What is a Reactors?Different types of Reactors

Introduction

Reactors are essential components in electrical power systems, playing a key role in controlling reactive power flow, which is necessary for maintaining power grid voltage levels and stability. This blog will investigate reactors, their various types, and the vital functions they serve in ensuring the reliability of electrical networks.

Understanding Reactors

Reactive power does not do physical work, but it moves between the source and the load. Reactors help manage this power flow, improving power system efficiency and stability by adjusting the phase relationship between voltage and current.

Types of Reactors

Shunt and series reactors are very important components of the power system.The design of reactors, which have only one winding, is similar to that of transformers in many aspects. Their special features are highlighted below.

1.Shunt reactors

These are used to compensate for the capacitive volt-amperes generated during no-load or light-load conditions in high voltage transmission networks, thereby helping to maintain the voltage profile within desirable limits.Shunt reactors are installed at a number of places along the length of the transmission line. They can be either permanently connected or of a switched type.
Those that are permanently connected may result in poor voltage levels and increased losses under normal operating conditions. Hence, the switched types are better since these are connected only when the voltage levels need to be controlled. When connected to the tertiary winding of a transformer with a suitable rating, they become cost effective. The voltage drop due to a high impedance value between the HV winding and the tertiary winding must be taken into account while deciding the voltage rating of the reactors connected to the tertiary winding.
Shunt reactors can be of coreless (air-core) or gapped-core (magnetic circuit with non-magnetic gaps) design. The flux density in the air-core reactors has to be lower as the flux path is not well constrained. Eddy losses in the winding and stray losses in the structural conducting parts are higher in this type of design.
In contrast, the gapped-core design is compact due to a higher permissible flux density. The gaps between core packets can be suitably designed to achieve a desired reactance value.Shunt reactors are usually designed to have constant impedance characteristics up to 1.5 times the rated voltage to minimize harmonic currents in overvoltage conditions.

2.Series reactors

These reactors are connected in series with generators, feeders and transmission lines to limit fault currents under short-circuit conditions. These reactors should have linear magnetic characteristics under fault conditions. They should be designed to withstand the mechanical and thermal effects of short circuits.
The winding of series reactors used for transmission lines is of the fully insulated type since both the ends should be able to withstand lightning voltages.The value of the series reactors has to be judiciously chosen because higher value reduces the power transfer capability of the lines. Smoothing reactors used in HVDC transmission systems smoothen out the ripple in the DC voltage.

3.Variable Reactor

Adjustable dummy reactors are series-connected and parallel canceling inductors like power reactors, and they modify the reactance of the active hookup, so managers adjust the opposition to alternating current caused by capacitance or inductance in the system.
Variable reactors are usually made of windings of different dimensions (variable reactance) in order to change inductance and reactance. Usually, this can be achieved through taps built into these transformers which are used to change the number of turns of the windings. This in turn enables reactance adjustment. The closure of the manual or automatic taps governs these tap changers. Some variable reactors can have a flexible core shape to do the changing of the core shape mechanically and fine tune the reactance by this approach.
Voltage controllers of different type like automatic reactive controllert are typically used in power grid to shape voltage. They can install equipment that lower reactance, therefore stabilising the volatility of voltage. For the case of reactive power demand swings, the rotational reactors are capable of being switched on and off to serve or withdraw reactive power thus improveing PF and system stability. The responsiveness is benefitted by the option to vary reactance, and thus optimal flow of power and the power quality is being insured.
Moreover, harmonic filtering is another field where use of variable reacting rises to a need of controlling the harmonic flow in power systems and thus enhancement of the power quality is achieved. Besides that, in the HV transmission lines, the vary reactors are used for the line compensation with Dynamic Reactance by chaning the reactance value to achieve a perfect power flow and also to control line's parameters that change over time.

4.Tuned Reactors

Synchronized reactors, which could be referred to as detuned reactors or harmonic filters as well, perform such function vibrating at a particular frequency. Unlike usual reactor that provide inductive or capacitive reactance at broad frequency range, the tuned reactor focus on the immediate small range and proportional worsening of the harmonics at resonance frequency.
Resonant reflectors are tuned devices designed to have an inductance and a capacitance resonant circuit together tuned to a single harmonic frequency. Some power systems can be amended to accommodate storms with their specific frequency of the harmonic so it is easy for electricity flow as originally intended. These might as well comprise of filtering components that provide distortion and regulating harmonic currents and disperse them onto the network.
Advanced control systems, i.e. harmonic filters, are widely employed to act against harmonic distortion in power systems. They are cleverly located at strategic places to neutralize the frequency spectrum of harmonics and better power quality. In VFDs, the role played by tuned reactors becomes pivotal, as these mitigate the harmonic distortion that is often caused by speed variation, therefore promoting optimum motor operation, and insulating other devices from disruption.
Corrective reactors are indeed crucial in high power factor balancing, where the problem of harmonic currents often arises, by leading to a large inequality of the reactive power. Similarly, they aid in the improvement of the power quality through their complementary zero phase angle which generates harmonic voltage distortion and thus providing a stable voltage supply. Also, tunes of reactors on the other way round yields to resonance problems in power systems by supplying controlled path for harmonic currents.

5.Arc Suppression Reactors

Arc suppression reactors are the devices that are made to terminate the time and brightness of electric arcs which take place when a current goes through a distance between fast lane materials and leads to plasma exposure. These jets often could be fatal destroying equipment, machines, and imperiling crews. Electromagnetic drum wheel which when rotated around the arc blocks the energy particle before the arc can start to diminish the energy.
Arc suppression reactors usually have an iron core that allows for a low-resistance path for the magnetic flux produced when the arc is interrupted. The reactor contains windings that create a magnetic field when current passes through them, which is essential for suppressing and extinguishing the arc. A quenching method is used in arc suppression reactors to quickly reduce the energy in the arc, which may include introducing a reactive substance like air or gas to cool and put out the arc.
Arc suppression reactors are commonly used in circuit breakers to improve their ability to extinguish arcs. They are also used in medium and high-voltage switchgear to enhance arc interruption and prevent damage. By swiftly extinguishing arcs, these reactors enhance the safety of power distribution systems and protect against arc flash incidents in industries with high-power equipment.

6.Smoothing Reactors

Induction smoothing reactors are particularly designed for the purpose of off-seting the voltage fluctuations and to improve Power quality in power systems. Shifts in load may increase voltage, switching activities may suddenly alter voltage, and faults in the grid may make the line voltage to deviate from standard limits. Smooth reactor benefits the system in the way that it absorbs and smooths out these fluctuations, hence functions as a buffer implying that the level of stability and dependability for the whole system is increased.
Namely, the key of a smoothing reactor could be an iron or other magnetic material encouraging flux to follow an easier route for that flux. The scavenger contains windings, which current runs through, measuring its readiness for smoothing voltages. Apart from capacitive filtering components like capacitors and other devices that may be used to rupture and eliminate these harmonics could also be included.
Smoothing reactors have been widely applied in power systems for variations in voltage levels. Now, consumers do not experience abnormal fluctuations in power supply and expensive equipment is not destroyed due to inconstancy. Industries that have big power supply use these reactors to ensure stable power as their equipment needs stable operations and gadgets.
For instance, reactors known as smoothing reactors have a facilitator role where they mitigate the voltage variation spikes from unpredictable sources like wind turbines and solar power inverters, hence creating a firm grid where these resources can be integrated seamlessly. Through this, they help to give a better power factor, thus, reduce voltage sags, harmonics, and other disturbances that may affect applications with a critical nature such as data centers and key infrastructures.

Conclusion

Absolutely, generators of different functions are standing as cornerstone on the electrical power systems strength which are the correlation between efficiency and reliability of the electric power system. Consequently, being aware of their significance is very necessary for developing a solid architecture in a dynamic sector of power systems engineering.