Contents
A flexible alternating current transmission system (FACTS) is a system composed of static equipment used for the alternating current (AC) transmission of electrical energy. It is meant to enhance controllability and increase power transfer capability of the network.
What are the problems with AC transmission system?
The stability issues that limit the transmission capability include: transient stability, dynamic stability, steady-state stability, frequency collapse. Voltage collapse, and sub-synchronous resonance.
How flexible AC transmission systems devices are helpful for improving the system stability?
FACTS is a short form of Flexible AC Transmission System. These devices are used in a power system network to increase the power transfer capability of transmission line and it will increase the voltage stability, transient stability, voltage regulation, reliability, thermal limits of the transmission network.
What are the types of AC transmission?
Transmission can be of two types :
- HVDC Transmission (High Voltage Direct Current transmission)
- HVAC Transmission (High Voltage Alternating Current Transmission)
What is SIL in transmission line?
Surge impedance loading (SIL) of a transmission line is the MW loading of a transmission line at which natural power balance occurs.
Why STATCOM is used?
Uses. Usually a STATCOM is installed to support electricity networks that have a poor power factor and often poor voltage regulation. There are however, other uses, the most common use is for voltage stability.
What are the advantages of AC transmission system?
Advantages of AC Transmission
The AC voltage can be increased with the help of a step-up transformer or can be decreased using the step-down transformer easily and efficiently. Therefore, the AC transmission permits to transmit the electric power at high voltages and to distribute it at lower voltages.
What is shunt compensation?
Shunt capacitive compensation. This method is used improve the power factor. Whenever an inductive load is connected to the transmission line, power factor lags because of lagging load current. To compensate it, a shunt capacitor is connected, which draws current leading to the source voltage.
What is difference between series and shunt compensation?
The shunt capacitor does it by changing the power factor of the load, whereas the series capacitor does it by directly offsetting the inductive reactance of the circuit to which it is applied.
How does a SVC work?
In transmission applications, the SVC is used to regulate the grid voltage. If the power system’s reactive load is capacitive (leading), the SVC will use thyristor controlled reactors to consume VARs from the system, lowering the system voltage.
Why do we need FACTS controller?
FACTS controllers are products of FACTS technology
a group of power electronics controllers expected to revolutionize the power transmission and distribution system in many ways. FACTS technology can boost power transfer capability by 20-30% by increasing the flexibility of the systems.
What is the value of transient stability limit?
Answer: Lower than steady state stability limit.
What is corona effect?
DEFINITION: The ionization of air surrounding the high voltage transmission lines causing the conductors to glow, producing a hissing noise, is called Corona Discharge or Corona Effect.
What are the four 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.
What are the transmission line parameters?
The transmission line has mainly four parameters, resistance, inductance, capacitance and shunt conductance. These parameters are uniformly distributed along the line. Hence, it is also called the distributed parameter of the transmission line. …
What is G in transmission line?
The parameter G’ represents the isolation between the two conductors of the transmission line. C’ represents the capacitance between the two conductors that make up the tx line
L’ represents the inductance for one meter of the tx line. These parameters can be derived for each transmission line.
What is surge load?
Surge impedance loading is also defined as the power load in which the total reactive power of the lines becomes zero. The reactive power generated by the shunt capacitance is consumed by the series inductance of the line. If Po is its natural load of the lines, (SIL)1∅ of the line per phase.
What is surge impedance?
Surge Impedance is the characteristic impedance of a lossless transmission line. It is also called Natural Impedance because this impedance has nothing to do with load impedance. Since line is assumed to be lossless, this means that series resistance and shunt conductance is negligible i.e. zero for power lines.
Which type of controller is STATCOM?
A long transmission line needs controllable series as well as shunt compensation for power flow control and voltage regulation. This can be achieved by suitable combination of passive elements and active FACTS controllers.
What is the difference between SVC and STATCOM?
The main difference between a STATCOM and an SVC is the way they operate: a STATCOM works as a controllable voltage source while an SVC works as a dynamically controllable reactance connected in parallel.
What is working principle of STATCOM?
The basic principle of operation of a STATCOM is the generation of a controllable AC voltage source behind a transformer leakage reactance by a voltage source converter connected to a DC capacitor.
Why power loss is less in AC?
Because AC has the capability to step up the voltage and step down the voltage easily using transformers. And it has alternative current so noise immunity is also more than the DC. AC has higher loses for the same voltage from radiated 60/50 Hz “radio” waves and short circuit capacitance.
Why is AC preferred over DC?
AC voltage is preferred over DC voltage because it is economical and less complicated. AC voltage is more efficient than DC since minimum energy loss happens during transmission.
Why is AC used over DC?
The major advantage that AC electricity has over DC electricity is that AC voltages can be readily transformed to higher or lower voltage levels, while it is difficult to do that with DC voltages. Since high voltages are more efficient for sending electricity great distances, AC electricity has an advantage over DC.
What is shunt resistance?
Shunt resistance (Rsh) is defined as the slope of the dark current versus applied voltage to the detector.
What is uncompensated transmission line?
uncompensated transmission lines is given by. Where, Es=Sending end voltage. Er=Receiving end voltage Xt=Transfer reactance of transmission line δ = Load Angle. Higher voltage gives higher power flow limit. Higher voltage for same power gives lesser current and lesser I²R losses in line.
What is voltage stability?
Voltage stability is defined as ability of power system to sustain fixed tolerable voltage at every single bus of the network under standard operating conditions as well as after being subjected to a disruption (Kundur, 1994).
What is the power factor formula?
The power factor is the cosine of the phase difference between voltage and current, and as a result, the power factor is measured using the formula Power Factor = cosɸ, where ɸ is the phase difference between the voltage and current phasor.
Why shunt capacitor is installed at transmission distribution network?
Shunt capacitors help ease the lag between the current and voltage that occurs after an inductive load to the transmission line. For this reason, this option is reliable when it comes to stabilizing the system, improving the power factor, and increasing the line voltage.
What is power factor correction?
Power factor correction is the process of compensating for the lagging current by creating a leading current by connecting capacitors to the supply. A sufficient capacitance is connected so that the power factor is adjusted to be as close to unity as possible. Power factor explained.