ABB UNITOL 1010/1020 AVR Compact IGBT Automatic Voltage Regulator

Real time clock: provides an accurate time reference for event and data recording, and supports time synchronization through Ethernet (SNTP).

4. Power System Stabilizer (PSS)

As a supplementary option to the FULL version, PSS complies with IEEE 421.5-2005 standard 2A/2B type. Its function is to add excitation control signals, dampen low-frequency power oscillations between the generator and the power grid, and improve dynamic stability. For grid connected power generation projects that require Fault Ride Through, PSS is often a mandatory function.

Software selection suggestions:

Single machine island operation without remote communication requirements: LIGHT is sufficient.

Simple requirement for communication or grid connection with the upper system: BASIC.

Require automatic synchronization and detailed fault recording: FULL.

Need to pass grid compliance testing (such as BDEW, ERCOT, etc.): FULL+PSS.

Debugging and Maintenance: CMT1000 Tool Practice

The standard tool for the UNITOL 1000 series is the PC based CMT1000 debugging and maintenance software, which comes with the device on the CD. This software connects to AVR via Ethernet or USB, providing an intuitive graphical interface.

The main functions of CMT1000 are:

Online parameter settings: All regulator parameters, limiter settings, I/O configurations, communication parameters, etc. can be modified online. Support parameter upload and download.

Real time monitoring: Display real-time data such as terminal voltage, excitation current, power, frequency, etc. in the form of instruments, trend charts, numerical tables, etc.

Event and Data Recorder Reading: Download the event list and fault waveform data stored internally in the device for fault analysis.

Dual channel configuration: For redundant systems, the parameters and switching logic of the primary/backup channels can be configured.

PSS parameter tuning: assists in calculating and setting PSS gain and time constant, and can be used for simulation testing.

Firmware upgrade: Upgrade AVR firmware via USB or Ethernet to obtain the latest features and fixes.

Debugging practical process (taking a newly installed diesel generator set as an example):

Pre check: Confirm that the generator, exciter, CT/PT wiring is correct, and the AVR power input and auxiliary power supply wiring are correct.

USB power configuration: Before starting the generator, connect the laptop and AVR with a USB cable and turn on CMT1000. At this time, the AVR controller is powered on (but the power part is not working), and parameter presets can be performed.

Import parameter file: Based on the generator excitation data table, pre input voltage setpoint, PID initial value, limiter setpoint, etc. Save parameters to device flash memory.

First start-up (pressure building): Start the prime mover and reach the rated speed. AVR will automatically establish the terminal voltage (usually 80% -100% rated value). Monitor the pressure building process through CMT1000.

Voltage regulator tuning: Conduct step response testing (such as 5% voltage step), observe overshoot, adjustment time, and oscillation frequency. Adjust the PID parameters until they meet the requirements.

Limiter verification: Simulate over excitation, under excitation, overcurrent and other working conditions to verify the limiter action value and action time.

Dual channel switching test (if applicable): manually turn off the main channel power and verify that the backup channel has no interference connection.

PSS input (if applicable): After grid connection, input PSS and use white noise or on-site testing instruments to verify the damping effect.

Data logger settings: Configure triggering conditions (such as voltage drop exceeding 10%) to ensure automatic waveform recording in case of future faults.

Common troubleshooting and practical cases

Based on on-site experience, the following are several common types of faults and their troubleshooting methods for UNITOL 1010/1020.

Fault 1: Generator unable to build voltage (no voltage output)

Possible reasons:

No remanence or low remanence voltage.

The auxiliary power supply is not powered on (AVR controller is not working).

Excitation power input missing (PMG output fault, loose wiring).

Open circuit of excitation circuit (poor contact of rotor slip ring carbon brush, broken excitation winding).

Troubleshooting steps:

Check the power indicator light on the AVR panel. If it does not light up, measure whether the input voltage of the auxiliary power supply meets the range of 18-420V DC or AC.

Connect the CMT1000 to the AVR and check for any alarm messages (such as "Field Overcurrent", "Loss of Sensing", etc.).

Check if the excitation power input (three-phase AC) is normal. For PMG excitation, check the output voltage of the PMG stator.

Try the "Field Flashing" function: Many AVRs support external excitation voltage building signals. If the AVR has this input, an external DC power source (such as a battery) can be applied to the excitation output for a short period of time to observe whether the voltage is established. Once pressure is established, the self-excited circuit can usually be maintained.