Some notes on the High Voltage Ride Through (HVRT) test of the inverter

　　Q:

　　What is the high voltage ride through test of the inverter?

　　A:

　　A test item to verify whether the inverter can work normally when the grid voltage swells fault.

　　When the inverter is deployed in a photovoltaic power station, the rated voltage of the grid terminal needs to be determined according to the actual situation of the local power station, usually 400V, 600V, 800V and other line voltage levels, and the converted phase voltage is 230V, 346V, 461V, etc.

　　As a key equipment in a power station, the inverter needs to be able to cope with various abnormal conditions of the power grid. High voltage ride through is a test item that simulates the voltage swell of the power grid. The above figure is a typical high voltage ride through requirement voltage curve envelope diagram, when the duration is not longer than 0.5 seconds, the voltage amplitude is not higher than 130% of the rated value, and the subsequent duration is not longer than 9.5 seconds, and the voltage amplitude is not higher than 120% In the case of rated value, the inverter should not run off-grid and have the ability to continuously adjust active power and the ability to inject reactive current into the power system during this period.

　　Different countries and regions and different manufacturers have different high voltage ride through requirements for specific inverters, but basically the test equipment is required to provide a controllable output up to 130%-140% of the inverter rated voltage. If It is a 600V line voltage (346V phase voltage) inverter, and the grid simulator needs to output up to 840V line voltage (485V phase voltage); if it is an 800V line voltage (461V phase voltage) inverter, the grid simulator needs to output up to 1120V line voltage (647V phase voltage).

　　Q:

　　How to realize the high voltage ride through test of the inverter?

　　A:

　　Use the power grid simulator ultra-high voltage range to simulate the voltage swell process to verify the inverter's working condition.

　　For this type of test requirements, the power grid simulator needs to provide a higher output voltage range. For example, in addition to the original phase voltage selection, the MX/RS series power supply of AMETEK California Instruments also provides special ultra-high voltage options, which can expand the output voltage to 500Vrms, 600Vrms or even 650Vrms, and 700Vrms phase voltage, which fully covers the high voltage of different customers. Voltage ride through test requirements.

　　This kind of test instrument generally uses ultra-high voltage components and accurately debugs the output characteristics to ensure the maximum range of output impedance matching, so as to avoid the occurrence of vibration to the greatest extent. At the same time, the heat dissipation channel and the over-temperature protection circuit inside the power supply have also been redesigned to provide such a high-voltage and full-power output within the same machine size.

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