P74x/EN IT/N
  (IT) 1-
 
1.  DOCUMENTATION STRUCTURE 
The manual provides a functional and technical description of the MiCOM protection relay 
and a comprehensive set of instructions for the relay’s use and application. 
The section contents are summarized below: 
P74x/EN IT    Introduction 
A guide to the MiCOM  range of relays and the documentation structure. General safety 
aspects of handling Electronic Equipment is discussed with particular reference to relay 
safety symbols. Also a general functional overview of the relay and brief application 
summary is given. 
P74x/EN TD    Technical Data 
Technical data including setting ranges, accuracy limits, recommended operating conditions, 
ratings and performance data. Compliance with norms and international standards is quoted 
where appropriate. 
P74x /EN GS   Getting Started 
A guide to the different user interfaces of the protection relay describing how to start using it. 
This section provides detailed information regarding the communication interfaces of the 
relay, including a detailed description of how to access the settings database stored within 
the relay. 
P74x /EN ST    Settings 
List of all relay settings, including ranges, step sizes and defaults, together with a brief 
explanation of each setting. 
P74x /EN OP   Operation 
A comprehensive and detailed functional description of all protection and non-protection 
functions.  
P74x /EN AP   Application Notes 
This section includes a description of common power system applications of the relay, 
calculation of suitable settings, some typical worked examples, and how to apply the settings 
to the relay. 
P74x /EN PL    Programmable Logic 
Overview of the programmable scheme logic and a description of each logical node. This 
section includes the factory default (PSL) and an explanation of typical applications.  
P74x /EN MR  Measurements and Recording 
Detailed description of the relays recording and measurements functions including the 
configuration of the event and disturbance recorder and measurement functions. 
P74x /EN FD    Firmware Design 
Overview of the operation of the relay’s hardware and software. This section includes 
information on the self-checking features and diagnostics of the relay. 
P74x /EN CM   Commissioning 
Instructions on how to commission the relay, comprising checks on the calibration and 
functionality of the relay.  
P74x /EN MT   Maintenance 
A general maintenance policy for the relay is outlined. 
P74x /EN TS    Troubleshooting 
Advice on how to recognize failure modes and the recommended course of action. Includes 
guidance on who in General Electric to contact for advice.