What is a Reactors?Different types of Reactors

Introduction

Reactors are vital in electrical power systems, helping control reactive power flow essential for grid voltage and stability. This blog explores reactors, their types, and the crucial roles they play in maintaining the reliability of electrical networks.

Illustration of six different electrical reactors with various designs, labeled "What is a Reactors?" on a crumpled paper background, evoking a technical and educational tone.

Understanding Reactors

Reactive power doesn’t perform physical work but moves between source and load. Reactors manage this flow, enhancing system efficiency and stability by adjusting the voltage-current phase relationship.

Types of Reactors

Shunt and series reactors are crucial in power systems. Designed with a single winding, they resemble transformers in many ways. Their unique features are outlined below.

1.Shunt reactor

These devices counter capacitive reactive power generated during light-load periods in high-voltage transmission systems, helping maintain voltage within operational limits. Shunt reactors are placed at various points along transmission lines and can operate either continuously or in switchable configurations.
Repeatedly engaged devices can cause poor voltage profiles and higher energy losses during normal operation. Switched variants are advantageous, activating only when voltage regulation is needed. Pairing them with a correctly sized transformer's tertiary winding improves cost-effectiveness. Selecting the right voltage rating requires analyzing the voltage drop due to high impedance between high-voltage and tertiary windings.
Shunt reactors follow two main designs: air-core (no core) or gapped-core (with intentional core gaps). These designs create flux paths with magnetic discontinuities due to materials with low magnetic conductivity. Air-core reactors, lacking magnetic flux constraints, suit only low flux density areas. Consequently, this design often incurs higher eddy current losses in windings and increased stray losses in nearby conductive components.
In contrast, gapped-core designs are more compact due to their ability to handle higher magnetic flux density. Engineers can fine-tune reactance by adjusting the air gap. Shunt reactors are typically built to maintain stable impedance even under voltages up to 1.5 times their rating, which is crucial for mitigating harmonic currents during overvoltage events.

2.Series reactors

These reactors limit fault currents by connecting in series with generators, feeders, and transmission lines. Engineers design them to reduce short-circuit effects. It's essential that they maintain linear magnetic behavior during faults and withstand the physical stress and heat rise that consistently occur during such events.
Power engineers commonly use carefully insulated series reactor coils in transmission systems due to their essential role. These components include terminations designed to withstand severe voltage surges, such as lightning. Precise rating calculations are critical before integration—overrated reactors can limit transmission capacity. Additionally, smoothing reactors play a key role in HVDC systems by reducing ripple in the direct current voltage.

3.Variable Reactor

Engineers design dummy reactors similarly to power reactors, using series and parallel inductor connections to neutralize their effects. They adjust system reactance, helping operators manage impedance from capacitive or inductive network elements.
Variable reactors use windings with adjustable configurations to change inductance and reactance. Engineers often implement taps in the design to vary the number of winding turns for precise control. Manual or automatic mechanisms operate the tap changers. Some reactors also feature a flexible core shape, enabling mechanical core adjustments to fine-tune reactance.
Engineers manage voltage regulation using various devices, notably automatic reactive controllers. These systems often reduce reactance to limit voltage fluctuations. Switched reactors adjust to reactive power needs by injecting or absorbing power, improving power factor and grid stability. Rapid reactance adjustment ensures quick response, efficient power transfer, and the maintenance of high power quality standards.
Engineers apply variable reactance in harmonic filtering to manage harmonic current within power systems and improve power quality. They also use variable reactors in high-voltage (HV) transmission lines for line compensation by employing dynamic reactance. This dynamic approach adjusts the reactance value to optimize power flow and regulate the time-dependent parameters of the transmission line.

4.Tuned Reactors

These reactors, also known as detuned reactors or sometimes harmonic filters, operate by resonating at a specific 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 finely tuned devices combining inductance and capacitance into a circuit resonating at a specific harmonic frequency. Engineers adapt power grids to manage disturbances at that harmonic, ensuring smooth power flow. These systems also use filters to control distortion and redirect unwanted harmonic currents across the grid.
Engineers commonly use advanced control systems like harmonic filters to combat distortion in power systems. Strategically placed filters neutralize harmonic frequencies and enhance power quality. In VFDs, tuned reactors reduce distortion from speed changes, ensuring optimal motor performance and shielding other devices from interference.
Corrective reactors are vital in high power factor balancing, where harmonic currents can cause significant reactive power imbalance. They also enhance power quality through their zero phase angle, which generates harmonic voltage distortion and stabilizes voltage supply. However, certain reactor tuning can lead to resonance issues in power systems by creating a controlled path for harmonic currents.

5.Arc Suppression Reactors

Arc suppression reactors terminate the duration and brightness of electric arcs that occur when current jumps across a gap between conductive materials, leading to plasma exposure. These arcs can become fatal, destroy equipment and machines, and endanger crews. An electromagnetic drum wheel rotates around the arc and blocks the energy particles before the arc can form, thereby reducing the energy involved.
Arc suppression reactors usually include an iron core that provides a low-resistance path for the magnetic flux generated when the arc breaks. The reactor uses windings that generate a magnetic field as current passes through them, playing a crucial role in suppressing and extinguishing the arc. Engineers apply a quenching method in these reactors to rapidly reduce the arc’s energy, often by introducing a reactive substance such as air or gas to cool and extinguish the arc.
Engineers commonly use arc suppression reactors in circuit breakers to improve arc extinguishing performance. They also install these reactors in medium and high-voltage switchgear to enhance arc interruption and prevent damage. By swiftly extinguishing arcs, the reactors increase the safety of power distribution systems and protect industrial environments with high-power equipment from arc flash incidents.

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.
Power systems commonly use smoothing reactors to control voltage variations, preventing abnormal fluctuations and protecting costly equipment from instability. Industries with high power demands depend on these reactors to ensure stable, reliable power for the consistent operation of their equipment and devices.
Engineers use smoothing reactors to reduce voltage spikes from unpredictable sources like wind turbines and solar inverters. These reactors stabilize the grid for better renewable integration, improving power factor and minimizing voltage sags, harmonics, and disturbances that could impact critical systems like data centers and essential infrastructure.

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.