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Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Power System Protection
S.A.Soman
Department of Electrical EngineeringIIT Bombay
Power System Protection
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
1 OverviewElectrical Energy SystemsTypes of Protection
2 RelaysIntroductionEvolution of Relays
3 Circuit BreakerWhat is a circuit breaker?
4 Summary
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
1 OverviewElectrical Energy SystemsTypes of Protection
2 RelaysIntroductionEvolution of Relays
3 Circuit BreakerWhat is a circuit breaker?
4 Summary
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Electrical Energy is
Generated at few kV and stepped up.
Transmitted through AC and HVDC lines.
Stepped down and distributed at load centers.
Its natural mode of synchronous operation knits the systemtogether.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Why do we need protection?Electrical apparatus operates at various voltage levels andmay be enclosed or placed in open. Under abnormaloperating conditions protection is necessary for
Safety of electrical equipments.
Safety of human personnel.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
1 OverviewElectrical Energy SystemsTypes of Protection
2 RelaysIntroductionEvolution of Relays
3 Circuit BreakerWhat is a circuit breaker?
4 Summary
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Types of ProtectionApparatus Protection
Transmission Line ProtectionTransformer ProtectionGenerator ProtectionMotor ProtectionBusbar Protection
System Protection
Out-of-Step ProtectionUnder-frequency RelaysIslanding SystemsRate of Change of Frequency Relays
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Types of ProtectionApparatus Protection
Transmission Line ProtectionTransformer ProtectionGenerator ProtectionMotor ProtectionBusbar Protection
System Protection
Out-of-Step ProtectionUnder-frequency RelaysIslanding SystemsRate of Change of Frequency Relays
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Types of ProtectionApparatus Protection
Transmission Line ProtectionTransformer ProtectionGenerator ProtectionMotor ProtectionBusbar Protection
System ProtectionOut-of-Step ProtectionUnder-frequency RelaysIslanding SystemsRate of Change of Frequency Relays
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
1 OverviewElectrical Energy SystemsTypes of Protection
2 RelaysIntroductionEvolution of Relays
3 Circuit BreakerWhat is a circuit breaker?
4 Summary
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
What is a Relay?A relay is a logical element which process the inputs (mostlyvoltages and currents) from the system and issues a tripdecision if a fault within its jurisdiction is detected. Inputs toa relay are
Current from a current transformer.Voltage from a voltage transformer.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
1 OverviewElectrical Energy SystemsTypes of Protection
2 RelaysIntroductionEvolution of Relays
3 Circuit BreakerWhat is a circuit breaker?
4 Summary
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Evolution of RelaysIf we zoom into a relay, we can see three different types ofrealization:
Electromechanical Relays.
Solid State Relays.
Numerical Relays.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Electromechanical Relays
First generation ofrelays.
Uses the principle ofelectromechanicalenergy conversion.
Immune toelectromagneticinterference and rugged.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Solid State RelaysThese relays were developed with the advent of transistors,operational amplifiers etc. Their functionality is throughvarious operations like comparators etc. Their advantagesare
More flexible.
Self checking facility.
Less power consumption and low burden.
Improved dynamic perfomance characteristics.
High seismic withstand capacity.
Reduced panel space.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Numerical RelaysOperation of a numerical relay involves analog to digitalconversion of voltage and currents obtained from VT andCTs. These samples are fed to the microprocessor or DSPwhere the protection algorithms process these signals andnecessary decisions are taken.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Its advantages are
Maximum flexibility.
Provides multiple functionality.
Self checking and communication facility.
It can be made adaptive.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
1 OverviewElectrical Energy SystemsTypes of Protection
2 RelaysIntroductionEvolution of Relays
3 Circuit BreakerWhat is a circuit breaker?
4 Summary
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
What is a Circuit Breaker?A circuit breaker is basically a switch to interrupt the flow ofcurrent.
It opens on relay command.
It has to handle large voltages and currents.
The inductive nature of power system results in arcingbetween the terminals of a CB.
CBs are categorized based on the interrupting mediumused.
Power SystemProtection
S.A.Soman
OverviewElectrical EnergySystems
Types of Protection
RelaysIntroduction
Evolution of Relays
CircuitBreakerWhat is a circuitbreaker?
Summary
Introduction
Summary
Necessity of a protection system.
Types of Protection.
Three generations of relays.
Role of circuit breakers.
