This book provides practical applications of numerical relays for protection and control of various primary equipment namely distribution and transmission networks , HV and EHV transformers and busbars, reactive and active power plants. Unlike other books attempts have been made to address the subject from practical point of view rather than theoretical one which can otherwise be found in most of other text books. The setting, design and testing philosophy of numerical relays as discussed in this book have been successfully applied in the fields on various projects and consequently can be used as a practical guideline for implementation on future projects. The book covers the followings subjects: · Fundamental concepts in the field of power system protection and control; · Required system modelling and fault level analysis for the design and setting of protection and control devices; · Setting and design philosophy of numerical relays of different primary equipment; · Practical application of anti-Islanding schemes for two different systems namely distribution generation (DG) and transmission generation (TG); · Challenges and solutions which are encountered during secondary equipment refurbishment/replacement in brown field substations with inclusion of two practical case studies; · Required tests for factory acceptance tests (FAT), site acceptance tests (SAT), and commissioning tests of numerical relays in conventional and digital substations; · Causes, analysis and proposed mitigation techniques of more than 100 worldwide disturbances which have occurred in different type of primary equipment which have resulted to major system black out or plant explosion or even fatality and; · New and future trend of application of numerical relays including application of super IED for protection and control of multi-primary equipment, implementation of digital substation ,remote integrations ,self and remote testing of IED , distribution networks fault location techniques and fault locators using travelling waves, synchro phasors, time domain line protection using travelling waves, adaptive slope characteristics of differential protection, protection and control schemes of micro grids, mitigation technique for prevention of loss of reactive power plants and transformers due to solar storms.