Wuhan UHV specializes in producingseries resonance (also known as series resonance test equipment). Next, we will share with you the selection of reactance rate for series resonance reactors.

As a common low-voltage reactive power compensation device, power capacitors are commonly used to improve the power factor of power systems, ensure the safety and stable operation of the power grid. Usually, a series reactor is also connected in the capacitor circuit, with two main purposes: limiting inrush current and suppressing harmonics. Because capacitors will amplify the harmonics injected into the system after being put into the power grid, exacerbating the harm of harmonics. How to choose the reactance rate of a series reactor based on the different purposes of capacitors?  

Selection of reactance rate

The reactance rate is an important parameter of a reactor, and its magnitude will directly affect its function and the safety of the system. In order to select the appropriate reactance rate, it is necessary to understand the background of harmonics in the power grid where capacitors are connected. Only after measuring each harmonic can capacitors be matched with reactors connected in series.  

(1) When the background harmonic at the connection point of the compensating capacitor is third order and the content exceeds or approaches the standard, a 12% series reactor should be selected.  

(2) The background harmonics at the connection point of the compensating capacitor are mainly 3rd and 5th order, and both have a large content. It is recommended to use a series reactor with a mixed reactance rate of 12% and 4.5%~6% to ensure the suppression of 3rd harmonic amplification. The advantage of this scheme is that it can reduce reactive power loss compared to using a 12% series connection scheme.

(3) When the background harmonic at the connection point of the compensating capacitor is mainly 3rd order and contains more than 5th order harmonics, but the content is relatively low, a 0.1-1% reactor can be selected.  

(4) When the background harmonics at the connection point of the compensating capacitor are mainly 3rd and 5th harmonics, but the 3rd harmonic content is relatively low, and the 5th harmonic content has exceeded or approached the standard value, a 6% series reactor should be selected.

(5) When the background harmonic at the connection point of the compensating capacitor is 5th or higher, and the 5th harmonic content is relatively high, a 6% series reactor should be selected.  

After configuring the reactor, it should be converted whether harmonic amplification can occur. If harmonic amplification occurs, the reactor parameters should be changed.