Using a Multi-Threaded Time-Step To Model a Multi-Function Relay in a Real Time Digital Simulator

By default, a real time digital simulator will execute a simulation case and provide the solution for the controls and power system every time-step (typically 50 musec). The length of the time step is decided by the time taken to execute the longest component algorithm. The component in question may be that for a protective relay which takes in new data only every 1 or 2 milliseconds. The idea behind a multithreaded component is that a protection algorithm does not need to be executed every time-step. A component algorithm can be separated into individual blocks of code processed independently of each other to create a multi-threaded component running within the main simulation. Details are given of this process and how it is applied to several relay models.