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OneStep Power’s Generator Voltage Response Tester (GVRT) allows for all excitation based testing, without the need to change protection system settings, in a controlled, repeatable manner.

  • High speed networked generator control.

  • Generates real time fault characteristics without risking equipment.

  • Specific fault behaviours, proven through modelling to provide expected results prior to testing.

  • Invisible to ship’s systems, providing a true integrated system test.

How it Operates

How it Operates

Each generator in the power system under test will have a GVRT connected, these are then networked to a master control computer with high-speed time sync. Each GVRT is controlled by an onboard high-speed processor. 

The GVRT is connected between the AVR and the field of the generator. The GVRT will measure readings such as voltage and current and has an internal load which allows the AVR to continue normal operation.

GVRT installation - Normal Condition

During normal operation the GVRT will mirror the AVR output, and in test conditions will vary the excitation voltage. 

GVRT installation - Test Condition

The tests are performed by OneStep’s technicians using pre-programmed test sequences developed by OneStep’s Power Engineers via the control computer, with high speed recording of results to provide actual wave-form responses. 

Technology & Capabilities

OneStep’s GVRT solution uses modern high-speed micro-processors and proprietary  communications to ensure sub-cycle control of the generator exciter voltage.  The GVRT system uses high-speed data capture to record power system responses and display actual real-time waveforms of fault conditions.


This allows OneStep’s Engineers to analyze actual responses and, in conjunction with previously agreed acceptance criteria, a non-negotiable “pass” or “fail” result with no interpretation required. 

The GVRT can be used to test remote power systems with a range of specifications.

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Safety Features

The greatest safety feature of the GVRT is the removal of personnel from the area associated with testing. In traditional power management testing scenarios, personnel are required to interact with live equipment. The GVRT eliminates this, making for a far safer testing solution.

During the GVRT test program all system protections will remain fully operational and no alteration or modification of internal protection and control system settings is required. A significant percentage of IMCA DP incidents associated with power management were reported to have changed system settings during testing and the failure to reset these settings as a cause of the DP event,  the GVRT removes this risk. 

The GVRT is self-monitoring: any internal or external failure which could result in system damage will immediately de-excite the generator. The GVRT is equipped with provisions for generator engine shut-down if specified by client.

Minor failures (for example single board or generator failure) will be identified and selectively eliminated to reduce disruption. 


Additional features include:

  • Armoured and protected cabling between GVRTs and Hub, and suitable securing of cables as they pass along walkways and through doors.

  • A control system which fails to “no-interaction”, allowing the AVR to maintain control of the generator in the event of a GVRT failure.

  • Software signals providing confirmation of timings of tests to ensure all systems are ready to operate and perform test as designed.

  • Double confirmation on the activation of tests

  • Electrical isolation of the GVRT output (no direct path through from supply to field windings)


  • Fast, Repeatable (Historical data), Reliable.

  • Safe testing of system response.

  • Reduced risk - Testing without modifying system's settings.

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