Transient stability analysis with current transformer

Transient analysis with current transformerDr. G. Baskar M.E., FIE., Ph.d.The Principal Kingston Engineering CollegeBy:M. Riyas ahamed(511312411011)12/26/2013M.E(PSE) PS 9231/Project Phase 11Project (phase i)PresentationUnder supervision of:112/26/2013Objective:The objective of this present work is to investigate the performance and transient behavior of conventional electromagnetic current during power system switching faults. The project work has been carried out using MATLAB/Simulink simulation tools. 12/26/2013M.E(PSE) - Project Phase 12Introduction:Current Transformer:Current transformers (CT) are important elements of relay protection because they are the main source of information for the measuring organs of the devices of relay protection, and the accuracy of the transformation of primary currents by high voltage and intervening CT determines the reliability of the operation of the entire protection.

Types of current transformers:Electro Magnetic Current Transformer (EMCT)Hall Effect Current Transformer (HFCT)Magneto Optic Current Transformer (MOCT)12/26/2013M.E(PSE) - Project Phase 13Introduction:- (cont.)Transient:The electrical transients are well known and unavoidable disturbing events that causes severe problems to the electric power systems. The origin of transients are switching transients, lightning, and other faults.12/26/2013M.E(PSE) - Project Phase 14

Scope of work:Different types of switching faults are considered for conventional electromagnetic current transformers (EMCT). The switching faults include symmetrical & unsymmetrical switching, effect of current transformer secondary opening, and the effect of load switching. The system is modeled to be a 120KV constant voltage source supplying a distributed load of 100MVA through a transmission line of 300km length.12/26/2013M.E(PSE) - Project Phase 15Simulation:12/26/2013M.E(PSE) - Project Phase 16

Testing:Effect of Symmetrical & Unsymmetrical switching.Effect of CT secondary open. Effect of Load switching. 12/26/2013M.E(PSE) - Project Phase 17Testing: (Effect of Symmetrical & Unsymmetrical switching)12/26/2013M.E(PSE) - Project Phase 18Testing: (Effect of Symmetrical & Unsymmetrical switching)12/26/2013M.E(PSE) - Project Phase 19

Testing: (Effect of Symmetrical & Unsymmetrical switching)12/26/2013M.E(PSE) - Project Phase 110Effect of symmetrical switchingEffect of unsymmetrical switching

Testing: (Effect of CT secondary open)12/26/2013M.E(PSE) - Project Phase 111Effect of CT secondary open

Testing: (Effect of CT secondary open)12/26/2013M.E(PSE) - Project Phase 112Effect of CT secondary open

Testing: (Effect of load switching)12/26/2013M.E(PSE) - Project Phase 113switching a load will cause switching surges, while switching a heavy load it causes the transients

Output atSteady state conditionTransient fault conditionTesting: (Effect of load switching)12/26/2013M.E(PSE) - Project Phase 114

Testing: (Effect of load switching)12/26/2013M.E(PSE) - Project Phase 115

Steady state output of the systemTesting: (Effect of load switching)12/26/2013M.E(PSE) - Project Phase 116Transient fault condition

ConclusionThe simulation results have shown that electromagnetic current transformers (EMCT) can suffer heavily from transient saturation during switching of heavy load and unsymmetrical switching. Based on this work it is safe to declare that EMCT can be used for normal monitoring and measurement applications in utility. It is not good for the reliable protection and control application in high power application. 12/26/2013M.E(PSE) - Project Phase 117Thank you12/26/2013M.E(PSE) - Project Phase 118