In power systems, it is essential to limit short circuit currents to avoid extensive damage to equipment and maintain system reliability. This article outlines several solutions to accomplish this goal.
Firstly, in existing systems, the use of column separation in higher voltage levels can help limit short circuit currents. Additionally, employing backup power sources can supplement the reduced reliability caused by separating columns. While in the construction stage, installing series reactors can help limit short circuit currents that are too large.
Increasing the transforming ratio of protection level TA is another effective method, which requires determining the maximum short-circuit current that may occur at the location of relay protection devices and the transformer's loading capacity and saturation ratio. However, increasing the transforming ratio of TA adversely affects monitoring the relay protection devices' secondary circuit.
To reduce the secondary load on current transformers, this article recommends installing relay protection devices locally and utilizing protection principles that are less sensitive to current saturation. It also suggests lowering the secondary rated current of the TA.
Overall, this article provides various methods for limiting short circuit currents and reducing the secondary load on current transformers. These practices are critical to enhancing system reliability and safety.