Harmonic eliminator (primary harmonic eliminator, harmonic elimination resistor)
This product is a patented product of Nanjing Chuangdi Electric Co., Ltd., China patent number (ZL lxq2 harmonic eliminator
200420080 176.4), the patented product adopts hollow cylindrical structure, which naturally forms a convection duct, which is beneficial to heat dissipation and greatly increases the flow. The material is copper, which will not deform and has stable quality.
Edit the purpose of the detuned equipment in this paragraph.
The electromagnetic voltage transformer (hereinafter referred to as PT) in the 6 ~ 35kV neutral ungrounded power grid will be oversaturated when the bus is empty or appears less, and it may lead to ferromagnetic resonance overvoltage due to the excitation of closing charging or grounding fault elimination during operation. Abnormal phenomena such as unstable relative ground voltage, misoperation of grounding indication, melting of PT high-voltage fuse, etc. In severe cases, it will lead to PT burning, which will lead to other accidents. In this case, it is necessary to install a harmonic eliminator. [1] The principle of harmonic eliminator is essentially a large-capacity nonlinear resistor, which plays the role of damping and current limiting. It can play a good role in limiting the ferromagnetic resonance of voltage transformer. If the neutral point of 6 ~ 35kV power grid is not grounded, the primary winding of TV connected with Y0 on the bus becomes the only metal channel between the power grid and the ground. There is a transition process of charging and discharging the capacitor to the ground through the TV primary winding. Experiments show that at this time, there is often a power frequency half-wave inrush current with the maximum amplitude of several amperes passing through TV, which may blow the TV high-voltage fuse. After installing the harmonic eliminator, this inrush current will be effectively suppressed, and the high-voltage fuse will no longer be blown because of this inrush current.
Edit the current situation of harmonic eliminator in this paragraph.
At present, the harmonic eliminators on the market are mainly LXQ series (some manufacturers are RXQ). LXQ is a new harmonic canceller. L stands for nudity and XQ stands for detuning. The exposed harmonic eliminator is small in size and especially suitable for installation in switchgear. [2] The main material of the harmonic eliminator is SiC, which is connected by metal connectors. The early harmonic eliminators were connected with aluminum. Aluminum has been basically replaced by copper because of its low melting point and easy softening and deformation. Wiring diagram of LXQ harmonic eliminator
The main parameters of the harmonic eliminator are: voltage and resistance passing through 0.5mAp, voltage and resistance passing through 5mAp, current capacity, power, limiting voltage at both ends, etc. Among them, the most important is the current capacity, and the design must consider the neutral insulation with PT and the selection of the capacity of PT high-voltage fuse. [