Renewable energy sources such as solar and wind power often have unstable and intermittent power supply that affects the power grid frequency and voltage. Setting up an ESS (energy storage system) can help smoothen the energy input and increase the grid capacity. Moreover, the fast charging and discharging of the ESS enable it to follow the load fluctuations of the power system. An ESS can actively adjust its charge/discharge function to protect the power system's quality, safety, and frequency.

The popularization of EVs and the growing demand for grid-connected ESS devices are stimulating the commercialization of decentralized microgrids for energy storage as well as the development of power converters toward bidirectional designs. High efficiency, high voltage conversion, and high power density trends are spurring the gradual increase in demand for bidirectional power supply test equipment.

Chroma 61800 series of Regenerative Grid Simulators with an output range of up to 500VLN can produce various voltage and frequency forms and use five outputs in parallel to test PCS grid-connected functions up to 525kVA rated power. In addition, the AC load mode can simulate the capacitive and inductive load characteristics of constant current, constant power, constant power group, and current phase lead and phase lag, in order to test the PCS's off-grid functionality. Chroma's newly launched 62000D series of Bidirectional DC Power Supply models incorporate both power supply and load characteristics. The voltage range reaches 1800V and dual-quadrant operation allows energy feedback from the device under test (DUT). The power supply is fit for testing new energy storage inverters; by simulating the charging and discharging conversion of energy storages it eliminates the inconvenience and danger associated with using real batteries.

Chroma has combined our vast experience in the PV industry with the relevant international regulations on ESS, such as GB/T 34120, GB/T 34133, IEC 62933, and SGSF-04, as well as the German VDE-AR-N 4105 standard on generators connected to the low-voltage distribution network. The result is our updated comprehensive overview and discussion in Chroma's Power Conversion System for ESS Test Guide (incl. PV inverter function).

The newly added over-frequency effective power feeding control test serves to meet the recent international promotion of ESS automated frequency control service testing. For the short-circuit current test requirements of the VDE standard, the test guide also proposes a technology to accurately measure the maximum output short-circuit current of the DUT. This will resolve any disputes over whether the protection mechanism of the DUT or of the grid simulator is the first to activate as well as eliminate the risk of power trips caused by a short circuit connected to the power grid. With Chroma 8000 ATS as the base, the platform can combine complete series of power grid/battery simulators and test equipment to complete nearly 30 automated test items detailed in the test guide.

The new version of the Power Conversion System for ESS Test Guide ((incl. PV inverter function) is now available for free download. Please leave your contact information for additional technical consultation on inverters. We are happy to be of service!