This paper will present a brief overview of some advantages and disadvantages of both current only schemes and distance/directional schemes, as well as some of the problems that may arise as the source to line impedance ratio increases.
This paper describes the dynamic characteristic of phase mho relays which use the faulted phase voltage as the polarizing quantity, and which have 'memory action' in the polarizing circuit.
This paper will discuss the operating principles of ground distance functions and some of the limitations, or problems, that can be encountered in their application.
The purpose of this paper is to discuss fundamental features of the three types of functions and possible problems that may be encountered in their design and application.
Grid Automation 
[354k]