Table of Contents
A synchronous condenser (also called a synchronous capacitor or synchronous compensator) is a DC-excited synchronous machine (large rotating generators) whose shaft is not attached to any driving equipment.
Why is it called a synchronous condenser?
Under excitation causes it to operate at a lagging power factor. When the motor is operated at no load with over-excitation, it takes a current that leads the voltage by nearly 90 degrees. Thus, it behaves like a capacitor and under such operating conditions, the synchronous motor is called a synchronous capacitor.
What is synchronous condenser Mcq?
A synchronous motor operates as a synchronous condenser when it is. operated at unity power factor. under-excited. over-excited. connected in parallel with condensers.
What is synchronous condenser discuss its applications?
A synchronous condenser is a synchronous motor running at no load and in over-excited mode. A synchronous motor in over-excited mode behaves as a capacitor which is indicated by a leading current or supply of VARs in the circuit by a synchronous motor.
What are the advantages of synchronous condenser?
Advantages of synchronous condenser: The reactive power can be adjusted continuously. They are giving better performance than the static capacitor in the high voltage system. Maintenance-free. A high degree of safety can be maintained. Higher life as compared with a capacitor bank.
How does a synchronous condenser work?
The synchronous condenser aids voltage regulation by drawing leading current when the line voltage sags, which increases generator excitation thereby restoring line voltage. A capacitor bank does not have this ability.
Where are synchronous condenser installed?
Installed at strategic intervals along a transmission system, synchronous condenser systems are either new electrical rotating equipment or existing turbogenerators reconfigured to perform as reliable grid stabilizers.
Which one of the following is known as synchronous condenser?
In electrical engineering, a synchronous condenser (sometimes called a synchronous capacitor or synchronous compensator) is a DC-excited synchronous motor, whose shaft is not connected to anything but spins freely.
What is the application of synchronous compensator Mcq?
What is the application of synchronous compensators? Explanation: The main application of the synchronous compensators is to control the reactive powers. They are used in the power supply networks.
Which of the following is true for synchronous condenser?
It is a synchronous motor with capacitor connected across stator terminals to improve power factor. It is an over-excited synchronous motor partially supplying mechanical load, and also improving power factor of the system to which it is connected.
Why Statcom is used?
The Static Synchronous Compensator (STATCOM) is used in an HVDC system to provide reactive power compensation. It makes use of the Voltage Source Converter (VSC) to synthesize a controllable sinusoidal voltage at the fundamental frequency.
How much does a synchronous condenser cost?
Normally, the mean cost for a synchronous condenser is between $10 to $40 per kVAR and the maintenance cost ranges from about $0.4 to $0.8/kVAR per year.
What do you mean by synchronous speed?
: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.
What are advantages and disadvantages of synchronous condenser?
(i) By varying the field excitation, the magnitude of current drawn by the motor can be changed by any amount. This helps in achieving step less control of power factor. (ii) The motor windings have high thermal stability to short circuit currents. (iii) The faults can be removed easily.
What power factor means?
Power factor (PF) is the ratio of working power, measured in kilowatts (kW), to apparent power, measured in kilovolt amperes (kVA). PF expresses the ratio of true power used in a circuit to the apparent power delivered to the circuit. A 96% power factor demonstrates more efficiency than a 75% power factor.
How the synchronous motor is used as asynchronous condenser?
Like capacitor bank, we can use an overexcited synchronous motor to improve the poor power factor of a power system. When a synchronous motor runs with over-excitation, it draws leading current from the source. We use this property of a synchronous motor for the purpose.
Is a synchronous condenser a generator?
Synchronous condensers are considered as motors without any connected load or generators without prime movers. They produce or absorb reactive power.
How do synchronous machines work?
A synchronous motor is one in which the rotor normally rotates at the same speed as the revolving field in the machine. The stator is similar to that of an induction machine consisting of a cylindrical iron frame with windings, usually three-phase, located in slots around the inner periphery.
Why synchronous motors are not self starting?
Above a certain size, synchronous motors are not self-starting motors. This property is due to the inertia of the rotor; it cannot instantly follow the rotation of the magnetic field of the stator. Once the rotor nears the synchronous speed, the field winding is excited, and the motor pulls into synchronization.
What is the ideal power factor?
The ideal power factor is unity, or one. Anything less than one means that extra power is required to achieve the actual task at hand. All current flow causes losses both in the supply and distribution system. A load with a power factor of 1.0 results in the most efficient loading of the supply.
What could be the reasons if a 3 phase synchronous motor fails to start?
what could be the reasons if a synchronous motor fails to start? Voltage may be too low. Some faulty connection in auxiliary apparatus. Too much starting load. Open-circuit in one phase or short-circuit. Field excitation may be excessive.
What is the application of synchronous motor?
Synchronous motors are normally used in applications in which a constant and precise speed is required. Typical applications of these low power motors are positioning machines. They are also used in robot actuators. Synchronous motors are also used in ball mills, watches, record players, and turntables.
How can we improve the power factor?
The simplest way to improve power factor is to add PF correction capacitors to the electrical system. PF correction capacitors act as reactive current generators. They help offset the non-working power used by inductive loads, thereby improving the power factor.
What is static capacitor?
Static Capacitor These static capacitors provides leading current which neutralize (totally or approximately) the lagging inductive component of load current (i.e. leading component neutralize or eliminate the lagging component of load current) thus power factor of the load circuit is improved.
What are different methods of starting of synchronous motor?
The motor is first started as a slip ring induction motor. The resistance is gradually cut-off as the motor gains speed. When it achieves near synchronous speed, DC excitation is given to the rotor, and it is pulled into synchronism. Then it starts rotating as a synchronous motor.
