Power system protection

Types of MCB

Selection of Transformers:  Transformer size/s must be selected according to the maximum expected load and possibility of future expensions.  The size of transformer may be selected from power ratings given below to supply present and future loads. Commonly Available Ratings for Substation Transformers Powers: 25 kVA, 50 kVA, 100 kVA, 250 kVA, 400 kVA, 630 kVA, 800 kVA, 1000 kVA, 1250 kVA, 1600 kVA, 2000 kVA Primary Voltages (line-to-line): 6 kV, 7.2 kV, 10 kV, 12 kV, 22 kV, 24 kV, 31.5 kV, 33 kV, 34.5 kV, 35 kV, 36 kV Secondary Voltages (line-to-line): 380 V, 400 V.

Substation design Selection of substation equipment: Selection of transformers. Ratings of Circuit Breakers . Ratings of Switch Disconnecters (Load-break switches). Ratings of Isolators (Disconnecters) Characteristics of Voltage Transformer. Characteristics of Current Transformers.

IEC 60255 defines the standard IDMT curves and  their equations for calculating relay action time, to achieve optimal coordination  and selectivity  a protection engineer could shoose any of the curves based on the equipment damage curve, fuse blowing curve, or to coordinate other DMT/IDMT elements. https://www.facebook.com/share/p/YyVdcnxP5pX1UDCk/?mibextid=oFDknk

This page brings together engineers from different countries of the world, in the field of electricity and electrical protection for various systems.  You will find files and discussions that every engineer and technician in this field needs. https://www.facebook.com/profile.php?id=100072324437820