The increase in distributed generation leads to phenomena like intermediate infeed and inversed power flow on a previously unseen scale. Additionally, variable infeed of renewable energy sources necessitates frequent topology changes, which protection schemes need to compensate for. This poses a challenge for distance and overcurrent protection schemes. Therefore, an increased flexibility of protection schemes is necessary, which is enabled by an adaptive protection concept that dynamically adapts parameters depending on infeed and topology status of the grid.
In order to test and guarantee the functionality of an adaptive protection system, a test framework is implemented in a real-time laboratory. The framework consist of a grid model containing the challenging topologies, which is running in real-time on an RTDS real-time simulator. The analog measurement values produced by the RTDS simulator are amplified by four Omicron CMS devices and serve as inputs for four Siprotec 5 Protection Devices. The interaction of the protection devices with the breakers in the real-time simulation is enabled by the digital front panel inputs of the RTDS Simulator.
The topology of the simulated grid is monitored via TCP/IP using a virtual control center implemented in Python. By using a previously developed IEC61850 client, the protection parameters of the Siprotec devices can be dynamically adapted depending on the state of the real-time environment. The protection configurations for different scenarios were pre-calculated and saved in a database. The test framework delivers a successful proof of concept to verify the adaptability of protection settings.