In a previously published article, an option was presented to calculate the frequency of an electrical signal from a transition through zero. This article provides an example implementation of a frequency filter.
Using modern software tools, such as Matlab / Simulink, can significantly simplify the analysis of various complex systems. Matlab scripts allow you to automatically run Simulink schemes with changing various parameters.
A differential relay is used in the implementation of the basic protections of various equipment: generators, transformers, power lines, etc. The use of a relay with a braking characteristic prevents the non-selective action of the protection.
The power direction relay is used in the implementation of directional protections, which allow for operation only with a certain power direction in a certain network operation mode.
Inverse time delays are used to implement protections, the response time of which depends on the value of the input quantity. The use of inverse time delays can reduce the trip time of close short circuits with high currents, while ensuring selectivity of protection.