What are the fundamental requirements for a protection system in an AC transmission line?

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What are the requirements of transmission line protection?

The protection scheme must satisfy the following requirements: a) Under normal conditions the breakers are not tripped. b) Under fault conditions only the breakers closest to the fault on the source side are tripped. c) If the closest breaker fails to operate, the next breaker closer to the source should trip.

What are the basic requirements of a protection system?

• The fundamental requirements for a protection system are as follows:

  • Reliability:
  • Speed:
  • The Relay Time :
  • The Breaker Time:
  • Selectivity:
  • Sensitivity:
  • Stability:
  • Adequacy:

What are the fundamental requirements of protective relaying?

Fundamental Requirements of Protective Relay:

  • Selectivity.
  • Speed.
  • Sensitivity.
  • Reliability.
  • Simplicity.
  • Economy.

What are the primary requirement of a transmission line?

The primary function of a transmission line structure is to support the transmission lines. The design of the transmission line structure must consider environmental conditions, area requirements, voltage levels, and right-of-way (ROW) requirements.

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Why is the protection of transmission lines important?

As you already know, the real purpose of transmission line protection is to detect faults or abnormal operating conditions and to initiate corrective action. Protective relays must be able to evaluate a lot of parameters to choose and establish right corrective action. Obviously, a relay cannot prevent the fault.

Which protection used for protection of transmission line is unit type protection?

1. Transformer Unit Protection. transformers in the low and high voltage and neutral ends of the windings are connected in parallel to form a circulating current scheme.

What is the requirement of power system protection?

Performance and design criteria for system-protection devices include reliability, selectivity, speed, economy, and simplicity. Reliability: Devices must function consistently when fault conditions occur, regardless of possibly being idle for months or years. Without this reliability, systems may cause costly damages.

What are the components of protection system?

Components of protective system

A protection system consists of Current & Voltage Transformers, protective relays, circuit breakers, and batteries.

What are the requirements of protective relaying explain with the help of examples?

A protection relay mainly works as a sensor. It may find out the fault location and then signal the operation of the circuit breaker. The circuit breaker cuts off the faulty system from the rest of the system and the continuity of the electrical supply is not hampered.

What are the three basic components of a protective relay scheme?

There are three principal components of a protection system: Transducer. Protective relay. Circuit breaker.

What are the basic elements of transmission systems?

The transmission system consists of the following components:

  • Clutch.
  • Gearbox.
  • Propeller shaft.
  • Differential.
  • Live Axle.

What are the main components of power transmission system?

The main components of high-voltage electric transmission lines and associated facilities include:

  • Transmission Towers. Transmission towers are the most visible component of the power transmission system.
  • Conductors (Power lines)
  • Substations.
  • Rights of Way (ROWs)
  • Access Roads.

What are the types of protection scheme?

Consists of mainly power system protection relays like current relays, voltage relays, impedance relays, power relays, frequency relays, etc. based on operating parameter, definite time relays, inverse time relays, stepped relays etc.

What are the factors to consider in the selection of protective relays in transmission lines?

The high level factors influencing line protection include:

The system feeding the line, The configuration of the line (the number of terminals, the physical construction of the line, the presence of parallel lines), The line loading, The types of communications available, and.

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What are the main objectives of power system protection?

The objective of power system protection is to isolate a faulty section of electrical power system from rest of the live system so that the rest portion can function satisfactorily without any severer damage due to fault current.

What are protection systems?

Current Approved Definition: Protective relays, associated communication systems, voltage and current sensing devices, station batteries and DC control circuitry.

What are the two types of protection?

It is a usual practice to divide the Types of Protection scheme into two classes viz. primary protection and back-up protection.

How many types of protection relays are there?

Based on operation mechanism protection relay can be categorized as electromagnetic relay, static relay and mechanical relay. Actually, a relay is nothing but a combination of one or more open or closed contacts.

What are the three types of transmission lines?

Types of transmission line include parallel line (ladder line, twisted pair), coaxial cable, and planar transmission lines such as stripline and microstrip. The higher the frequency of electromagnetic waves moving through a given cable or medium, the shorter the wavelength of the waves.

What are the properties of transmission line?


  • Inductance- alternating current creates changing magnetic flux which in turn impedes change of current.
  • Resistance- this is opposition to the flow of current.
  • Capacitance- there exist capacitance between two conductors as long as they are separated by a dielectric medium.

What are the four main components of automatic transmission?


  • Clutch. The clutch pack inside of an automatic transmission is comprised of several discs inside of a drum.
  • Bands. Essentially bands of steel with frictional material, the bands of an automatic transmission will tighten under pressure.
  • Torque Converter.
  • Valve Body.

What are the four main components of automatic transmission construction?

There are four main parts of a torque converter in most modern vehicles: 1) the pump, 2) the stator, 3) the turbine, and 4) the torque converter clutch.

What are the 3 major components of electrical power system and explain their functions?

Electrical power supply system consists of three major parts: generation units, to produce electricity, transmission units to transport electricity from the generating plant to the area to be used and distribution units, to connect the individual customers to the electrical power system[1].

What is distance protection of transmission lines?

Distance Protection is a Non-unit System of Protection, which measures the Impedance between the Relay Location and the point where the fault is incident and compares it with the Set Value. If the measured Impedance is less than the Set Value , the Relay operates and Isolates the Faulty Section.

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Which relay is used for protection of short transmission line?

Reactance relay is suitable for the protection of a short transmission line because its operation is independent of arc resistance. Reactance relay is used for the phase faults in a short transmission line.

What are the 5 different types of relay?

What are the Types of Electrical Relays

  • Electromagnetic relay. Electromagnetic relay is the simplest, oldest and most widely used relay.
  • Latching relay.
  • Thermal relay.
  • Reed relay.
  • High voltage relay.
  • Time Relay.
  • Current and voltage relay.
  • Differential relay.

What are the four parts of power system?

The power delivery system includes four components: (1) the grid, or high-voltage transmission system that connects the bulk power generation system with the distribution systems; (2) the distribution system, which delivers power to consumers (or electrical “loads”); (3) the operations system, which handles …

What are the four types of power distribution system?

There are three basic types of distribution system designs: Radial, Loop, or Network. As you might expect, you can use combinations of these three systems, and this is frequently done. The Radial distribution system is the cheapest to build, and is widely used in sparsely populated areas.

Which is a line protection device?

Line Protection Devices, Surge Protector, Transient Voltage Surge Suppressor, SPD, TVSS, Voltage Surge Suppressor in Indraprastha Extension, Delhi , Promo Hospitality Private Limited | ID: 15912548248.

What are the different types of protection devices used in power system?

Some examples of electrical protection devices are lightning arresters, surge protectors, fuses, relays, circuit breakers, reclosers, and other devices. Every electrical circuit has a maximum voltage or amperage. If this value is exceeded, the wire will overheat, causing the wire insulation to melt and fire to ignite.

What are the requirements of power system protection?

The following are the basic requirements of any power system protection system:

  • Reliability.
  • Simplicity.
  • Selectivity.
  • Sensitivity.
  • Speed of operation.
  • Economy.

What are the different types of protection of transmission line?

If we consider about the protection of transmission line there are three protection types are used to protect these lines .

  • Differential Protection.
  • Phase Comparison.
  • Over Current Protection.
  • Earth fault overcurrent protection (Use for protect from large residual current)
  • Distance Protection.

Which of the following relay is provided as the primary protection of transmission lines Mcq?

Answer. 7. Which of the following relay is used for phase fault protection of short transmission lines ? (a) Reactance relay.

Which type of relays are required for full protection of 3 phase line?

For complete protection of a 3-phase transmission line, we require Two-phase and one-earth fault relays.