News Category

Electrician Knowledge

The classification and role of three-phase reactor

What are the three-phase reactor classification? According to the structure and cooling medium, press the connection, according to the function, according to the use of classification.
1 by the structure and cooling medium: divided into hollow, core, dry, oil-immersed, such as dry hollow reactor, dry core reactor, oil core reactor, oil immersed hollow reactor, clamping Dry hollow reactor, wrapped around the dry hollow reactor, such as cement reactor.
2 press connection: divided into shunt reactor and series reactor.
3 function: divided into current limiting and compensation.
4 according to purpose: broken down by specific purposes, such as current limit reactor, filter reactor, smoothing reactor, power factor compensation reactor, series reactor, balance reactor, grounding reactor, arc suppression coil, Reactors, Saturated Reactors, Self Saturating Reactors, Variable Reactors (Adjustable Reactors, Controllable Reactors), Choke Reactors, Series Resonance Reactors, Shunt Reactance Reactors, etc.
Reactor as reactive power compensation means, in the power system is indispensable.
Shunt Reactor: Reactor for Full Load Test of Generator is the prototype of Shunt Reactor. Core-type reactor because of the existence of alternating magnetic cake between the core attraction, so the noise is generally higher than the same capacity transformer about 10dB.
Current-limiting reactor: Current-limiting reactor is generally used for distribution lines. Current-limiting reactors are usually used on branch feeders that exit from the same bus bar to limit the short-circuit current of the feeders and to maintain the bus voltage so that they will not be too low due to feeder short circuits.
Damping reactors (also commonly referred to as series reactors) are connected in series with capacitor banks or crowded capacitors to limit the capacitor inrush current. This point, the role of current-limiting reactors and similar filter reactor filter reactor and filter capacitor in series to form a resonant filter, generally used for 3 to 17 times the resonant filter or higher pass filter. HVDC converter stations, phase-controlled static compensation devices, large and medium-sized rectifiers, electrified railways, so that all high-power thyristor-controlled power electronic circuits are harmonic current sources that must be filtered out to prevent them from entering system. The power sector has specific provisions for harmonics in the power system. p
Arc suppression coil: Arc suppression coil is widely used in lOkV-6kV resonant grounding system. Because of substation oil-free tendency, so many arc suppression coils below 35kV are dry pouring type. p
Smoothing Reactor: Smoothing Reactor is used in the DC circuit after rectification. Rectifier circuit pulse number is always limited, the output of the straight voltage is always ripple. Such ripples are often detrimental and need to be rejected by smoothing reactors. DC converter converter stations are equipped with smoothing reactor, the output of DC close to the ideal DC. DC-powered thyristor electric drive, the smoothing reactor is also essential.
DC-controlled saturable reactor: string in the circuit choke or saturate reactor, in the voltage sine wave cycle, the saturable reactor saturates before absorbing a certain volt-second, reaching saturation, then was Fully open state. Therefore, the output voltage is non-sinusoidal, the role of this saturable reactor and thyristor similar.
The main components of the electrical circuit resistance, capacitance and inductance. Inductance has the role of curbing the current changes, and make the AC phase shift. Inductive effect of winding-type stationary sensing device called the reactor.
Reactor role
Reactors used in power systems are usually series reactors and shunt reactors. Series reactor is mainly used to limit the short-circuit current, but also in the filter with capacitors in series or in parallel to limit the higher harmonics in the power grid. Reactors in 220kV, 110kV, 35kV, 10kV grids are used to absorb the capacitive charge of the cable lines. The operating voltage can be adjusted by adjusting the number of shunt reactors. EHV shunt reactors have several functions that improve the reactive power of the power system in relation to operating conditions, including:
(1) Three-phase reactor light-load or light-load capacitive effect on the line to reduce power frequency transient over-voltage.
(2) Improve the voltage distribution on long transmission line.
(3) Make the reactive power in the line at light load as balanced as possible to prevent the unreasonable flow of reactive power and reduce the power loss on the line.
(4) Reduce the steady-state voltage on the HV busbar when the large unit and the system are in parallel, which makes it convenient for generators to be in parallel over the same period.
(5) to prevent the generator with long lines may appear self-excitation resonance phenomenon.
(6) When using the reactor neutral point through the small reactance grounding device, you can also use a small reactor to compensate the line phase and phase capacitance to speed up the sub-supply current automatically extinguished, easy to use.