The application of multiterminal (MT), high-voltage dc (HVdc) (MTdc) grid technology requires test procedures for the operation and implementation of the protection solutions. The test procedures are usually derived from experience and from extensive measurement data, which, at present, are still not widely available. Based on a hardware-in-the-loop (HIL) method, advanced dc protection testing strategies, utilizing existing experience for ac grids and requirements for MTdc grids, may overcome this gap.
This article proposes procedures and guidelines for testing system-level dc protection based on the functionality of MTdc grids for both primary and backup dc protection. Specific performance criteria have been defined, based on multicase testing and statistical analysis, with the considerations of related critical testing parameters for each functional requirement of the dc protection. Accordingly, procedures for a dc protection testing environment and various fault scenarios are defined. The proposed algorithm test procedures will contribute to the standardization of dc protection system design and testing.