What protection relays are used with power transmission circuits？

In the beginning, we have to know that all circuits and transformers that work in High Voltage, such as (220KV - 380KV - 500KV-132KV) have Main1, Main2, and we mean two protection devices Tow Protection Relays on them the same Protection Function and the same Setting, but each device has a separate source of nutrition from the other and the purpose is the reliability of the system where any problem occurs on the main1, whether in the feed path or Failure on the Relay, the Main2 is in service and protects the circuit Or the Adapter from any faults.

We note that the Protection Relays used from different manufacturers such as MiCOM, ABB  - Protections are divided into two parts:  

- Instantaneous protections, which means that the operating time has (zero sec) such as:

- 1- Differential protection of 87L lines  

2- Distance protection in Zone 1  

3- Directional ground leakage protection with 67N High Stage  

- Delay Time protections  

1- Protection distances in Zone 2-3-4  

2- Directional ground leakage protection at 67N Low Stage  

3- Connection protection on SOTF malfunction  

- As for automatic reconnection, we find that it works with protections that disconnect instantaneously, while Block with protections that work with time in Delay Time and Switch Onto Fault protection

- In some schemes, we find that non-directional current surge protection is also used with power transmission circuits, and the working philosophy for it is that it works as a backup for the main protections, meaning if a block occurs on the Line Differential and a block also occurs on the Distance Protection, we find that there is an activation to protect the increase of the non-directional current, and this mode is called in some Relays as the Emergency Mode, as in 7SD SIEMENS Relay