Rikitar (Indukta): Tushen da Nau'ukan
Rikitar, wanda ake kira indukta, ya fara zama a cikin al'umma a lokacin da adan ya gudana a kan hanyar. Saboda haka, akwai inductance a cikin duk hanyar da ake gudana abubuwa. Amma, inductance na hanyar mai zurfi ita ce mai yawa da take fara zama a cikin al'umma. Rikitar masu amfani a halitta suka fito a cikin solenoid, wanda ake kira rikitar air-core. Don samun inductance, ana saka core mai ferromagnetic a cikin solenoid, wanda ya fara zama iron-core reactor.
1. Shunt Reactor
Shunt reactors na farkon shi suna amfani a cikin bayanin generator. Iron-core shunt reactors suna fara zama magnetic forces mai tsawonta a cikin core sections, wanda ya fara zama noise levels da suka fi 10 dB mafi yawan transformers da dukkan sama. Shunt reactors suna gudana alternating current (AC) kuma suna amfani don inganta system capacitive reactance. Suna haɗa a cikin thyristors don inganta regulation of reactive current da tsohuwar.
2. Series Reactor
Series reactors suna gudana AC current kuma suna haɗa a cikin power capacitors don ƙirƙira series resonance circuit don harmonics mai tsawonta (misali, 5th, 7th, 11th, 13th harmonics). Series reactors masu tsawonta suna da impedance values da suka ɗauke 5–6% kuma suna cewa su ne high-inductance types.
3. Tuning Reactor
Tuning reactors suna gudana AC kuma suna haɗa a cikin capacitors don ƙirƙira series resonance a harmonic frequency (n) da aka bayyana, don haka za ta ƙoƙarin harmonic component. Tuning orders masu amfani suna da n = 5, 7, 11, 13, da 19.
4. Output Reactor
Output reactor ya kunshi capacitive charging current a motor cables kuma ya kusa rate of voltage rise across motor windings zuwa 540 V/μs. Yana buƙata idan cable length bayan variable frequency drive (VFD) (4–90 kW) da motor ya ƙara 50 meters. Yana yi smooth VFD output voltage (reducing switching edge steepness), minimizing disturbances and stress on inverter components such as IGBTs.
Application Notes for Output Reactors:
To extend the distance between VFD and motor, use thicker cables with enhanced insulation, preferably non-shielded types.
Features of Output Reactors:
Suitable for reactive power compensation and harmonic mitigation;
Compensates for distributed capacitance in long cables and suppresses output harmonic currents;
Effectively protects VFDs, improves power factor, blocks grid-side interference, and reduces harmonic pollution from rectifier units to the grid.
5. Input Reactor
Input reactor ya kunshi voltage drops a cikin grid side during converter commutation, suppresses harmonics, and decouples parallel converter groups. Yana kunshi current surges caused by grid voltage transients or switching operations. Idan grid short-circuit capacity to VFD capacity ratio ya ƙara 33:1, relative voltage drop of the input reactor ya kasance 2% for single-quadrant operation and 4% for four-quadrant operation. The reactor may operate when the grid short-circuit voltage exceeds 6%. For a 12-pulse rectifier unit, a line-side input reactor with at least 2% voltage drop is required. Input reactors are widely used in industrial and factory automation control systems. Installed between the power grid and VFDs or speed regulators, they suppress surge voltages and currents generated by these devices, significantly attenuating higher-order and distorted harmonics in the system.
Features of Input Reactors:
Suitable for reactive power compensation and harmonic filtering;
Limits current surges caused by grid voltage transients and switching overvoltages; filters harmonics to reduce voltage waveform distortion;
Smoothes voltage spikes and rectifier commutation notches in bridge circuits.
6. Current-Limiting Reactor
Current-limiting reactors suna amfani a cikin distribution circuits. Su na haɗa a cikin feeder lines branching from the same busbar to limit short-circuit current and maintain bus voltage stability during faults, preventing excessive voltage drops.
7. Arc Suppression Coil (Petersen Coil)
Arc suppression coils suna amfani a cikin resonant grounded systems da 10kV–63kV. Suna ƙara da dry-type cast resin design saboda trend towards oil-free substations, especially for systems below 35kV.
8. Damping Reactor (often synonymous with Series Reactor)
Damping reactors suna haɗa a cikin capacitor banks or compact capacitors, limiting inrush current during capacitor switching—similar in function to current-limiting reactors. Filter Reactor: When connected in series with filter capacitors, they form resonant filter circuits, typically used for 3rd to 17th harmonic filtering or higher-order high-pass filtering. HVDC converter stations, phase-controlled static VAR compensators, large rectifiers, electrified railways, and high-power thyristor-based electronic circuits are all harmonic current sources that must be filtered to prevent harmonic injection into the grid. Power utilities have specific regulations regarding harmonic levels in power systems.
9. Smoothing Reactor (DC Link Reactor)
Smoothing reactors suna amfani a cikin DC circuits after rectification. Saboda rectifier circuits produce a finite number of pulses, the output DC voltage contains ripple, which is often harmful and must be suppressed by a smoothing reactor. HVDC converter stations are equipped with smoothing reactors to make the output DC as close to ideal as possible. Smoothing reactors are also essential in thyristor-controlled DC drives. In rectifier circuits, especially medium-frequency power supplies, their main functions include:
Limiting short-circuit current (during inverter thyristor commutation, simultaneous conduction is equivalent to a direct short-circuit at the rectifier bridge output); without a reactor, this would cause a direct short;
Suppressing the influence of medium-frequency components on the utility power grid;
Filtering effect—rectified current contains AC components; high-frequency AC is impeded by the large inductance—ensuring continuous output current waveform. Discontinuous current (with zero-current intervals) would cause the inverter bridge to stop, resulting in an open-circuit condition at the rectifier bridge;
In parallel inverter circuits, reactive power is exchanged at the input; therefore, energy storage elements—reactors—are essential in the input circuit.
Important Notes
Reactors in power grids are used to absorb capacitive reactive power generated by cable lines. By adjusting the number of shunt reactors, system operating voltage can be regulated. Ultra-high voltage (UHV) shunt reactors serve multiple functions related to reactive power management in power systems, including:
Mitigating the capacitive effect on lightly loaded or no-load transmission lines, reducing power-frequency transient overvoltages;
Improving voltage distribution along long transmission lines;
Balancing reactive power locally under light load conditions, preventing unreasonable reactive power flow and reducing line power losses;
Reducing steady-state power-frequency voltage on high-voltage busbars when large generators are synchronized to the grid, facilitating generator synchronization;
Preventing self-excitation resonance that may occur when generators are connected to long transmission lines;
When the reactor neutral is grounded via a small reactor, the small reactor can compensate for inter-phase and phase-to-ground capacitance, accelerating the self-extinction of residual currents and enabling single-pole auto-reclosing.
Reactors are connected either in series or in parallel. Series reactors are typically used for current limiting, while shunt reactors are commonly used for reactive power compensation.
Shunt Reactor: In ultra-high voltage long-distance transmission systems, they are connected to the tertiary winding of transformers to compensate for the capacitive charging current of transmission lines, limit voltage rise and switching overvoltages, and ensure reliable system operation.
Series Reactor: Installed in capacitor circuits, they are used when the capacitor bank is energized.
