Overview

The circuit breaker failure protection provides a backup protection in the case, that the local circuit breaker fails to clear a system fault.In this training we have started from basic concepts, explained circuit breaker symbol and how circuit breaker look like in substation. We have discussed in training how to represent circuit breaker by ANSI code, difference of circuit breaker and line isolator. What are different functions that are performed by circuit breaker, what is arc, how to quench arc, what are media to quench arc, what will happen if arc is not quenched. Trainer Introduction:Your trainer brings over 21 years of experience in operation & maintenance, erection, testing, project management, consultancy, supervision, substation automation, SCADA, and commissioning. With a background spanning power plants, high voltage substations, and HVDC installations, he has worked with renowned organizations such as Siemens Saudi Arabia. He has been involved in over 20 high-voltage substation projects across Pakistan and Saudi Arabia.His expertise encompasses a wide range of areas including protection systems, substation automation systems, design, testing, and commissioning of power generation systems, high voltage switchgear, protection relays, and control schemes. He has a proven track record of leading testing and commissioning teams for implementing electrical infrastructure projects for industrial clients, including steel and petrochemical industries.We have discussed different components of circuit breaker that include CB closing coil, tripping coils, auxiliary contacts, normally open and normally close contacts, simplified protection system consisting of DC battery banks/charger, relays, Current and voltage transformers, why CT & VTs are required at substation, what do you understand by CT ratio 1000/1, use of redundant DC supplies, why DC is used not AC for control & trip functions, how circuit breaker spring is charge, circuit breaker operation, what is trip free/ready to trip function of CB, Trip Circuit Supervision feature, DC supply supervision, trip coil supervision, TCS Relay, control & protection DC supplies & Tripping coils, what is typical tripping and closing time of circuit breaker. What are different types of breaker failure that can occur in power system:Circuit Breaker Failure due to Mechanism FailCircuit Breaker Failure due to non-interruption of fault currentCircuit Breaker Failure due to DC control/trip supply fail Circuit Breaker Failure due to tripping coil failureCircuit Breaker Failure due to low DC voltageCircuit Breaker Failure due to Aux contact failureCircuit Breaker Failure due to FireCircuit Breaker Failure due to delayed trippingCircuit Breaker Pole Discrepancy What is Circuit Breaker Pole Discrepancy:Single pole & three pole circuit breaker operated mechanismsadvantages of single pole tripping & reclosingHow single pole reclosing support systemWhat is meaning of pole discrepancy How pole discrepancy is detected in system Pole discrepancy circuit working Timer circuit in pole discrepancyStage 1 & Stage 2 operations of pole discrepancyPole discrepancy during closing command & tripping command.Re-trip and 2nd stageWhat is typical time settings for Pole discrepancyCreation of 3I0 zero sequence current during pole discrepancy conditionHow Pole Discrepancy can lead to indiscriminate tripping in the networkBusbar Schemes:In order to understand it is good idea to learn about busbar schemes, we will go through following busbar schemes.Single Bus Single Breaker SchemeDouble Bus Single Breaker SchemeOne and half breaker schemeMesh Breaker schemesdouble bus and double breaker How to change over load from one bus to another bus without interruption Advantages of different busbar schemeCircuit Breaker Fail Philosophy:Circuit breaker failure protection using relay coordination at low / MV levels What to do & protect if one breaker failUnderstand basic concept of breaker failure, if some one understand well can design and understand all CBF protection schemes & logicCBF protection example in one and half breaker scheme, how to protect system if middle breaker fail , How to protect system if main breaker fail.CBF protection example in double bus double breaker busbar, consider the case of bus coupler & bus sectionalizer.Circuit Breaker Failure Logic, Function:Circuit Breaker Failure logic blockCBF initiation functionCBF current guardCBF Low current modeCBF CB Aux contact inputCBF timer CBF stage 1 & Stage 2 CBF for Mechanical Protection not involving currentCBF protection and End fault protection CBF Re-trip & 2nd stage faulty CB isolation from sourcesCBF when Circuit Breaker is faulty CBF and lockout function, 86 close block relayCBF & CB close blockingCBF typical times for stage 1 & stage 2 & when CB faulty By completing this course you will be able to understand circuit breaker failure relay function, Circuit breaker failure scheme/trip matrix, how CBF stage 1 & 2 operate, CBF protection for different busbar schemes. I wish you best of luck for the course.Best Regard Elite Engineering

Skills

Reviews