel failure, it can switch to the backup channel without disturbance.

Control software function package: in-depth analysis from LIGHT to PSS

ABB provides three ready-made software feature packages and an optional PSS (Power System Stabilizer) for the UNITOL 1000 series. Engineers should select appropriate functional packages based on project grid specifications, unit importance, and budget.

1. LIGHT version (standard on 1010 and 1020)

This version covers basic excitation control functions and is suitable for cost sensitive scenarios that do not require advanced features.

Regulator mode (disturbance free switching):

Automatic Voltage Regulator (AVR): maintains a constant terminal voltage.

Excitation Current Regulator (FCR): Manual mode, maintains constant excitation current.

Power factor regulator (PF): maintains a specified power factor.

Reactive Power Regulator (VAR): maintains specified reactive power output.

Limiter: Ensure that the synchronous machine operates within a safe and stable area.

Excitation current limiter (minimum/maximum)

P/Q under excitation limiter

Stator current limiter

V/Hz (volts/hertz) limiter

Terminal voltage limiter

Soft start and voltage matching.

2. BASIC version (added on top of LIGHT)

Modbus TCP: Implement standard communication with the upper computer system through Ethernet, facilitating data acquisition and control.

Rotating diode monitoring: For brushless excitation systems, this function can monitor the health status of the rotating rectifier and predict faults.

Analog input connected to PID summation point: allows external signals (such as reactive power settings from the power plant controller) to be superimposed on the PID regulator to achieve higher-level control.

VDC mode: In islanding operation, up to 31 units can automatically distribute reactive load through RS485.

Dual channel/monitoring: Based on self diagnosis and CAN communication for setting value tracking, enabling dual channel redundant operation.

3. FULL version (only UNITOL 1020, added on the basis of BASIC)

Synchronization: Built in fast and reliable automatic synchronization function, without the need for external synchronization devices. It can automatically detect voltage difference, frequency difference, and phase angle difference, and issue closing instructions.

Event Logger: Stores up to 500 timestamp events in non-volatile memory, recording important operations, alarms, and faults.

Data Logger: Automatically saves data records of 12 signals for waveform analysis before and after faults.