In general, relay protection is not provided in the following cases alternator field failures.
Which of the following protection is not provided for alternator?
Therefore, overvoltage protection is not provided with turbo alternator sets. 6.
Which protection is provided for alternator?
Differential or Merz-Price Protection is most commonly used to protect alternators against stator winding faults because of its sensitivity and reliability.
Which method is best for field failure protection of alternator Mcq?
Low Frequency Relays: Low frequency relays are used to protect the alternator when the frequency falls below the operating frequency.
Which of the following are faults of alternator?
Critical faults that can occur with alternators include overvoltage, overspeed, overcurrent, prime mover failure, unbalanced loads, field and stator winding failures (including line-to-ground, line-to-line, and double-line-to-ground failures). , three-phase failures and interturn failures).
How many types of alternator protection are there?
Generator protection is broadly divided into three types: Class A, B, and C. Class A covers all electrical protection against faults within the generating unit that require tripping the generator field breakers, generator breakers, and turbines.
Why over current protection is not necessary for alternator?
Answer: Overload protection is not critical for alternators because overloads rarely occur in power plants. Explanation: The possibility of an alternator overload fault is negligible. The actual amount of power generated depends on the prime mover, which is continuously monitored and regulated by the governor and regulator.
Which one is used for protection of stator fault in generator?
1. generator grounding. The neutral point of the generator is usually grounded to facilitate protection of the stator windings and associated systems. Grounding also prevents damage from transient overvoltages in the event of an arc ground fault or iron resonance.
What is the purpose of alternator Mcq?
Solution (by the Examveda team) Alternators are used in modern automobiles to charge the battery and provide power to the electrical system when the engine is running.
Which relay is used for protection of alternator from loss of excitation?
There are two main methods of protection against field losses or generator excitation. The first scheme uses a short-current relay connected by a shunt to the main field winding circuit. This relay operates when the excitation current falls below a predetermined value.
What is function of Buchholz relay?
A typical Buchholz relay has two sets of contacts. One is arranged to slowly accumulate gas and the other to discharge a large amount of oil in the event of a severe internal fault. An alarm is generated for the former, while the latter is usually wired directly to the circuit breaker trip relay.
Why Merz Price protection is not suitable beyond 33kV?
Balancing the CT secondary is difficult, which is why Merz-Price protection is not employed above 33kV.
Which type of turbine is used for turbo alternator Mcq?
Clarification: Turbo alternators are one category of synchronous machines. They are driven by steam turbines.
How many types of rotors are used in alternator Mcq?
Alternator Rotor Type MCQ Question 2 Butt rotor type: Suitable for high speed operation with no speed fluctuation. Cylindrical rotor type: Suitable for low and medium speed operation with speed fluctuation.
Which one of the following is a type of alternator?
Automotive alternators – used in modern automobiles. Diesel-electric locomotive alternators – used in diesel-electric multiple units. Marine alternators – used in marine applications. Brushless alternators – used as the primary power source in power plants.
What is the working principle of alternator Mcq?
The principle of operation of alternators relies on Faraday’s law of electromagnetic induction. This law states that when there is relative motion between a conductor and a magnetic field, a current is induced in the conductor within the field.
What is loss of excitation protection?
Loss excitation protection is used to protect a synchronous machine (alternator or generator) that acts as an induction motor when excitation fails. Loss excitation protection can operate under a number of circumstances, including diode failure, short-circuit in the rotor winding, and AVR failure.
What is generator protection?
Generator protection. 17. power system protection is the branch of power engineering that deals with protecting the power system from failure by disconnecting the failed component from the rest of the power network.
What are the types of protection?
Types of Protection
- High-voltage power grid.
- Generator sets.
- Overload and distance backup (overcurrent).
- Ground faults/ earth faults.
- Distance (impedance relay)
- Backup.
- Low voltage networks.
- Cyber security.
Which of the following is protection for transformer unit?
Transformer Unit Protection All transformers have the same secondary current rating and can use simple instantaneous relays (protection is not affected by inrush currents or tap changes).
Short circuit, high voltage, high frequency disturbances including lightning, and pure ground faults.
What are the two types of protection given for busbar?
There are two types of busbar protection of this type: low-impedance bias differential protection and high-impedance differential protection, as described here.
What is transmission line protection?
As you know, the real purpose of transmission line protection is to detect a fault or abnormal operating condition and initiate corrective action. The protective relay must be able to evaluate a number of parameters in order to select and establish the appropriate corrective action.
What is motor protection?
Motor protection is used to prevent damage to electric motors, such as internal motor faults. It must also detect external conditions during connection to the power grid or during use to prevent abnormal conditions.
What is frame leakage protection?
Essentially, frame leakage is a ground fault type of protection. A current transformer installed in the frame to ground connection monitors the fault current and activates an instantaneous relay. The fault measurement connection is the only link to ground.
Which relay is used for transformer protection?
Protection of the transformer against overloads is usually performed by a dedicated protection called a thermal overload relay.
What type of relay is a Buchholz relay?
Buchholz relays are a type of gas detection relay. A Buchholz relay has two main elements. The upper element consists of a float. The float is mounted on a hinge and moves up and down depending on the oil level in the Buchholz relay container.
What is Merz Price protection of generator?
Bias differential scheme for generator protection (Merz-Price scheme): This is the most commonly used protection scheme for stator windings in alternators. This scheme is also called bias differential protection and percentage differential protection.
Which relay provide signal before the fault Mcq?
Thus, a Bucholz relay is a relay that provides a signal in the event of an initial fault and before a significant fault occurs.
What is a three-phase fault?
A three-phase bolted fault represents a condition in which three conductors are physically held together with zero impedance between them, as if they were bolted together. In a balanced symmetrical system, the magnitude of the fault current is evenly balanced within the three phases.
What is ground fault?
A ground fault is an inadvertent contact between an energized conductor and ground or grounded equipment frame. The return path of the fault current passes through the grounding system and the personnel or equipment that is part of that system. Ground faults are often the result of an insulation breakdown.
How many types of faults can occur in a system Mcq?
Single line to ground faults (LG faults) Line to line faults (LL faults) Two line to ground faults (LLG faults) Three phase faults.
Which type of relay is used for protection of transmission line?
Distance relays are a type of protective relay most often used to protect transmission lines. Distance relays measure the impedance from the installation to the fault location and operate according to changes in the ratio of measured current to voltage.
Which type of rotor is generally used for high speed alternator or turbo-alternator Mcq?
Smooth cylindrical rotors are typically used in high-speed alternators or turbo-alternators.
Which type of alternator is used in thermal power plant?
Plants are butt-pole alternators. Turbo generators essentially generate electricity with a turbine connected to a generator, and these turbo-generators can also be used as auxiliary power units. Non-protruding rotors are used in nuclear, gas, and thermal power plants.
Which type of rotor is preferred for alternators applied to hydraulic turbines?
In synchronous generators and alternators, the projectile rotor is generally driven by a water turbine, while the cylindrical rotor is driven by a steam turbine. Key Points.
| Plunge-pole rotor | Cylindrical rotor |
|---|---|
| Large diameter and short shaft length | Small diameter and long shaft length |
Which type of rotor is used in low and medium speed alternators?
Butt-pole rotors are used on low-speed equipment from 100 rpm to 1500 rpm. Additional information.
| Plunge-pole rotor | Cylindrical rotor |
|---|---|
| Used in low-speed alternators | Used in high speed turbo alternators |
What is the purpose of alternator Mcq?
Solution (by the Examveda team) Alternators are used in modern automobiles to charge the battery and provide power to the electrical system when the engine is running.
Which of the following is not an advantage of alternator?
9. which of the following is NOT an advantage of alternators? Explanation: The lighter weight of the alternator increases the efficiency of the alternator. Surface contamination is eliminated because the output current does not flow through the commutator and brushes.
What are the uses of alternator?
The alternator as an integral part of every combustion engine vehicle, its primary responsibility is to convert chemical energy into electrical energy so that the battery and other electrical components in the engine can charge and replenish other electrical components in the vehicle.”
What are the parts of alternator?
Alternator components and their functions:.
- Regulator. The voltage regulator controls the amount of power distributed from the alternator to the battery to control the charging process.
- Rectifier.
- Rotor.
- Slip ring.
- Slip ring end bearing.
- Stator.
- Drive end bearing.
- Pulley.
When the speed of an alternator increases Mcq?
Thus, the speed of an alternator is directly proportional to its frequency. Therefore, increasing the frequency of the alternator will also increase its speed.
When an alternator is connected to the infinite bus bar Mcq?
If the alternator is connected to an infinite busbar, changes in the excitation of the alternator will change the terminal voltage and power factor.
What is reverse power trip?
The reverse power trip is to protect the machine driving the generator and to protect the electrical system from having to drive the gene if it becomes overloaded due to loss of generator input.
What is used for the protection of large alternator?
Generators are subject to electrical stresses imposed on the insulation of the machine, mechanical forces acting on various parts of the machine, and rising temperatures. These are the main factors that require protection for the generator or alternator.