A New Method for Three-Phase Voltage Detection and Protection
Based on Reference Frame Transformation
Technology description
A distributed power generation system is required to stop the flow of electricity to the grid within a specified time after detection of an abnormal grid voltage. Traditionally three-phase grid voltage protection is achieved by calculating and monitoring the root-mean square (rms) values of grid voltages from the instantaneous voltage data. This requires continuously accumulating the sampled voltage data over one or more cycles before an rms value is calculated, which not only demands lengthy computations but also causes a time delay in response to a voltage fault.
This technology is a new method for three-phase grid voltage detection and protection based on reference frame transformation. It has been implemented on a 30kW three-phase grid-connected inverter. By calculating and monitoring the instantaneous magnitude of the grid voltage vector in the synchronous d-q reference frame, this method has an immediate response for grid voltage faults. The simulation and laboratory tests on the inverter have verified that the new method is simple and accurate, and offers a fast dynamic performance. Reliable, fast and accurate voltage detection is critical to safety and protection of distributed power generators (DG) as well as power systems.
The potential users will be the inverter manufacturers for distributed power generators, such as, but not limited to, micro turbines, wind turbines, small hydros and photovoltaic systems. It is also applicable for protection and control equipment manufacturers for power systems. The method will allow faster and more accurate detection of the magnitude of three-phase voltages.
Advantages
The new method for three-phase voltage detection and protection has several advantages over the traditional model:
- Reduces lengthy computations
- Provides an immediate response for grid voltage faults
Stage of development
A prototype is developed and beta tests have been successful on a small scale.
Intellectual property
Canadian Patent Pending
This technology is available for licensing.
Contact information
Office of Research Services, Industry-Government Services
University of New Brunswick
Phone: (506) 453-4674
partner@unb.ca
